Journal articles
Sanders D, Frago E, Kehoe R, Patterson C, Gaston K (In Press). A meta-analysis of biological impacts of artificial light at night. Nature Ecology and Evolution
Robinson BS, Inger R, Gaston KJ (In Press). A rose by any other name: plant identification knowledge & socio-demographics. PLoS One
Bennie J, Davies TW, Cruse D, Inger R, Gaston K (In Press). Artificial Light at Night Causes Top-down and Bottom-up Trophic Effects on Invertebrate Populations. Journal of Applied Ecology
Troscianko J, Briolat ES, Gaston KJ, Bennie J, Rosenfeld EJ (In Press). Artificial nighttime lighting impacts visual ecology links between flowers, pollinators and predators. Nature Communications
Gardner AS, Maclean IMD, Gaston KJ (In Press). Climatic predictors of species distributions neglect biophysiologically meaningful variables. Diversity and Distributions
Sanchez De Miguel A, Kyba CCM, Aube M, Zamorano J, Cardiel N, Tapia C, Bennie J, Gaston KJ (In Press). Colour remote sensing of the impact of arti cial light at night (I): the potential of the International Space Station and other DSLR-based platforms. Remote Sensing of Environment
Phillips B, Bullock J, Osborne J, Gaston K (In Press). Ecosystem service provision by road verges. Journal of Applied Ecology
Zhang W, Sheldon BC, Grenyer R, Gaston K (In Press). Habitat change and biased sampling influence estimation of diversity trends. Current Biology
Sanders D, Kehoe R, Cruse D, Van Veen F, Gaston KJ (In Press). Low levels of artificial light at night strengthen top-down control in insect food web. Current Biology
Phillips B (In Press). Monitoring public engagement with nature using Google Trends.
People and NatureAbstract:
Monitoring public engagement with nature using Google Trends
1. How humans interact with nature affects the health of both people and ecosystems. Yet, long-term data on nature engagement are scarce because traditional survey methods are expensive, time consuming and require commitment over multiple years. Digital data sources (e.g. aggregated data from online searches) have major potential as a supplementary source of information and, in the absence of available data, as a proxy for more direct measurement of nature engagement.
2. Using Google Trends, we created a list of refined and relevant search terms relating to diverse outdoor spaces and activities. We then compared trends in Google search volumes in England across both a 1-year and 10-year period to those from Google Community Mobility Reports, and from nationally representative survey data (Natural England’s People and Nature Survey and the Monitor of Engagement with the Natural Environment).
3. Search, survey and mobility data all support a general increase in public engagement with nature since 2009, and a more substantial increase during, or following, the initial national ‘lockdown’ period of the COVID-19 pandemic in England. Search volumes increased for many urban and rural outdoor green spaces (e.g. woodlands), blue spaces (e.g. reservoirs), exercise activities (e.g. walking, running, and hiking), and explicitly nature-based activities (e.g. fishing, wild swimming, and encouraging wildlife).
4. Overall, volumes of Google searches were more closely related with longer-term (10-year) trends from survey data, than more subtle, shorter-term changes during the COVID-19 pandemic. There was a statistically significant relationship between search volumes, survey data (self-reported past behaviour) and mobility data (movement trends) for around half of comparisons. of these, an average of 13-44% of variation in the data was explained.
5. The findings show that Google Trends provides valuable information about public engagement with nature, which can help to supplement existing survey data by providing new insights about behavioural trends. The paper also provides a proof of concept for using Google Trends to understand changes in public engagement with nature, which could be applied to the many countries that lack long-term survey monitoring.
Abstract.
Cox D, Sanchez De Miguel A, Dzurjak S, Bennie J, Gaston K (In Press). National scale spatial variation in artificial light at night. Remote Sensing
Gaston KJ, Holt L (In Press). Nature, extent and ecological implications of night-time light from road vehicles. Journal of Applied Ecology
Gaston KJ (In Press). Nighttime ecology: the ‘nocturnal problem’ revisited. American Naturalist
Gaston K, Ackermann S, Bennie J, Cox D, Phillips B, Sanchez De Miguel A, Sanders D (In Press). Pervasiveness of biological impacts of artificial light at night. Integrative and Comparative Biology
Phillips B, Navaratnam A, Hooper J, Bullock J, Osborne J, Gaston K (In Press). Road verge extent and habitat composition across Great Britain. Landscape and Urban Planning
Cox D, Bennie J, Casalegno S, Hudson HL, Anderson K, Gaston KJ (In Press). Skewed contributions of individual trees to indirect nature experiences. Landscape and Urban Planning
Garrett J, Donald PF, Gaston KJ (In Press). Skyglow extends into the world’s Key Biodiversity Areas. Animal Conservation
Phillips BB, Bullock JM, Osborne JL, Gaston K (In Press). Spatial extent of road pollution: a national analysis. Science of the Total Environment
Shanahan DF, Fuller RA, Bush R, Lin BB, Gaston KJ (In Press). The health benefits of urban nature: how much do we need?.
Sanchez De Miguel A, Kyba C, Zamorano J, Gallego J, Gaston K (In Press). The nature of the diffuse light near cities detected in
nighttime satellite imagery. Scientific Reports
Soga M, Gaston K (In Press). Towards a unified understanding of human-nature interactions. Nature Sustainability
Anderson K, Hancock S, Casalegno S, Griffiths A, Griffiths D, Sargent F, Macallum J, Cox DTC, Gaston KJ (In Press). Visualising the urban green volume: Exploring LiDAR voxels with tangible technologies and virtual models.
Landscape and Urban PlanningAbstract:
Visualising the urban green volume: Exploring LiDAR voxels with tangible technologies and virtual models
The distribution of vegetation within urban zones is well understood to be important for delivery of a range of ecosystem services. While urban planners and human geographers are conversant with methodologies
for describing and exploring the volumetric nature of built spaces there is less research that has developed imaginative ways of visualising the complex spatial and volumetric structure of urban vegetation from the treetops to the ground. Using waveform LiDAR data to measure the three-dimensional nature of the urban greenspace, we explore different ways of virtually, and tangibly engaging with volumetric models describing the 3D
distribution of urban vegetation. Using waveform LiDAR data processed into voxels (volumetric pixels) and experimenting with a variety of creative approaches to visualise the volumetric nature of the data, we describe the
development of new methods for mapping the urban green volume, using a combination of Geographic Information Systems (GIS), Minecraft, 3D printing and Computer Numerical Control (CNC) milling processes. We
demonstrate how such methodologies can be used to reveal and explore the complex nature of the urban green volume. We also describe the outcome of using these models to engage diverse audiences with the volumetric data. We explain how the products could be used readily by a range of urban researchers and stakeholders: from town and city councils, to architects and ecologists.
Abstract.
Gaston KJ, Gardner AS, Cox DTC (2023). Anthropogenic changes to the nighttime environment.
BioScience,
73(4), 280-290.
Abstract:
Anthropogenic changes to the nighttime environment
Abstract
. How the relative impacts of anthropogenic pressures on the natural environment vary between different taxonomic groups, habitats, and geographic regions is increasingly well established. By contrast, the times of day at which those pressures are most forcefully exerted or have greatest influence are not well understood. The impact on the nighttime environment bears particular scrutiny, given that for practical reasons (e.g. researchers themselves belong to a diurnal species), most studies on the impacts of anthropogenic pressures are conducted during the daytime on organisms that are predominantly day active or in ways that do not differentiate between daytime and nighttime. In the present article, we synthesize the current state of knowledge of impacts of anthropogenic pressures on the nighttime environment, highlighting key findings and examples. The evidence available suggests that the nighttime environment is under intense stress across increasing areas of the world, especially from nighttime pollution, climate change, and overexploitation of resources.
Abstract.
Bullough K, Gaston KJ, Troscianko J (2023). Artificial light at night causes conflicting behavioural and morphological defence responses in a marine isopod.
Proc Biol Sci,
290(2000).
Abstract:
Artificial light at night causes conflicting behavioural and morphological defence responses in a marine isopod.
Encroachment of artificial light at night (ALAN) into natural habitats is increasingly recognized as a major source of anthropogenic disturbance. Research focussed on variation in the intensity and spectrum of ALAN emissions has established physiological, behavioural and population-level effects across plants and animals. However, little attention has been paid to the structural aspect of this light, nor how combined morphological and behavioural anti-predator adaptations are affected. We investigated how lighting structure, background reflectance and the three-dimensional properties of the environment combined to affect anti-predator defences in the marine isopod Ligia oceanica. Experimental trials monitored behavioural responses including movement and background choice, and also colour change, a widespread morphological anti-predator mechanism little considered in relation to ALAN exposure. We found that behavioural responses of isopods to ALAN were consistent with classic risk-aversion strategies, being particularly exaggerated under diffuse lighting. However, this behaviour was disconnected from optimal morphological strategies, as diffuse light caused isopods to become lighter coloured while seeking out darker backgrounds. Our work highlights the potential for the structure of natural and artificial light to play a key role in behavioural and morphological processes likely to affect anti-predator adaptations, survival, and ultimately wider ecological effects.
Abstract.
Author URL.
Jolkkonen J, Gaston KJ, Troscianko J (2023). Artificial lighting affects the landscape of fear in a widely distributed shorebird.
Communications Biology,
6(1).
Abstract:
Artificial lighting affects the landscape of fear in a widely distributed shorebird
AbstractFear influences almost all aspects of a prey species’ behaviour, such as its foraging and movement, and has the potential to cause trophic cascades. The superior low-light vision of many predators means that perceived predation risk in prey is likely to be affected by light levels. The widespread and increasing intensity of artificial light at night is therefore likely to interfere with this nocturnal visual arms race with unknown behavioural and ecological consequences. Here we test how the fear of predation perceived by wintering Eurasian curlew foraging on tidal flats is influenced by lighting. We quantified flight initiation distance (FID) of individuals under varying levels of natural and artificial illumination. Our results demonstrate that FID is significantly and substantially reduced at low light levels and increases under higher intensity illumination, with artificial light sources having a greater influence than natural sources. Contrary to the sensory-limitation hypothesis, the curlews’ unwillingness to take flight in low-light appears to reflect the risks posed by low-light flight, and a desire to remain on valuable foraging grounds. These findings demonstrate how artificial light can shape the landscape of fear, and how this interacts with optimal foraging decisions, and the costs of taking flight.
Abstract.
Delahay RJ, Sherman D, Soyalan B, Gaston KJ (2023). Biodiversity in residential gardens: a review of the evidence base.
Biodiversity and ConservationAbstract:
Biodiversity in residential gardens: a review of the evidence base
AbstractResidential gardens are a principal component of urban green infrastructure throughout the world and their potential positive contributions to biodiversity are increasingly recognised. But the characteristics of gardens reflect the needs, values and interests of individual households. The present review summarises evidence from studies of garden biodiversity published in the scientific literature, describes major themes and identifies important knowledge gaps. A search of the Web of Science database identified 408 published articles on the biodiversity of residential gardens (1981–2022), with numbers increasing over time and a strong bias towards Europe (32.1%) and North America (23.8%). Plants and invertebrates were most frequently studied, and species diversity was often correlated with garden size and habitat complexity. Botanic composition and vegetation cover were often positively associated with the diversity and abundance of fauna. Non-native plants contributed substantially to garden plant diversity and evidence from some studies indicated benefits to other species linked to their functional attributes. Intensive management including frequent lawn mowing, fertiliser and pesticide application, and a more formal, ‘neater’ garden appearance were often associated with reduced biodiversity. However, results varied amongst studies, for example in relation to the impacts of mowing frequency on lawn diversity. There was a general paucity of experimental evidence on the impacts of different management regimes on garden biodiversity and few replicated experimental tests of recommended ‘wildlife-friendly practices’. Several studies identified the importance of connectivity amongst gardens and with other green infra-structure for species dispersal and ecosystem functioning. Emerging threats to garden biodiversity include their replacement by development, conversion to hard surfaces and declining plot sizes. Managing these challenges and maximising the biodiversity value of residential gardens requires greater engagement from policymakers and planners, and partnerships between public bodies and private households to co-ordinate local initiatives.
Abstract.
Soga M, Gaston KJ (2023). Global synthesis reveals heterogeneous changes in connection of humans to nature. One Earth, 6(2), 131-138.
Cox DTC, Baker DJ, Gardner AS, Gaston KJ (2023). Global variation in unique and redundant mammal functional diversity across the daily cycle.
Journal of Biogeography,
50(4), 629-640.
Abstract:
Global variation in unique and redundant mammal functional diversity across the daily cycle
AbstractAimOrganisms primarily influence ecosystems through their functional traits when they are physically active. Following the nocturnal bottleneck, the expansion of mammals into the daytime expanded mammalian functional diversity (FD), however there is also notable overlap in trait space across diel niches leading to redundant FD. We explore how the unique and redundant contribution of each diel niche varies spatially and in relation to natural variation in light and temperature.LocationGlobal.TaxonExtant mammals.MethodsBased on five major functional traits (body mass, litter size, diet breadth, foraging strata, habitat breadth) for 5033 extant terrestrial mammals, we determine biogeographical variation in nocturnal, crepuscular, cathemeral and diurnal FD. We calculate the proportion of mammalian FD that is unique to each diel niche, and the proportion that is redundant across the daily cycle.ResultsThe diversification of mammals into the daytime resulted in the creation of new FD (28.5% of FD is not nocturnal; Lower Quartile 17.3%; Upper Quartile 38.2%). Most of this expansion occurred at higher latitudes where uniquely cathemeral FD dominates (>55°N, 41.1% of mammalian FD; Lower Quartile 33.3%, Upper Quartile 53.6%), associated with fewer hours of biologically useful moonlight and daylight. Where there are more hours of biologically useful daylight, unique diurnal FD is common. However, more than half of non‐nocturnal FD is redundant, increasing ecosystem stability as different species carry out similar functions at different times of day, and suggesting that many mammals have not diversified far from their nocturnal ancestors.Main conclusionsOver much of the land surface more than a half of FD only occurs at night, underscoring the importance of nocturnal mammals for ecosystems. Understanding diel variation in FD not only informs on community structure and ecosystem function but also on ecosystem functional persistence in the Anthropocene, with pressures at night being particularly concerning.
Abstract.
Gaston KJ, Phillips BB, Soga M (2023). Personalised ecology and the future of biodiversity.
Cambridge Prisms: Extinction,
1Abstract:
Personalised ecology and the future of biodiversity
Abstract
. The future of biodiversity lies not just in the strategies and mechanisms by which ecosystems and species are practically best protected from anthropogenic pressures. It lies also, and perhaps foremost, in the many billions of decisions that people make that, intentionally or otherwise, shape their impact on nature and the conservation policies and interventions that are implemented. Personalised ecology – the set of direct sensory interactions that each of us has with nature – is one important consideration in understanding the decisions that people make. Indeed, it has long been argued that people’s personalised ecologies have powerful implications, as captured in such concepts as biophilia, extinction of experience and shifting baselines. In this paper, we briefly review the connections between personalised ecology and the future of biodiversity, and the ways in which personalised ecologies might usefully be enhanced to improve that future.
Abstract.
Coetzee BWT, Smit IPJ, Ackermann S, Gaston KJ (2023). The impacts of artificial light at night in Africa: Prospects for a research agenda.
South African Journal of Science,
119(3/4).
Abstract:
The impacts of artificial light at night in Africa: Prospects for a research agenda
Artificial light at night (ALAN) has increasingly been recognised as one of the world’s most pernicious global change drivers that can negatively impact both human and environmental health. However, when compared to work elsewhere, the dearth of research into the mapping, expansion trajectories and consequences of ALAN in Africa is a surprising oversight by its research community. Here, we outline the scope of ALAN research and elucidate key areas in which the African research community could usefully accelerate work in this field. These areas particularly relate to how African conditions present underappreciated caveats to the quantification of ALAN, that the continent experiences unique challenges associated with ALAN, and that these also pose scientific opportunities to understanding its health and environmental impacts. As Africa is still relatively free from the high levels of ALAN found elsewhere, exciting possibilities exist to shape the continent’s developmental trajectories to mitigate ALAN impacts and help ensure the prosperity of its people and environment.
Abstract.
Baker DJ, Maclean IMD, Goodall M, Gaston KJ (2022). Correlations between spatial sampling biases and environmental niches affect species distribution models.
Global Ecology and Biogeography,
31(6), 1038-1050.
Abstract:
Correlations between spatial sampling biases and environmental niches affect species distribution models
AbstractAimSpatial sampling biases in biodiversity data arise because of complex interactions between geography, species characteristics and human behaviour, including preferences for or against particular species or habitats; biases are therefore not necessarily independent of the environmental niches of species. We evaluate when correlations between spatial sampling biases and environmental niches are likely to affect species distribution models (SDMs) developed both with and without attempts to correct these biases.InnovationA virtual species and virtual ecologist framework was used to simulate biodiversity data with either no spatial sampling bias or biases that were correlated (positively or negatively) with one of the environmental variables used to define the environmental niches of the species. The environmental variables used to define the species niche were simulated with spatial autocorrelation operating at multiple spatial scales. Virtual samples were then used to model species distributions, with models evaluated based on their ability to rank the suitability of sites correctly.Main conclusionsCorrelations between spatial sampling bias and environmental niches frequently reduced the rank correlation of model predictions, but the relative importance of these effects varied with species type (greater decline in rank correlation as the environmental niche broadens) and data type (models built using detection/non‐detection data were less affected than those using detection‐only data). Bias‐correction effectiveness varied depending on the structure of the spatial bias but was also highly variable across methods and dependent on data type. The implications of these results are that spatial sampling bias is a greater concern for SDMs where: (1) the distribution of effort is non‐random with respect to an environmental gradient thought to be correlated with a species’ distribution; (2) the species being modelled has a broad environmental niche; and (3) the data for modelling contain only information on detections (i.e. presence only).
Abstract.
Sánchez de Miguel A, Bennie J, Rosenfeld E, Dzurjak S, Gaston KJ (2022). Environmental risks from artificial nighttime lighting widespread and increasing across Europe.
Science Advances,
8(37).
Abstract:
Environmental risks from artificial nighttime lighting widespread and increasing across Europe
The nighttime environment of much of Earth is being changed rapidly by the introduction of artificial lighting. While data on spatial and temporal variation in the intensity of artificial lighting have been available at a regional and global scale, data on variation in its spectral composition have only been collected for a few locations, preventing variation in associated environmental and human health risks from being mapped. Here, we use imagery obtained using digital cameras by astronauts on the International Space Station to map variation in the spectral composition of lighting across Europe for 2012–2013 and 2014–2020. These show a regionally widespread spectral shift, from that associated principally with high-pressure sodium lighting to that associated with broad white light-emitting diodes and with greater blue emissions. Reexpressing the color maps in terms of spectral indicators of environmental pressures, we find that this trend is widely increasing the risk of harmful effects to ecosystems.
Abstract.
Cox DTC, Gardner AS, Gaston KJ (2022). Global and regional erosion of mammalian functional diversity across the diel cycle.
Science Advances,
8(32).
Abstract:
Global and regional erosion of mammalian functional diversity across the diel cycle
Biodiversity is declining worldwide. When species are physically active (i.e. their diel niche) may influence their risk of becoming functionally extinct. It may also affect how species losses affect ecosystems. For 5033 terrestrial mammals, we predict future changes to diel global and local functional diversity through a gradient of progressive functional extinction scenarios of threatened species. Across scenarios, diurnal species were at greater risk of becoming functionally extinct than nocturnal, crepuscular, and cathemeral species, resulting in deep functional losses in global diurnal trait space. Redundancy (species with similar roles) will buffer global nocturnal functional diversity; however, across the land surface, losses will mostly occur among functionally dispersed species (species with distinct roles). Functional extinctions will constrict boundaries of cathemeral trait space as megaherbivores, and arboreal foragers are lost. Variation in the erosion of functional diversity across the daily cycle will likely profoundly affect the partitioning of ecosystem functioning between night and day.
Abstract.
Fish R, Chan KMA, Maller C, Hails RS, Aime E, Gaston KJ (2022). People and nature: the emerging signature of a relational journal.
PEOPLE AND NATURE,
4(3), 592-595.
Author URL.
Chang C-C, Cox DTC, Fan Q, Nghiem TPL, Tan CLY, Oh RRY, Lin BB, Shanahan DF, Fuller RA, Gaston KJ, et al (2022). People's desire to be in nature and how they experience it are partially heritable.
PLoS Biol,
20(2).
Abstract:
People's desire to be in nature and how they experience it are partially heritable.
Nature experiences have been linked to mental and physical health. Despite the importance of understanding what determines individual variation in nature experience, the role of genes has been overlooked. Here, using a twin design (TwinsUK, number of individuals = 2,306), we investigate the genetic and environmental contributions to a person's nature orientation, opportunity (living in less urbanized areas), and different dimensions of nature experience (frequency and duration of public nature space visits and frequency and duration of garden visits). We estimate moderate heritability of nature orientation (46%) and nature experiences (48% for frequency of public nature space visits, 34% for frequency of garden visits, and 38% for duration of garden visits) and show their genetic components partially overlap. We also find that the environmental influences on nature experiences are moderated by the level of urbanization of the home district. Our study demonstrates genetic contributions to individuals' nature experiences, opening a new dimension for the study of human-nature interactions.
Abstract.
Author URL.
Soga M, Gaston KJ (2022). The dark side of nature experience: Typology, dynamics and implications of negative sensory interactions with nature.
People and Nature,
4(5), 1126-1140.
Abstract:
The dark side of nature experience: Typology, dynamics and implications of negative sensory interactions with nature
Abstract
The human health benefits of direct sensory interactions with nature (hereafter direct human–nature interactions) are increasingly recognised. However, these interactions can also have various negative health and well‐being impacts on people, some of which may be severe. Compared to positive ones, there has been relatively little investigation of such negative direct human–nature interactions beyond the medical literature, and what has been done is widely scattered across disciplines.
Here, we provide an overview of the typology, characteristics and dynamics of negative direct sensory interactions with nature and suggest management implications and future research directions.
We highlight the breadth of forms that negative direct human–nature interactions occur, and evidence that the incidences of some have recently grown rapidly in many parts of the world.
Our review also suggests that more intense negative direct human–nature interactions can sometimes occur simultaneously or sequentially with more positive ones, and there may be trade‐offs between the two.
Such serious implications highlight the importance of focusing research and public policy on improving the understanding of negative direct human–nature interactions, taking a more balanced view of the benefits and costs of nature experiences, and developing appropriate mitigation strategies.
Read the free Plain Language Summary for this article on the Journal blog.
Abstract.
Cox D, Gardner A, Gaston K (2021). Diel niche variation in mammals associated with expanded trait space. Nature Communications, 12, 1753-1753.
Robles J, Zamorano J, Pascual S, Sánchez de Miguel A, Gallego J, Gaston KJ (2021). Evolution of brightness and color of the night sky in madrid.
Remote Sensing,
13(8).
Abstract:
Evolution of brightness and color of the night sky in madrid
Major schemes to replace other streetlight technologies with Light-Emitting Diode (LED) lamps are being undertaken across much of the world. This is predicted to have important conse-quences for nighttime sky brightness and color. Here, we report the results of a long-term study of these characteristics focused on the skies above Madrid. The sky brightness and color monitoring station at Universidad Complutense de Madrid (inside the city) collected Johnson B, V, and R sky brightness data, Sky Quality Meter (SQM), and Telescope Encoder Sky Sensor-WiFi (TESS-W) broad-band photometry throughout the night, every night between 2010–2020. Our analysis includes a data filtering process that can be used with other similar sky brightness monitoring data. Major changes in sky brightness and color took place during 2015–2016, when a sizable fraction of the streetlamps in Madrid changed from High-Pressure Sodium (HPS) to LEDs. The sky brightness detected in the Johnson B band darkened by 14% from 2011 to 2015 and brightened by 32% from 2015 to 2019.
Abstract.
Oh RYR, Fielding KS, Nghiem TPL, Chang C, Shanahan DF, Gaston KJ, Carrasco RL, Fuller RA (2021). Factors influencing nature interactions vary between cities and types of nature interactions.
People and Nature,
3(2), 405-417.
Abstract:
Factors influencing nature interactions vary between cities and types of nature interactions
Abstract
There is mounting concern that people living more urbanised, modern lifestyles have fewer and lower quality interactions with nature, and therefore have limited access to the associated health and well‐being benefits. Yet, variation in the different types of nature interactions and the factors that influence these interactions across populations are poorly understood.
We compared four types of nature interactions by administering surveys across two cities that differ markedly in urbanisation pattern and population density—Singapore and Brisbane—: (a) indirect (viewing nature through a window at work or at home); (b) incidental (spending time in nature as part of work); (c) intentional interactions in gardens; and (d) intentional interactions in public urban greenspace.
Our results show that Singapore respondents spent about half as much time (25.8 hr/week) interacting with nature as Brisbane respondents (52.3 hr/week), and indirect interactions were the most prevalent across both cities.
Nature orientation, age, income and gender significantly predicted the duration of nature interactions in both cities, while self‐reported health, education and ethnicity additionally predicted the duration of nature interactions only for Brisbane. Also, the relationship(s) between each factor and duration could differ in direction and effect size between the types of nature interactions.
As such, we conclude that there is much local variation in the dynamics of interactions between people and nature, and that focused studies are needed to develop effective interventions addressing declines in nature interactions in different locations.
A free Plain Language Summary can be found within the Supporting Information of this article.
Abstract.
Sánchez de Miguel A, Bennie J, Rosenfeld E, Dzurjak S, Gaston KJ (2021). First Estimation of Global Trends in Nocturnal Power Emissions Reveals Acceleration of Light Pollution.
Remote Sensing,
13(16), 3311-3311.
Abstract:
First Estimation of Global Trends in Nocturnal Power Emissions Reveals Acceleration of Light Pollution
The global spread of artificial light is eroding the natural night-time environment. The estimation of the pattern and rate of growth of light pollution on multi-decadal scales has nonetheless proven challenging. Here we show that the power of global satellite observable light emissions increased from 1992 to 2017 by at least 49%. We estimate the hidden impact of the transition to solid-state light-emitting diode (LED) technology, which increases emissions at visible wavelengths undetectable to existing satellite sensors, suggesting that the true increase in radiance in the visible spectrum may be as high as globally 270% and 400% on specific regions. These dynamics vary by region, but there is limited evidence that advances in lighting technology have led to decreased emissions.
Abstract.
Phillips B, Bullock J, Gaston K, Hudson-Edwards K, Bamford M, Cruse D, Dicks L, Falagan C, Wallace C, Osborne J, et al (2021). Impacts of multiple pollutants on pollinator activity in road verges. Journal of Applied Ecology
Soga M, Evans MJ, Cox DTC, Gaston KJ (2021). Impacts of the COVID-19 pandemic on human–nature interactions: Pathways, evidence and implications.
People and Nature,
3(3), 518-527.
Abstract:
Impacts of the COVID-19 pandemic on human–nature interactions: Pathways, evidence and implications
The coronavirus (COVID-19) pandemic and the global response have dramatically changed people's lifestyles in much of the world. These major changes, as well as the associated changes in impacts on the environment, can alter the dynamics of the direct interactions between humans and nature (hereafter human–nature interactions) far beyond those concerned with animals as sources of novel human coronavirus infections. There may be a variety of consequences for both people and nature. Here, we suggest a conceptual framework for understanding how the COVID-19 pandemic might affect the dynamics of human–nature interactions. This highlights three different, but not mutually exclusive, pathways: changes in (a) opportunity, (b) capability and (c) motivation. Through this framework, we also suggest that there are several feedback loops by which changes in human–nature interactions induced by the COVID-19 pandemic can lead to further changes in these interactions such that the impacts of the pandemic could persist over the long term, including after it has ended. The COVID-19 pandemic, which has had the most tragic consequences, can also be viewed as a ‘global natural experiment’ in human–nature interactions that can provide unprecedented mechanistic insights into the complex processes and dynamics of these interactions and into possible strategies to manage them to best effect. A free Plain Language Summary can be found within the Supporting Information of this article.
Abstract.
Lin BB, Ossola A, Alberti M, Andersson E, Bai X, Dobbs C, Elmqvist T, Evans KL, Frantzeskaki N, Fuller RA, et al (2021). Integrating solutions to adapt cities for climate change.
The Lancet Planetary Health,
5(7), e479-e486.
Abstract:
Integrating solutions to adapt cities for climate change
Record climate extremes are reducing urban liveability, compounding inequality, and threatening infrastructure. Adaptation measures that integrate technological, nature-based, and social solutions can provide multiple co-benefits to address complex socioecological issues in cities while increasing resilience to potential impacts. However, there remain many challenges to developing and implementing integrated solutions. In this Viewpoint, we consider the value of integrating across the three solution sets, the challenges and potential enablers for integrating solution sets, and present examples of challenges and adopted solutions in three cities with different urban contexts and climates (Freiburg, Germany; Durban, South Africa; and Singapore). We conclude with a discussion of research directions and provide a road map to identify the actions that enable successful implementation of integrated climate solutions. We highlight the need for more systematic research that targets enabling environments for integration; achieving integrated solutions in different contexts to avoid maladaptation; simultaneously improving liveability, sustainability, and equality; and replicating via transfer and scale-up of local solutions. Cities in systematically disadvantaged countries (sometimes referred to as the Global South) are central to future urban development and must be prioritised. Helping decision makers and communities understand the potential opportunities associated with integrated solutions for climate change will encourage urgent and deliberate strides towards adapting cities to the dynamic climate reality.
Abstract.
Hall K, Robert T, Gaston K, Hempel De Ibarra N (2021). Onset of morning activity in bumblebee foragers under natural low light conditions.
Ecology and EvolutionAbstract:
Onset of morning activity in bumblebee foragers under natural low light conditions
Foraging on flowers in low light at dusk and dawn comes at an additional cost for insect pollinators with diurnal vision. Nevertheless, some species are known to be frequently active at these times. To explore how early and under which light levels colonies of bumblebees, Bombus terrestris, initiate their foraging activity, we tracked foragers of different body sizes using RFID over 5 consecutive days during warm periods of the flowering season. Bees that left the colony at lower light levels and earlier in the day were larger in size. This result extends the evidence for alloethism in bumblebees and shows that foragers differ in their task specialization depending on body size. By leaving the colony earlier to find and exploit flowers in low light, larger‐sized foragers are aided by their more sensitive eyes and can effectively increase their contributions to the colony's food influx. The decision to leave the colony early seems to be further facilitated by knowledge about profitable food resources in specific locations. We observed that experience accrued over many foraging flights determined whether a bee started foraging under lower light levels and earlier in the morning. Larger‐sized bees were not more experienced than smaller‐sized bees, confirming earlier observations of wide size ranges among active foragers. Overall, we found that most foragers left at higher light levels when they could see well and fly faster. Nevertheless, a small proportion of foragers left the colony shortly after the onset of dawn when light levels were below 10 lux. Our observations suggest that bumblebee colonies have the potential to balance the benefits of deploying large‐sized or experienced foragers during dawn against the risks and costs of foraging under low light by regulating the onset of their activity at different stages of the colony's life cycle and in changing environmental conditions.
Abstract.
Lockett MT, Jones TM, Elgar MA, Gaston KJ, Visser ME, Hopkins GR (2021). Urban street lighting differentially affects community attributes of airborne and ground‐dwelling invertebrate assemblages.
Journal of Applied Ecology,
58(10), 2329-2339.
Abstract:
Urban street lighting differentially affects community attributes of airborne and ground‐dwelling invertebrate assemblages
Abstract
The introduction of artificial light at night (ALAN) into natural and urbanised landscapes is a known and highly pervasive disruptor of invertebrate communities. However, the effect of variation in intensity and spectra of ALAN on invertebrate communities inhabiting different spatial niches is little understood. Further, the remarkable ability of ALAN to continue to disrupt biodiversity even in chronically illuminated urban landscapes is not often acknowledged.
Here, we simultaneously sampled airborne and ground‐dwelling invertebrate assemblages under and between urban street lights to explore the effects on community composition and abundance of (a) proximity to decadal (i.e. long‐illuminated) nocturnal street lighting and (b) variation in the spectral output of light.
The two assemblages responded differently. For airborne invertebrates, night‐time abundance doubled, and night‐time assemblage composition was significantly different for traps under, compared with between, street lights. These differences in abundance were not affected by street light intensity, and were absent in day samples, suggesting that even weak ALAN may be causing short‐term redistribution of nocturnal invertebrates. Further, the abundance (but not composition) effects of ALAN on airborne invertebrates increased when the street lights emitted a higher proportion of short‐wavelength light.
In contrast, for ground‐dwelling invertebrates, we found only marginal effects of proximity and spectrum of lighting on abundance and no effect on assemblage composition. However, more intense street lighting reduced abundance and altered composition at traps both under and between lights.
Synthesis and Applications. Public lighting managers must consider ALAN impacts on invertebrate communities not only when introducing ALAN to naïve environments, but also when changing lighting in areas that are highly urbanised and exposed to decades of ALAN. Further, lighting proposals and environmental monitoring of invertebrate communities must take into account the effects on both ground‐dwelling and airborne assemblages, as these may respond very differently to the presence, intensity and spectrum of ALAN.
Abstract.
Gaston KJ, Soga M (2020). Extinction of experience: the need to be more specific.
People and Nature,
2(3), 575-581.
Abstract:
Extinction of experience: the need to be more specific
Abstract
Extinction of experience, the progressive loss of human–nature interactions, may prove to be one of the key environmental concepts of our times. Not only does this loss reduce the important benefits that people gain from these interactions, but it may also undermine their support for pro‐biodiversity policies and management actions, and thus play an important role in shaping the future of biodiversity.
Here, to help improve understanding, encourage a more consistent approach and highlight research gaps, we consider some of the key features of the concept of extinction of experience, contentions that these have caused and propose some solutions.
We focus particularly on the importance of (a) the definition of nature employed; (b) whether direct or other human–nature interactions are considered; (c) the differences between the loss and the extinction of experience; (d) the timing of the loss of interactions that is considered and (e) the difference between human–nature interactions and human–nature experiences.
Differentiating between narrow and broad senses of nature, between childhood and lifelong timings, and between interactions and experiences leads to a typology of eight different forms of extinction of experience. Such a classification can be useful for targeting research, furthering understanding of the processes and dynamics of the extinction of experience, and developing policies to reduce this phenomenon and minimize its negative consequences.
A free Plain Language Summary can be found within the Supporting Information of this article.
Abstract.
Edmondson JL, Childs DZ, Dobson MC, Gaston KJ, Warren PH, Leake JR (2020). Feeding a city – Leicester as a case study of the importance of allotments for horticultural production in the UK.
Science of the Total Environment,
705Abstract:
Feeding a city – Leicester as a case study of the importance of allotments for horticultural production in the UK
The process of urbanization has detached a large proportion of the global population from involvement with food production. However, there has been a resurgence in interest in urban agriculture and there is widespread recognition by policy-makers of its potential contribution to food security. Despite this, there is little data on urban agricultural production by non-commercial small-scale growers. We combine citizen science data for self-provisioning crop yields with field-mapping and GIS-based analysis of allotments in Leicester, UK, to provide an estimate of allotment fruit and vegetable production at a city-scale. In addition, we examine city-scale changes in allotment land provision on potential crop production over the past century. The average area of individual allotment plots used to grow crops was 52%. Per unit area yields for the majority of crops grown in allotments were similar to those of UK commercial horticulture. We estimate city-wide allotment production of >1200 t of fruit and vegetables and 200 t of potatoes per annum, equivalent to feeding >8500 people. If the 13% of plots that are completely uncultivated were used this could increase production to >1400 t per annum, feeding ~10,000 people, however this production may not be located in areas where there is greatest need for increased access to fresh fruits and vegetables. The citywide contribution of allotment cultivation peaked in the 1950s when 475 ha of land was allotments, compared to 97 ha currently. This suggests a decline from >45,000 to
Abstract.
Cox DTC, Maclean IMD, Gardner AS, Gaston KJ (2020). Global variation in diurnal asymmetry in temperature, cloud cover, specific humidity and precipitation and its association with leaf area index.
Global Change Biology,
26(12), 7099-7111.
Abstract:
Global variation in diurnal asymmetry in temperature, cloud cover, specific humidity and precipitation and its association with leaf area index
AbstractThe impacts of the changing climate on the biological world vary across latitudes, habitats and spatial scales. By contrast, the time of day at which these changes are occurring has received relatively little attention. As biologically significant organismal activities often occur at particular times of day, any asymmetry in the rate of change between the daytime and night‐time will skew the climatic pressures placed on them, and this could have profound impacts on the natural world. Here we determine global spatial variation in the difference in the mean annual rate at which near‐surface daytime maximum and night‐time minimum temperatures and mean daytime and mean night‐time cloud cover, specific humidity and precipitation have changed over land. For the years 1983–2017, we derived hourly climate data and assigned each hour as occurring during daylight or darkness. In regions that showed warming asymmetry of >0.5°C (equivalent to mean surface temperature warming during the 20th century) we investigated corresponding changes in cloud cover, specific humidity and precipitation. We then examined the proportional change in leaf area index (LAI) as one potential biological response to diel warming asymmetry. We demonstrate that where night‐time temperatures increased by >0.5°C more than daytime temperatures, cloud cover, specific humidity and precipitation increased. Conversely, where daytime temperatures increased by >0.5°C more than night‐time temperatures, cloud cover, specific humidity and precipitation decreased. Driven primarily by increased cloud cover resulting in a dampening of daytime temperatures, over twice the area of land has experienced night‐time warming by >0.25°C more than daytime warming, and has become wetter, with important consequences for plant phenology and species interactions. Conversely, greater daytime relative to night‐time warming is associated with hotter, drier conditions, increasing species vulnerability to heat stress and water budgets. This was demonstrated by a divergent response of LAI to warming asymmetry.
Abstract.
Kehoe R, Sanders D, Cruse D, Silk M, Gaston KJ, Bridle JR, van Veen F (2020). Longer photoperiods through range shifts and artificial light lead to a destabilizing increase in host–parasitoid interaction strength.
Journal of Animal Ecology,
89(11), 2508-2516.
Abstract:
Longer photoperiods through range shifts and artificial light lead to a destabilizing increase in host–parasitoid interaction strength
Abstract
Many organisms are experiencing changing daily light regimes due to latitudinal range shifts driven by climate change and increased artificial light at night (ALAN). Activity patterns are often driven by light cycles, which will have important consequences for species interactions.
We tested whether longer photoperiods lead to higher parasitism rates by a day‐active parasitoid on its host using a laboratory experiment in which we independently varied daylength and the presence of ALAN. We then tested whether reduced nighttime temperature tempers the effect of ALAN.
We found that parasitism rate increased with daylength, with ALAN intensifying this effect only when the temperature was not reduced at night. The impact of ALAN was more pronounced under short daylength. Increased parasitoid activity was not compensated for by reduced life span, indicating that increased daylength leads to an increase in total parasitism effects on fitness.
To test the significance of increased parasitism rate for population dynamics, we developed a host–parasitoid model. The results of the model predicted an increase in time‐to‐equilibrium with increased daylength and, crucially, a threshold daylength above which interactions are unstable, leading to local extinctions.
Here we demonstrate that ALAN impact interacts with daylength and temperature by changing the interaction strength between a common day‐active consumer species and its host in a predictable way. Our results further suggest that range expansion or ALAN‐induced changes in light regimes experienced by insects and their natural enemies will result in unstable dynamics beyond key tipping points in daylength.
Abstract.
Gaston KJ (2020). Personalised ecology and detection functions.
People and Nature,
2(4), 995-1005.
Abstract:
Personalised ecology and detection functions
Abstract
Direct interactions with nature are important for people's health, well‐being and support for pro‐nature policies. There is an urgent need better to understand the structure and dynamics of these interactions, and how they differ among individual people, human populations and the communities to which they belong.
The determinants of these interactions have two components. First are the factors that influence whether someone undertakes actions that may lead to interactions with nature (e.g. looking through a window, going for a walk, travelling to the countryside). These factors have attracted significant attention. Second are the factors that influence what nature interactions are obtained when someone is present in a situation in which these could occur. These have received little explicit attention.
One way of formalizing understanding, and identifying gaps in knowledge, of the second group of factors is to consider human–nature interactions in terms of detection functions. Rather than using such functions for the estimation of species abundances, the purpose for which they were originally developed, they can be reorganized as descriptors of influences on people's nature interactions.
This paper considers how the different variables contained within detection functions influence human–nature interactions, and in particular how the number of nature interactions a person has in a given place and time is shaped both by clearly ‘nature’‐associated variables, such as the number of organisms present, and also by variables that are strongly influenced by characteristics of the observer, such as how they use or explore an area and their personal nature detection abilities.
Many issues explored in the context of human–nature interactions are then seen to concern these component variables of detection functions, and approaches to improving the frequency of interactions seen, in effect, to be targeted at affecting change in different ones of these variables.
A free Plain Language Summary can be found within the Supporting Information of this article.
Abstract.
Baker DJ, Maclean IMD, Goodall M, Gaston KJ (2020). Species distribution modelling is needed to support ecological impact assessments.
Journal of Applied Ecology,
58(1), 21-26.
Abstract:
Species distribution modelling is needed to support ecological impact assessments
Abstract
Legislation commonly mandates the mitigation of impacts to biodiversity in planning and development processes, with potential impacts identified through some form of ecological impact assessment. Yet, protections for biodiversity are frequently undermined because the distributions of priority species are poorly known in most locations at the spatial scales required to inform planning decisions (i.e. c. 1–100 ha).
Planning applications are often screened against opportunistic records to determine potential impacts to priority species. However, raw occurrence records provide information only on where a species has been detected and cannot be used to indicate if a species is likely to be absent from a site.
Inferences drawn from these data on the likelihood of a species being present at a site can only be correctly interpreted through an appropriate species distribution modelling (SDM) framework that ensures assumptions about the data and models are formalised and documented. We argue that SDM frameworks must be integrated into ecological impact assessments to improve support for biodiversity protections within planning and development processes.
Biases and uncertainties in opportunistic data create modelling challenges, but recent methodological advances can minimise their impacts on predictions. We advocate co‐production with practitioners of SDM tools, mapping products and best‐practice guidelines specific to planning processes.
Policy implications. The integration of species distribution modelling frameworks into ecological impact assessments will strengthen biodiversity protections in planning and development processes by ensuring methodological transparency and rigour in the interpretation of species occurrence data.
Abstract.
Soga M, Gaston KJ (2020). The ecology of human–nature interactions.
Proceedings of the Royal Society B: Biological Sciences,
287(1918), 20191882-20191882.
Abstract:
The ecology of human–nature interactions
The direct interactions between people and nature are critically important in many ways, with growing attention particularly on their impacts on human health and wellbeing (both positive and negative), on people's attitudes and behaviour towards nature, and on the benefits and hazards to wildlife. A growing evidence base is accelerating the understanding of different forms that these direct human–nature interactions take, novel analyses are revealing the importance of the opportunity and orientation of individual people as key drivers of these interactions, and methodological developments are increasingly making apparent their spatial, temporal and socio-economic dynamics. Here, we provide a roadmap of these advances and identify key, often interdisciplinary, research challenges that remain to be met. We identified several key challenges, including the need to characterize individual people's nature interactions through their life course, to determine in a comparable fashion how these interactions vary across much more diverse geographical, cultural and socio-economic contexts that have been explored to date, and to quantify how the relative contributions of people's opportunity and orientation vary in shaping their nature interactions. A robust research effort, guided by a focus on such unanswered questions, has the potential to yield high-impact insights into the fundamental nature of human–nature interactions and contribute to developing strategies for their appropriate management.
Abstract.
Sutherland WJ, Broad S, Butchart SHM, Clarke SJ, Collins AM, Dicks LV, Doran H, Esmail N, Fleishman E, Frost N, et al (2019). A Horizon Scan of Emerging Issues for Global Conservation in 2019.
Trends Ecol Evol,
34(1), 83-94.
Abstract:
A Horizon Scan of Emerging Issues for Global Conservation in 2019.
We present the results of our tenth annual horizon scan. We identified 15 emerging priority topics that may have major positive or negative effects on the future conservation of global biodiversity, but currently have low awareness within the conservation community. We hope to increase research and policy attention on these areas, improving the capacity of the community to mitigate impacts of potentially negative issues, and maximise the benefits of issues that provide opportunities. Topics include advances in crop breeding, which may affect insects and land use; manipulations of natural water flows and weather systems on the Tibetan Plateau; release of carbon and mercury from melting polar ice and thawing permafrost; new funding schemes and regulations; and land-use changes across Indo-Malaysia.
Abstract.
Author URL.
de Miguel AS, Bará S, Aubé M, Cardiel N, Tapia CE, Zamorano J, Gaston KJ (2019). Evaluating human photoreceptoral inputs from night-time lights using RGB imaging photometry.
Journal of Imaging,
5(4).
Abstract:
Evaluating human photoreceptoral inputs from night-time lights using RGB imaging photometry
Night-time lights interact with human physiology through different pathways starting at the retinal layers of the eye; from the signals provided by the rods; the S-, L- and M-cones; and the intrinsically photosensitive retinal ganglion cells (ipRGC). These individual photic channels combine in complex ways to modulate important physiological processes, among them the daily entrainment of the neural master oscillator that regulates circadian rhythms. Evaluating the relative excitation of each type of photoreceptor generally requires full knowledge of the spectral power distribution of the incoming light, information that is not easily available in many practical applications. One such instance is wide area sensing of public outdoor lighting; present-day radiometers onboard Earth-orbiting platforms with sufficient nighttime sensitivity are generally panchromatic and lack the required spectral discrimination capacity. In this paper, we show that RGB imagery acquired with off-the-shelf digital single-lens reflex cameras (DSLR) can be a useful tool to evaluate, with reasonable accuracy and high angular resolution, the photoreceptoral inputs associated with a wide range of lamp technologies. The method is based on linear regressions of these inputs against optimum combinations of the associated R, G, and B signals, built for a large set of artificial light sources by means of synthetic photometry. Given the widespread use of RGB imaging devices, this approach is expected to facilitate the monitoring of the physiological effects of light pollution, from ground and space alike, using standard imaging technology.
Abstract.
Goettsch B, Durán AP, Gaston KJ (2019). Global gap analysis of cactus species and priority sites for their conservation.
Conserv Biol,
33(2), 369-376.
Abstract:
Global gap analysis of cactus species and priority sites for their conservation.
Knowing how much biodiversity is captured by protected areas (PAs) is important to meeting country commitments to international conservation agreements, such as the Convention on Biological Diversity, and analyzing gaps in species coverage by PAs contributes greatly to improved locating of new PAs and conservation of species. Regardless of their importance, global gap analyses have been conducted only for a few taxonomic groups (e.g. mangroves, corals, amphibians, birds, mammals). We conducted the first global gap analysis for a complete specious plant group, the highly threatened Cactaceae. Using geographic distribution data of 1438 cactus species, we assessed how well the current PA network represents them. We also systematically identified priority areas for conservation of cactus species that met and failed to meet conservation targets accounting for their conservation status. There were 261 species with no coverage by PAs (gap species). A greater percentage of cacti species (18%) lacked protection than mammals (9.7%) and birds (5.6%), and also a greater percentage of threatened cacti species (32%) were outside protected areas than amphibians (26.5%), birds (19.9%), or mammals (16%). The top 17% of the landscape that best captured covered species represented on average 52.9% of species ranges. The priority areas for gap species and the unprotected portion of the ranges of species that only partially met their conservation target (i.e. partial gap) captured on average 75.2% of their ranges, of which 100 were threatened gap species. These findings and knowledge of the threats affecting species provide information that can be used to improve planning for cacti conservation and highlight the importance of assessing the representation of major groups, such as plants, in PAs to determining the performance of the current PA network.
Abstract.
Author URL.
Shanahan DF, Astell-Burt T, Barber EA, Brymer E, Cox DTC, Dean J, Depledge M, Fuller RA, Hartig T, Irvine KN, et al (2019). Nature-Based Interventions for Improving Health and Wellbeing: the Purpose, the People and the Outcomes.
Sports (Basel),
7(6).
Abstract:
Nature-Based Interventions for Improving Health and Wellbeing: the Purpose, the People and the Outcomes.
Engagement with nature is an important part of many people's lives, and the health and wellbeing benefits of nature-based activities are becoming increasingly recognised across disciplines from city planning to medicine. Despite this, urbanisation, challenges of modern life and environmental degradation are leading to a reduction in both the quantity and the quality of nature experiences. Nature-based health interventions (NBIs) can facilitate behavioural change through a somewhat structured promotion of nature-based experiences and, in doing so, promote improved physical, mental and social health and wellbeing. We conducted a Delphi expert elicitation process with 19 experts from seven countries (all named authors on this paper) to identify the different forms that such interventions take, the potential health outcomes and the target beneficiaries. In total, 27 NBIs were identified, aiming to prevent illness, promote wellbeing and treat specific physical, mental or social health and wellbeing conditions. These interventions were broadly categorized into those that change the environment in which people live, work, learn, recreate or heal (for example, the provision of gardens in hospitals or parks in cities) and those that change behaviour (for example, engaging people through organized programmes or other activities). We also noted the range of factors (such as socioeconomic variation) that will inevitably influence the extent to which these interventions succeed. We conclude with a call for research to identify the drivers influencing the effectiveness of NBIs in enhancing health and wellbeing.
Abstract.
Author URL.
Phillips BB, Gaston KJ, Bullock JM, Osborne JL (2019). Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting.
Journal of Applied Ecology,
56(10), 2316-2327.
Abstract:
Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting
Supporting pollinators in agricultural landscapes is important for reversing their global decline. Road verges and hedges are used by pollinators for feeding and reproduction, but few studies consider entire pollinator communities, and it remains unclear how they are distributed across adjacent verges, hedges and fields, or how they are affected by traffic and verge cutting. We surveyed flowers and pollinators, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, we surveyed the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge and the field interior. Road verges and hedges had a much greater flower abundance, flower species richness and pollinator abundance than field interiors. Verge hedges had far less woody cover than field hedges, but greater flower species richness. There were fewer pollinators along verge edges (next to roads) than along verge centres (2–11 m from roads) and fewer pollinators in road verges next to busier roads. Road verges were generally cut once (in summer), and cuttings were never removed. There were substantially fewer flowers and pollinators in road verges that had been cut, even though surveys often took place many weeks after cutting. Synthesis and applications. Road verges and their associated hedges can provide hotspots of resources for pollinators in agricultural landscapes, but their capacity to do so is reduced by heavy traffic and summer verge cutting. We recommend that beneficial management for pollinators should prioritize wider road verges (at least 2 m wide), roads with less traffic, and areas away from the immediate vicinity of the road. Where possible, verge cutting should not be carried out during peak flowering times.
Abstract.
Miguel ASD, Kyba CCM, Zamorano J, Gallego J, Gaston KJ (2019). The nature of the diffuse light near cities detected in nighttime. satellite imagery.
Sci Rep,
10Abstract:
The nature of the diffuse light near cities detected in nighttime. satellite imagery
Diffuse glow has been observed around brightly lit cities in nighttime
satellite imagery since at least the first publication of large scale maps in
the late 1990s. In the literature, this has often been assumed to be an error
related to the sensor, and referred to as "blooming", presumably in relation to
the effect that can occur when using a CCD to photograph a bright source. Here
we show that the effect is not instrumental, but in fact represents a real
detection of light scattered by the atmosphere. Data from the Universidad
Complutense Madrid sky brightness survey are compared to nighttime imagery from
multiple sensors with differing spatial resolutions, and found to be strongly
correlated. These results suggest that it should be possible for a future
space-based imaging radiometer to monitor changes in the diffuse artificial
skyglow of cities.
Abstract.
Author URL.
Gaston KJ, Aimé E, Chan KMA, Fish R, Hails RS, Maller C (2018). <i>People and Nature</i>—A journal of relational thinking. People and Nature, 1(1), 4-5.
Blackburn TM, Gaston KJ (2018). Abundance, biomass and energy use of native and alien breeding birds in Britain.
Biological Invasions,
20(12), 3563-3573.
Abstract:
Abundance, biomass and energy use of native and alien breeding birds in Britain
We quantify the contribution of alien species to the total breeding population numbers, biomass and energy use of an entire taxonomic assemblage at a large spatial scale, using data on British birds from 1997 and 2013. A total of 216 native and 16 alien bird species were recorded as breeding in Great Britain across the two census years. Only 2.8–3.7% of British breeding bird individuals were alien, but alien species co-opted 11.9–13.8% of the energy used by the assemblage, and contributed 19.1–21.1% of assemblage biomass. Neither the population sizes nor biomasses of native and alien species differed, on average, in either census, but alien species biomass is higher than native species biomass for a given population size. Species richness underestimates the potential effects of alien bird species in Britain, which have disproportionately high overall biomass and population energy use. The main driver of these effects is the ring-necked pheasant (Phasianus colchicus), which comprised 74–81% of alien biomass, yet the breeding population of this species is still only a small fraction of the estimated 35 million birds released in the UK in autumn. The biomass of this release exceeds that of the entire breeding avifauna, and suggests that the pheasant should have an important role in structuring the communities in which it is embedded.
Abstract.
Bennie J, Davies TW, Cruse D, Bell F, Gaston KJ (2018). Artificial light at night alters grassland vegetation species composition and phenology.
Journal of Applied Ecology,
55(1), 442-450.
Abstract:
Artificial light at night alters grassland vegetation species composition and phenology
Human settlements and transport networks are growing rapidly worldwide. Since the early 20th century their expansion has been accompanied by increasing illumination of the environment at night, a trend that is likely to continue over the decades to come. Consequently, a growing proportion of the world's ecosystems are exposed to artificial light at night, profoundly altering natural cycles of light and darkness. While in recent years there have been advances in our understanding of the effects of artificial light at night on the behaviour and physiology of animals in the wild, much less is known about the impacts on wild plants and natural or semi-natural vegetation composition. This is surprising, as effects of low-intensity light at night on flowering, phenology and growth form are well known in laboratory and greenhouse studies. In a long-term experimental field study we exposed a semi-natural grassland to artificial light at intensities and wavelengths typical of those experienced by roadside vegetation under street lighting. We found that lighting affected the trajectory of vegetation change, leading to significant differences in biomass and plant cover in the dominant species. Changes in flowering phenology were variable between years, with grass species flowering between 4 days earlier and 12 days later under artificial light. Policy implications. Our results demonstrate that artificial light, at levels equivalent to those in street-lit environments, can affect species composition in semi-natural vegetation. This highlights the importance of considering artificial light as a driver of vegetation change in urban, suburban and semi-natural ecosystems, and where possible, of minimising or excluding artificial light from habitats of conservation importance.
Abstract.
Hopkins GR, Gaston KJ, Visser ME, Elgar MA, Jones TM (2018). Artificial light at night as a driver of evolution across urban–rural landscapes.
Frontiers in Ecology and the Environment,
16(8), 472-479.
Abstract:
Artificial light at night as a driver of evolution across urban–rural landscapes
Light is fundamental to biological systems, affecting the daily rhythms of bacteria, plants, and animals. Artificial light at night (ALAN), a ubiquitous feature of urbanization, interferes with these rhythms and has the potential to exert strong selection pressures on organisms living in urban environments. ALAN also fragments landscapes, altering the movement of animals into and out of artificially lit habitats. Although research has documented phenotypic and genetic differentiation between urban and rural organisms, ALAN has rarely been considered as a driver of evolution. We argue that the fundamental importance of light to biological systems, and the capacity for ALAN to influence multiple processes contributing to evolution, makes this an important driver of evolutionary change, one with the potential to explain broad patterns of population differentiation across urban–rural landscapes. Integrating ALAN's evolutionary potential into urban ecology is a targeted and powerful approach to understanding the capacity for life to adapt to an increasingly urbanized world.
Abstract.
Cox DTC, Hudson HL, Plummer KE, Siriwardena GM, Anderson K, Hancock S, Devine-Wright P, Gaston KJ (2018). Covariation in urban birds providing cultural services or disservices and people.
Journal of Applied Ecology,
55(5), 2308-2319.
Abstract:
Covariation in urban birds providing cultural services or disservices and people
The spatial distributions of biodiversity and people vary across landscapes and are critical to the delivery of ecosystem services and disservices. The high densities of people and often of birds in urban areas lead to frequent human–avian interactions, which can be positive or negative for people's well-being. The identities of the bird species providing these services or disservices tend to be quite different; however, it is unclear how their abundance and richness covary with human population density, and hence with potential recipients of these services and disservices. We surveyed bird populations in 106 tiles (500 × 500 m) across the 174 km2 of an extended urban area in southern England. From the literature, we identified two groups of species: those associated with positive interactions for human well-being and those that display behaviours that are negative for human well-being. We estimated the abundance (adjusted for detection probability) and richness of each group and modelled how they covary with human population density. Aggregation of population estimates for the 35 service and nine disservice species observed revealed 593,128 (95% confidence interval: 541,817–657,046) and 225,491 (200,134–235,066) birds respectively. Across the surveyed tiles, there were 1.09 service and 0.42 disservice birds per person. There was a peaking quadratic relationship between service abundance and human population density, but a negative linear relationship between richness and human density. Conversely, there were positive linear relationships for both abundance and richness of disservice species with human density. The ratio of service to disservice birds shifted from 3.5–1 at intermediate human densities to 1–1 in more densely populated areas. Synthesis and applications. Differences in the distributions of service and disservice species, and the extremely low ratios of birds to people particularly in socioeconomically deprived areas, mean that people there have few opportunities for contact with birds, and the contact they do have is equally likely to be negative as positive for human well-being. We recommend spatial targeting of improvements in green infrastructure, combined with the targeted provisioning of food and nesting places for service species, to promote positive interactions between birds and people.
Abstract.
Soga M, Gaston KJ, Kubo T (2018). Cross-generational decline in childhood experiences of neighborhood flowering plants in Japan.
Landscape and Urban Planning,
174, 55-62.
Abstract:
Cross-generational decline in childhood experiences of neighborhood flowering plants in Japan
People are becoming less likely to experience nature, as we become an increasingly urban society. This progressive disengagement of humans from the natural world, “extinction of experience”, has been viewed both as a key public health issue and one of the most fundamental obstacles to halting global environmental degradation. However, while the existence and significance of the phenomenon are generally agreed upon, it remains surprisingly poorly documented, particularly at large scales and over the longer-term. Here, we report the findings from a web-based questionnaire survey (n = 1147) to assess the extent of people's childhood experiences with neighborhood flowering, plants, one of the most popular and visible group of organisms, in Japan. Results showed that people's levels of childhood experiences with neighborhood flowering plants were positively related to their age: older participants, compared to younger ones, reported higher frequencies of childhood experiences with neighborhood flowering plants. The reported number of neighborhood flowering plant species that participants have directly experienced during childhood was also higher for older participants. Among the 21 flowering plant species we investigated, age-related decline in direct experiences during childhood was observed for 9 species, particularly for those that depend on grasslands (an ecosystem that has been in dramatic decline over the last few decades). Participants’ age and childhood environment (urban vs. rural settings) also had significant effects on their levels of childhood nature experiences. Overall, our results suggest that children's direct connection to neighborhood biodiversity is indeed progressively dwindling, which can have serious implications for public health and biodiversity conservation.
Abstract.
Correa-Cano ME, Goettsch B, Duffy JP, Bennie J, Inger R, Gaston KJ (2018). Erosion of natural darkness in the geographic ranges of cacti.
Scientific Reports,
8(1).
Abstract:
Erosion of natural darkness in the geographic ranges of cacti
Naturally dark nighttime environments are being widely eroded by the introduction of artificial light at night (ALAN). The biological impacts vary with the intensity and spectrum of ALAN, but have been documented from molecules to ecosystems. How globally severe these impacts are likely to be depends in large part on the relationship between the spatio-temporal distribution of ALAN and that of the geographic ranges of species. Here, we determine this relationship for the Cactaceae family. Using maps of the geographic ranges of cacti and nighttime stable light composite images for the period 1992 to 2012, we found that a high percentage of cactus species were experiencing ALAN within their ranges in 1992, and that this percentage had increased by 2012. For almost all cactus species (89.7%) the percentage of their geographic range that was lit increased from 1992-1996 to 2008-2012, often markedly. There was a significant negative relationship between the species richness of an area, and that of threatened species, and the level of ALAN. Cacti could be particularly sensitive to this widespread and ongoing intrusion of ALAN into their geographic ranges, especially when considering the potential for additive and synergistic interactions with the impacts of other anthropogenic pressures.
Abstract.
Sanders D, Gaston KJ (2018). How ecological communities respond to artificial light at night.
Journal of Experimental Zoology Part A: Ecological and Integrative Physiology,
329(8-9), 394-400.
Abstract:
How ecological communities respond to artificial light at night
Many ecosystems worldwide are exposed to artificial light at night (ALAN), from streetlights and other sources, and a wide range of organisms has been shown to respond to this anthropogenic pressure. This raises concerns about the consequences for major ecosystem functions and their stability. However, there is limited understanding of how whole ecological communities respond to ALAN, and this cannot be gained simply by making predictions from observed single species physiological, behavioral, or ecological responses. Research needs to include an important building block of ecological communities, namely the interactions between species that drive ecological and evolutionary processes in ecosystems. Here, we summarize current knowledge about community responses to ALAN and illustrate different pathways and their impact on ecosystem functioning and stability. We discuss that documentation of the impact of ALAN on species interaction networks and trait distributions provides useful tools to link changes in community structure to ecosystem functions. Finally, we suggest several approaches to advance research that will link the diverse impact of ALAN to changes in ecosystems.
Abstract.
Cox DTC, Gaston KJ (2018). Human–nature interactions and the consequences and drivers of provisioning wildlife.
Philosophical Transactions of the Royal Society B: Biological Sciences,
373(1745).
Abstract:
Human–nature interactions and the consequences and drivers of provisioning wildlife
Many human populations are undergoing an extinction of experience, with a progressive decline in interactions with nature. This is a consequence both of a loss of opportunity for, and orientation towards, such experiences. The trend is of concern in part because interactions with nature can be good for human health and wellbeing. One potential means of redressing these losses is through the intentional provision of resources to increase wildlife populations in close proximity to people, thereby increasing the potential for positive human–nature experiences, and thence the array of benefits that can result. In this paper, we review the evidence that these resource subsidies have such a cascade of effects. In some Westernized countries, the scale of provision is extraordinarily high, and doubtless leads to both positive and negative impacts for wildlife. In turn, these impacts often lead to more frequent, reliable and closer human–nature interactions, with a greater variety of species. The consequences for human wellbeing remain poorly understood, although benefits documented in the context of human–nature interactions more broadly seem likely to apply. There are also some important feedback loops that need to be better characterized if resource provisioning is to contribute effectively towards averting the extinction of experience. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.
Abstract.
Dean JH, Shanahan DF, Bush R, Gaston KJ, Lin BB, Barber E, Franco L, Fuller RA (2018). Is nature relatedness associated with better mental and physical health?.
International Journal of Environmental Research and Public Health,
15(7).
Abstract:
Is nature relatedness associated with better mental and physical health?
Nature relatedness is a psychological characteristic with the potential to drive interaction with nature and influence well-being. We surveyed 1538 people in Brisbane, Australia to investigate how nature relatedness varies among socio-demographic groups. We determined whether people with higher nature relatedness reported fewer symptoms of depression, anxiety, stress and better overall health, controlling for potentially confounding socio-demographic and health-related variables. Overall nature relatedness was higher in older people, females, those without children living at home, not working, and people speaking English at home. Aspects of nature relatedness reflecting enjoyment of nature were consistently associated with reduced ill health, consistent with widespread evidence of the health and well-being benefits of experiencing nature. In contrast, aspects of nature relatedness reflecting self-identification with nature, and a conservation worldview, were associated with increased depression, anxiety or stress, after accounting for potential confounding factors. Detailed investigation of causal pathways among nature relatedness, socio-demographic factors and health is warranted, with particular focus on the relationship between stress and nature orientation.
Abstract.
Gaston KJ (2018). Lighting up the nighttime.
Science,
362(6416), 744-746.
Author URL.
Gaston KJ, Soga M, Duffy JP, Garrett JK, Gaston S, Cox DTC (2018). Personalised Ecology.
Trends in Ecology and Evolution,
33(12), 916-925.
Abstract:
Personalised Ecology
The field of ecology has focused on understanding characteristics of natural systems in a manner as free as possible from biases of human observers. However, demand is growing for knowledge of human–nature interactions at the level of individual people. This is particularly driven by concerns around human health consequences due to changes in positive and negative interactions. This requires attention to the biased ways in which people encounter and experience other organisms. Here we define such a ‘personalised ecology’ and discuss its connections to other aspects of the field. We propose a framework of focal research topics, shaped by whether the unit of analysis is a single person, a single population, or multiple populations, and whether a human or nature perspective is foremost.
Abstract.
Davies T, Cowley A, Bennie J, Leyshon C, Inger R, Carter H, Robinson B, Duffy J, Casalegno S, Lambert G, et al (2018). Popular interest in vertebrates does not reflect extinction risk and is associated with bias in conservation investment.
PLoS One,
13(9).
Abstract:
Popular interest in vertebrates does not reflect extinction risk and is associated with bias in conservation investment.
The interrelationship between public interest in endangered species and the attention they receive from the conservation community is the 'flywheel' driving much effort to abate global extinction rates. Yet big international conservation non-governmental organisations have typically focused on the plight of a handful of appealing endangered species, while the public remains largely unaware of the majority. We quantified the existence of bias in popular interest towards species, by analysing global internet search interest in 36,873 vertebrate taxa. Web search interest was higher for mammals and birds at greater risk of extinction, but this was not so for fish, reptiles and amphibians. Our analysis reveals a global bias in popular interest towards vertebrates that is undermining incentives to invest financial capital in thousands of species threatened with extinction. Raising the popular profile of these lesser known endangered and critically endangered species will generate clearer political and financial incentives for their protection.
Abstract.
Author URL.
Gaston KJ, Cox DTC, Canavelli SB, García D, Hughes B, Maas B, Martínez D, Ogada D, Inger R (2018). Population Abundance and Ecosystem Service Provision: the Case of Birds.
BioScience,
68(4), 264-272.
Abstract:
Population Abundance and Ecosystem Service Provision: the Case of Birds
Although there is a diversity of concerns about recent persistent declines in the abundances of many species, the implications for the associated delivery of ecosystem services to people are surprisingly poorly understood. In principle, there are a broad range of potential functional relationships between the abundance of a species or group of species and the magnitude of ecosystem-service provision. Here, we identify the forms these relationships are most likely to take. Focusing on the case of birds, we review the empirical evidence for these functional relationships, with examples of supporting, regulating, and cultural services. Positive relationships between abundance and ecosystem-service provision are the norm (although seldom linear), we found no evidence for hump-shaped relationships, and negative ones were limited to cultural services that value rarity. Given the magnitude of abundance declines among many previously common species, it is likely that there have been substantial losses of ecosystem services, providing important implications for the identification of potential tipping points in relation to defaunation resilience, biodiversity conservation, and human well-being.
Abstract.
Dudley N, Hockings M, Stolton S, Amend T, Badola R, Bianco M, Chettri N, Cook C, Day JC, Dearden P, et al (2018). Priorities for protected area research.
Parks,
24(1), 35-50.
Abstract:
Priorities for protected area research
A hundred research priorities of critical importance to protected area management were identified by a targeted survey of conservation professionals; half researchers and half practitioners. Respondents were selected to represent a range of disciplines, every continent except Antarctica and roughly equal numbers of men and women. The results analysed thematically and grouped as potential research topics as by both practitioners and researchers. Priority research gaps reveal a high interest to demonstrate the role of protected areas within a broader discussion about sustainable futures and if and how protected areas can address a range of conservation and socio-economic challenges effectively. The paper lists the hundred priorities structured under broad headings of management, ecology, governance and social (including political and economic issues) and helps contribute to setting future research agendas.
Abstract.
Soga M, Gaston KJ (2018). Shifting baseline syndrome: causes, consequences, and implications.
Frontiers in Ecology and the Environment,
16(4), 222-230.
Abstract:
Shifting baseline syndrome: causes, consequences, and implications
With ongoing environmental degradation at local, regional, and global scales, people's accepted thresholds for environmental conditions are continually being lowered. In the absence of past information or experience with historical conditions, members of each new generation accept the situation in which they were raised as being normal. This psychological and sociological phenomenon is termed shifting baseline syndrome (SBS), which is increasingly recognized as one of the fundamental obstacles to addressing a wide range of today's global environmental issues. Yet our understanding of this phenomenon remains incomplete. We provide an overview of the nature and extent of SBS and propose a conceptual framework for understanding its causes, consequences, and implications. We suggest that there are several self-reinforcing feedback loops that allow the consequences of SBS to further accelerate SBS through progressive environmental degradation. Such negative implications highlight the urgent need to dedicate considerable effort to preventing and ultimately reversing SBS.
Abstract.
Kehoe RC, Cruse D, Sanders D, Gaston KJ, van Veen FJF (2018). Shifting daylength regimes associated with range shifts alter aphid-parasitoid community dynamics.
Ecology and Evolution,
8(17), 8761-8769.
Abstract:
Shifting daylength regimes associated with range shifts alter aphid-parasitoid community dynamics
With climate change leading to poleward range expansion of species, populations are exposed to new daylength regimes along latitudinal gradients. Daylength is a major factor affecting insect life cycles and activity patterns, so a range shift leading to new daylength regimes is likely to affect population dynamics and species interactions; however, the impact of daylength in isolation on ecological communities has not been studied so far. Here, we tested for the direct and indirect effects of two different daylengths on the dynamics of experimental multitrophic insect communities. We compared the community dynamics under “southern” summer conditions of 14.5-hr daylight to “northern” summer conditions of 22-hr daylight. We show that food web dynamics indeed respond to daylength with one aphid species (Acyrthosiphon pisum) reaching much lower population sizes at the northern daylength regime compared to under southern conditions. In contrast, in the same communities, another aphid species (Megoura viciae) reached higher population densities under northern conditions. This effect at the aphid level was driven by an indirect effect of daylength causing a change in competitive interaction strengths, with the different aphid species being more competitive at different daylength regimes. Additionally, increasing daylength also increased growth rates in M. viciae making it more competitive under summer long days. As such, the shift in daylength affected aphid population sizes by both direct and indirect effects, propagating through species interactions. However, contrary to expectations, parasitoids were not affected by daylength. Our results demonstrate that range expansion of whole communities due to climate change can indeed change interaction strengths between species within ecological communities with consequences for community dynamics. This study provides the first evidence of daylength affecting community dynamics, which could not be predicted from studying single species separately.
Abstract.
Cox DTC, Shanahan DF, Hudson HL, Fuller RA, Gaston KJ (2018). The impact of urbanisation on nature dose and the implications for human health.
Landscape and Urban Planning,
179, 72-80.
Abstract:
The impact of urbanisation on nature dose and the implications for human health
The last 100 years have seen a huge change in the global structure of the human population, with the majority of people now living in urban rather than rural environments. An assumed consequence is that people will have fewer experiences of nature, and this could have important consequences given the myriad health benefits that they can gain from such experiences. Alternatively, as experiences of nature become rarer, people might be more likely actively to seek them out, mitigating the negative effects of urbanisation. In this study, we used data for 3000 survey respondents from across the UK, and a nature-dose framework, to determine whether (a) increasing urbanisation is associated with a decrease in the frequency, duration and intensity of nature dose; and (b) differences in nature exposure associated with urbanisation impact on four population health outcomes (depression, self-reported health, social cohesion and physical activity). We found negative exponential relationships between nature dose and the degree of urbanisation. The frequency and duration of dose decreased from rural to suburban environments, followed by little change with further increases in urbanisation. There were weak but positive associations between frequency and duration of dose across all four health domains, while different dimensions of dose showed more positive associations with specific health domains in towns and cities. We show that people in urban areas with a low nature dose tend to have worse health across multiple domains, but have the potential for the greatest gains from spending longer in nature, or living in green areas.
Abstract.
Sandino J, Gonzalez F, Mengersen K, Gaston KJ (2018). UAVs and machine learning revolutionising invasive grass and vegetation surveys in remote arid lands.
Sensors (Switzerland),
18(2).
Abstract:
UAVs and machine learning revolutionising invasive grass and vegetation surveys in remote arid lands
The monitoring of invasive grasses and vegetation in remote areas is challenging, costly, and on the ground sometimes dangerous. Satellite and manned aircraft surveys can assist but their use may be limited due to the ground sampling resolution or cloud cover. Straightforward and accurate surveillance methods are needed to quantify rates of grass invasion, offer appropriate vegetation tracking reports, and apply optimal control methods. This paper presents a pipeline process to detect and generate a pixel-wise segmentation of invasive grasses, using buffel grass (Cenchrus ciliaris) and spinifex (Triodia sp.) as examples. The process integrates unmanned aerial vehicles (UAVs) also commonly known as drones, high-resolution red, green, blue colour model (RGB) cameras, and a data processing approach based on machine learning algorithms. The methods are illustrated with data acquired in Cape Range National Park, Western Australia (WA), Australia, orthorectified in Agisoft Photoscan Pro, and processed in Python programming language, scikit-learn, and eXtreme Gradient Boosting (XGBoost) libraries. In total, 342,626 samples were extracted from the obtained data set and labelled into six classes. Segmentation results provided an individual detection rate of 97% for buffel grass and 96% for spinifex, with a global multiclass pixel-wise detection rate of 97%. Obtained results were robust against illumination changes, object rotation, occlusion, background cluttering, and floral density variation.
Abstract.
Parsons M, Bratanov D, Gaston KJ, Gonzalez F (2018). UAVs, hyperspectral remote sensing, and machine learning revolutionizing reef monitoring.
Sensors (Switzerland),
18(7).
Abstract:
UAVs, hyperspectral remote sensing, and machine learning revolutionizing reef monitoring
Recent advances in unmanned aerial system (UAS) sensed imagery, sensor quality/size, and geospatial image processing can enable UASs to rapidly and continually monitor coral reefs, to determine the type of coral and signs of coral bleaching. This paper describes an unmanned aerial vehicle (UAV) remote sensing methodology to increase the efficiency and accuracy of existing surveillance practices. The methodology uses a UAV integrated with advanced digital hyperspectral, ultra HD colour (RGB) sensors, and machine learning algorithms. This paper describes the combination of airborne RGB and hyperspectral imagery with in-water survey data of several types in-water survey of coral under diverse levels of bleaching. The paper also describes the technology used, the sensors, the UAS, the flight operations, the processing workflow of the datasets, the methods for combining multiple airborne and in-water datasets, and finally presents relevant results of material classification. The development of the methodology for the collection and analysis of airborne hyperspectral and RGB imagery would provide coral reef researchers, other scientists, and UAV practitioners with reliable data collection protocols and faster processing techniques to achieve remote sensing objectives.
Abstract.
Sutherland WJ, Barnard P, Broad S, Clout M, Connor B, Côté IM, Dicks LV, Doran H, Entwistle AC, Fleishman E, et al (2017). A 2017 horizon scan of emerging issues for global conservation and biological diversity.
Trends in Ecology and Evolution,
32(1), 31-40.
Abstract:
A 2017 horizon scan of emerging issues for global conservation and biological diversity
© 2016 the Authors We present the results of our eighth annual horizon scan of emerging issues likely to affect global biological diversity, the environment, and conservation efforts in the future. The potential effects of these novel issues might not yet be fully recognized or understood by the global conservation community, and the issues can be regarded as both opportunities and risks. A diverse international team with collective expertise in horizon scanning, science communication, and conservation research, practice, and policy reviewed 100 potential issues and identified 15 that qualified as emerging, with potential substantial global effects. These issues include new developments in energy storage and fuel production, sand extraction, potential solutions to combat coral bleaching and invasive marine species, and blockchain technology.
Abstract.
Chown SL, Brooks CM, Terauds A, Le Bohec C, van Klaveren-Impagliazzo C, Whittington JD, Butchart SHM, Coetzee BWT, Collen B, Convey P, et al (2017). Antarctica and the Strategic Plan for Biodiversity. PLoS Biology, 15(3).
Kyba CCM, Kuester T, Sanchez de Miguel A, Baugh K, Jechow A, Gaston KJ, Holker F, Bennie J, Elvidge CD, Guanter L, et al (2017). Artificially lit surface of Earth at night increasing in radiance and extent. Science Advances, 3
Cox DTC, Shanahan DF, Hudson HL, Fuller RA, Anderson K, Hancock S, Gaston KJ (2017). Doses of nearby nature simultaneously associated with multiple health benefits.
International Journal of Environmental Research and Public Health,
14(2).
Abstract:
Doses of nearby nature simultaneously associated with multiple health benefits
Exposure to nature provides a wide range of health benefits. A significant proportion of these are delivered close to home, because this offers an immediate and easily accessible opportunity for people to experience nature. However, there is limited information to guide recommendations on its management and appropriate use. We apply a nature dose-response framework to quantify the simultaneous association between exposure to nearby nature and multiple health benefits. We surveyed ca. 1000 respondents in Southern England, UK, to determine relationships between (a) nature dose type, that is the frequency and duration (time spent in private green space) and intensity (quantity of neighbourhood vegetation cover) of nature exposure and (b) health outcomes, including mental, physical and social health, physical behaviour and nature orientation. We then modelled dose-response relationships between dose type and self-reported depression. We demonstrate positive relationships between nature dose and mental and social health, increased physical activity and nature orientation. Dose-response analysis showed that lower levels of depression were associated with minimum thresholds of weekly nature dose. Nearby nature is associated with quantifiable health benefits, with potential for lowering the human and financial costs of ill health. Dose-response analysis has the potential to guide minimum and optimum recommendations on the management and use of nearby nature for preventative healthcare.
Abstract.
Cox DTC, Shanahan DF, Hudson HL, Plummer KE, Siriwardena GM, Fuller RA, Anderson K, Hancock S, Gaston KJ (2017). Doses of neighborhood nature: the benefits for mental health of living with nature.
BioScience,
67(2), 147-155.
Abstract:
Doses of neighborhood nature: the benefits for mental health of living with nature
Experiences of nature provide many mental-health benefits, particularly for people living in urban areas. The natural characteristics of city residents' neighborhoods are likely to be crucial determinants of the daily nature dose that they receive; however, which characteristics are important remains unclear. One possibility is that the greatest benefits are provided by characteristics that are most visible during the day and so most likely to be experienced by people. We demonstrate that of five neighborhood nature characteristics tested, vegetation cover and afternoon bird abundances were positively associated with a lower prevalence of depression, anxiety, and stress. Furthermore, dose-response modeling shows a threshold response at which the population prevalence of mental-health issues is significantly lower beyond minimum limits of neighborhood vegetation cover (depression more than 20% cover, anxiety more than 30% cover, stress more than 20% cover). Our findings demonstrate quantifiable associations of mental health with the characteristics of nearby nature that people actually experience.
Abstract.
Robinson BS, Inger R, Gaston KJ (2017). Drivers of risk perceptions about the invasive non-native plant Japanese knotweed in domestic gardens.
Biological Invasions,
19(10), 2927-2940.
Abstract:
Drivers of risk perceptions about the invasive non-native plant Japanese knotweed in domestic gardens
How people perceive risks posed by invasive non-native plants (INNP) can influence attitudes and consequently likely influence behavioural decisions. Although some drivers of risk perception for INNP have been identified, research has not determined those for INNP in domestic gardens. This is concerning as domestic gardens are where people most commonly encounter INNP, and where impacts can be particularly acute. Using a survey approach, this study determined the drivers of perceptions of risk of INNP in domestic gardens and which risks most concern people. Japanese knotweed Fallopia japonica, in Cornwall, UK, where it is a problematic INNP in domestic gardens, was used as a case study. Possible drivers of risk were chosen a priori based on variables previously found to be important for environmental risks. Participants perceived Japanese knotweed to be less frequent on domestic property in Cornwall if their occupation involved the housing market, if they had not had Japanese knotweed in their own garden, if they did not know of Japanese knotweed within 5 km of their home, or if they were educated to degree level. Participants who thought that the consequences of Japanese knotweed being present on domestic property could be more severe had occupations that involved the housing market, knew of Japanese knotweed within 5 km of their home, or were older. Although concern about the damage Japanese knotweed could do to the structure of a property was reported as the second highest motivation to control it by the majority of participants, the perception of threat from this risk was rated as relatively low. The results of this study have implications for policy, risk communication, and garden management decisions. For example, there is a need for policy that provides support and resources for people to manage INNP in their local area. To reduce the impact and spread of INNP we highlight the need for clear and accurate risk communication within discourse about this issue. The drivers identified in this study could be used to target awareness campaigns to limit the development of over- or under-inflated risk perceptions.
Abstract.
Casalegno S, Anderson K, Cox DTC, Hancock S, Gaston KJ (2017). Ecological connectivity in the three-dimensional urban green volume using waveform airborne lidar.
Scientific Reports,
7Abstract:
Ecological connectivity in the three-dimensional urban green volume using waveform airborne lidar
The movements of organisms and the resultant flows of ecosystem services are strongly shaped by landscape connectivity. Studies of urban ecosystems have relied on two-dimensional (2D) measures of greenspace structure to calculate connectivity. It is now possible to explore three-dimensional (3D) connectivity in urban vegetation using waveform lidar technology that measures the full 3D structure of the canopy. Making use of this technology, here we evaluate urban greenspace 3D connectivity, taking into account the full vertical stratification of the vegetation. Using three towns in southern England, UK, all with varying greenspace structures, we describe and compare the structural and functional connectivity using both traditional 2D greenspace models and waveform lidar-generated vegetation strata (namely, grass, shrubs and trees). Measures of connectivity derived from 3D greenspace are lower than those derived from 2D models, as the latter assumes that all vertical vegetation strata are connected, which is rarely true. Fragmented landscapes that have more complex 3D vegetation showed greater functional connectivity and we found highest 2D to 3D functional connectivity biases for short dispersal capacities of organisms (6 m to 16 m). These findings are particularly pertinent in urban systems where the distribution of greenspace is critical for delivery of ecosystem services.
Abstract.
De Freitas JR, Bennie J, Mantovani W, Gaston KJ (2017). Exposure of tropical ecosystems to artificial light at night: Brazil as a case study.
PLoS ONE,
12(2).
Abstract:
Exposure of tropical ecosystems to artificial light at night: Brazil as a case study
Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern.
Abstract.
Soga M, Gaston KJ, Yamaura Y (2017). Gardening is beneficial for health: a meta-analysis.
Preventive Medicine Reports,
5, 92-99.
Abstract:
Gardening is beneficial for health: a meta-analysis
There is increasing evidence that gardening provides substantial human health benefits. However, no formal statistical assessment has been conducted to test this assertion. Here, we present the results of a meta-analysis of research examining the effects of gardening, including horticultural therapy, on health. We performed a literature search to collect studies that compared health outcomes in control (before participating in gardening or non-gardeners) and treatment groups (after participating in gardening or gardeners) in January 2016. The mean difference in health outcomes between the two groups was calculated for each study, and then the weighted effect size determined both across all and sets of subgroup studies. Twenty-two case studies (published after 2001) were included in the meta-analysis, which comprised 76 comparisons between control and treatment groups. Most studies came from the United States, followed by Europe, Asia, and the Middle East. Studies reported a wide range of health outcomes, such as reductions in depression, anxiety, and body mass index, as well as increases in life satisfaction, quality of life, and sense of community. Meta-analytic estimates showed a significant positive effect of gardening on the health outcomes both for all and sets of subgroup studies, whilst effect sizes differed among eight subgroups. Although Egger's test indicated the presence of publication bias, significant positive effects of gardening remained after adjusting for this using trim and fill analysis. This study has provided robust evidence for the positive effects of gardening on health. A regular dose of gardening can improve public health.
Abstract.
Soga M, Cox DTC, Yamaura Y, Gaston KJ, Kurisu K, Hanaki K (2017). Health benefits of urban allotment gardening: Improved physical and psychological well-being and social integration.
International Journal of Environmental Research and Public Health,
14(1).
Abstract:
Health benefits of urban allotment gardening: Improved physical and psychological well-being and social integration
With an ever-increasing urban population, promoting public health and well-being in towns and cities is a major challenge. Previous research has suggested that participating in allotment gardening delivers a wide range of health benefits. However, evidence from quantitative analyses is still scarce. Here, we quantify the effects, if any, of participating in allotment gardening on physical, psychological and social health. A questionnaire survey of 332 people was performed in Tokyo, Japan. We compared five self-reported health outcomes between allotment gardeners and non-gardener controls: perceived general health, subjective health complaints, body mass index (BMI), mental health and social cohesion. Accounting for socio-demographic and lifestyle variables, regression models revealed that allotment gardeners, compared to non-gardeners, reported better perceived general health, subjective health complaints, mental health and social cohesion. BMI did not differ between gardeners and non-gardeners. Neither frequency nor duration of gardening significantly influenced reported health outcomes. Our results highlight that regular gardening on allotment sites is associated with improved physical, psychological and social health. With the recent escalation in the prevalence of chronic diseases, and associated healthcare costs, this study has a major implication for policy, as it suggests that urban allotments have great potential for preventative healthcare.
Abstract.
Lin BB, Gaston KJ, Fuller RA, Wu D, Bush R, Shanahan DF (2017). How green is your garden?: Urban form and socio-demographic factors influence yard vegetation, visitation, and ecosystem service benefits.
Landscape and Urban Planning,
157, 239-246.
Abstract:
How green is your garden?: Urban form and socio-demographic factors influence yard vegetation, visitation, and ecosystem service benefits
Private yards provide city residents with access to ecosystem services that can be realized through passive (vegetation availability) and active (time spent in yards: frequency and duration) means. However, urban densification is leading to smaller yards with less vegetation. Here, we examine how urban form and socio-demographic factors affect the potential ecosystem service benefits people can gain via passive (e.g. climate regulation) and active (e.g. recreation) pathways. Two measures of vegetation cover (0.15–2 m, >2 m) are used as a proxy for passive ecosystem service benefits, and two measures of yard use (use frequency, total time spent across a week) are used for active ecosystem service benefits. We use survey and GIS data to measure personal and physical predictors that could influence these variables for 520 residents of detached housing in Brisbane, Australia. We found house age and yard size were positively correlated with vegetation cover, and people with a greater nature relatedness and lower socio-economic disadvantage also had greater vegetation cover. Yard size was an important predictor of yard use, as was nature relatedness, householder age, and presence of children in the home. Vegetation cover showed no relationship, indicating that greater cover alone does not promote ecosystem service delivery through the active use pathway. Together our results show that people who have higher nature relatedness may receive greater benefits from their yards via both passive and active means as they have more vegetation available to them in their yards and they interact with this space more frequently and for longer time periods.
Abstract.
Gaston KJ, Davies TW, Nedelec SL, Holt LA (2017). Impacts of Artificial Light at Night on Biological Timings.
Annual Review of Ecology, Evolution, and Systematics,
48, 49-68.
Abstract:
Impacts of Artificial Light at Night on Biological Timings
The use of artificial lighting to illuminate the night has provided substantial benefits to humankind. It has also disrupted natural daily, seasonal, and lunar light cycles as experienced by a diversity of organisms, and hence it has also altered cues for the timings of many biological activities. Here we review the evidence for impacts of artificial nighttime lighting on these timings. Although the examples are scattered, concerning a wide variety of species and environments, the breadth of such impacts is compelling. Indeed, it seems reasonable to conclude that the vast majority of impacts of artificial nighttime lighting stem from effects on biological timings. This adds support to arguments that artificial nighttime lighting has a quite pervasive and marked impact on ecological systems, that the rapid expansion in the global extent of both direct illuminance and skyglow is thus of significant concern, and that a widespread implementation of mitigation measures is required.
Abstract.
Casalegno S, Anderson K, Hancock S, Gaston KJ (2017). Improving models of urban greenspace: from vegetation surface cover to volumetric survey, using waveform laser scanning.
Methods in Ecology and Evolution,
8(11), 1443-1452.
Abstract:
Improving models of urban greenspace: from vegetation surface cover to volumetric survey, using waveform laser scanning
Urban greenspace has a major impact on human health and quality of life, and thus the way in which such green infrastructure is constructed, managed and maintained is of critical importance. A range of studies have demonstrated the relationship between the areal coverage and distribution of vegetation and the provision of multiple urban ecosystem services. It is not known how sensitive findings are to the spatial resolution of the underlying data relative to the grain size of urban land cover heterogeneity. Moreover, little is known about the three-dimensional (3D) structure of urban vegetation and delivery of services, and addressing such questions is limited by the availability of data describing canopy structure from the tree tops to the ground. Waveform airborne laser scanning (lidar) offers a new way of capturing 3D data describing vegetation structure. We generated voxels (volumetric pixels) from waveform lidar (1·5 m resolution), differentiated vegetation layers using height as a determinant, and computed statistics on surface cover, volume and volume density per stratum. We then used a range of widely available remote sensing products with varying spatial resolution (1 to 100 m) to map the same greenspace, and compared results to those from the waveform lidar survey. We focused on data from three urban zones in the UK with distinct patterns of vegetation cover. We found −3%, +7·5% and +26·1% differences in green surface cover compared with, respectively, town planning maps (
Abstract.
Porcelli D, Gaston KJ, Butlin RK, Snook RR (2017). Local adaptation of reproductive performance during thermal stress.
Journal of Evolutionary Biology,
30(2), 422-429.
Abstract:
Local adaptation of reproductive performance during thermal stress
Considerable evidence exists for local adaptation of critical thermal limits in ectotherms following adult temperature stress, but fewer studies have tested for local adaptation of sublethal heat stress effects across life-history stages. In organisms with complex life cycles, such as holometabolous insects, heat stress during juvenile stages may severely impact gametogenesis, having downstream consequences on reproductive performance that may be mediated by local adaptation, although this is rarely studied. Here, we tested how exposure to either benign or heat stress temperature during juvenile and adult stages, either independently or combined, influences egg-to-adult viability, adult sperm motility and fertility in high- and low-latitude populations of Drosophila subobscura. We found both population- and temperature-specific effects on survival and sperm motility; juvenile heat stress decreased survival and subsequent sperm motility and each trait was lower in the northern population. We found an interaction between population and temperature on fertility following application of juvenile heat stress; although fertility was negatively impacted in both populations, the southern population was less affected. When the adult stage was also subject to heat stress, the southern population exhibited positive carry-over effects whereas the northern population's fertility remained low. Thus, the northern population is more susceptible to sublethal reproductive consequences following exposure to juvenile heat stress. This may be common in other organisms with complex life cycles and current models predicting population responses to climate change, which do not take into account the impact of juvenile heat stress on reproductive performance, may be too conservative.
Abstract.
Hancock S, Anderson K, Disney M, Gaston KJ (2017). Measurement of fine-spatial-resolution 3D vegetation structure with airborne waveform lidar: Calibration and validation with voxelised terrestrial lidar.
Remote Sensing of Environment,
188, 37-50.
Abstract:
Measurement of fine-spatial-resolution 3D vegetation structure with airborne waveform lidar: Calibration and validation with voxelised terrestrial lidar
Vegetation structure controls habitat availability, ecosystem services, weather, climate and microclimate, but current landscape scale vegetation maps have lacked details of understorey vegetation and within-canopy structure at resolutions finer than a few tens of metres. In this paper, a novel signal processing method is used to correctly measure 3D voxelised vegetation cover from full-waveform ALS data at 1.5 m horizontal and 50 cm vertical resolution, including understorey vegetation and within-canopy structure. A new method for calibrating and validating the instrument specific ALS processing using high resolution TLS data is also presented and used to calibrate and validate the ALS derived data products over a wide range of land cover types within a heterogeneous urban area, including woodland, gardens and streets. This showed the method to accurately retrieve voxelised canopy cover maps with less than 0.4% of voxels containing false negatives, 10% of voxels containing false positives and a canopy cover accuracy within voxels of 24%. The method was applied across 100 km2 and the resulting structure maps were compared to the more widely used discrete return ALS and Gaussian decomposed waveform ALS data products. These products were found to give little information on the within-canopy structure and so are only capable of deriving coarse resolution, plot-scale structure metrics. The detailed 3D canopy maps derived from the new method allow landscape scale ecosystem processes to be examined in more detail than has previously been possible, and the new method reveals details about the canopy understorey, creating opportunities for ecological investigations. The calibration method can be applied to any waveform ALS instrument and processing method. All code used in this paper is freely available online through bitbucket (https://bitbucket.org/StevenHancock/voxel_lidar).
Abstract.
Davies TW, Bennie J, Cruse D, Blumgart D, Inger R, Gaston KJ (2017). Multiple night-time light-emitting diode lighting strategies impact grassland invertebrate assemblages.
Global Change Biology,
23(7), 2641-2648.
Abstract:
Multiple night-time light-emitting diode lighting strategies impact grassland invertebrate assemblages
White light-emitting diodes (LEDs) are rapidly replacing conventional outdoor lighting technologies around the world. Despite rising concerns over their impact on the environment and human health, the flexibility of LEDs has been advocated as a means of mitigating the ecological impacts of globally widespread outdoor night-time lighting through spectral manipulation, dimming and switching lights off during periods of low demand. We conducted a three-year field experiment in which each of these lighting strategies was simulated in a previously artificial light naïve grassland ecosystem. White LEDs both increased the total abundance and changed the assemblage composition of adult spiders and beetles. Dimming LEDs by 50% or manipulating their spectra to reduce ecologically damaging wavelengths partially reduced the number of commoner species affected from seven to four. A combination of dimming by 50% and switching lights off between midnight and 04:00 am showed the most promise for reducing the ecological costs of LEDs, but the abundances of two otherwise common species were still affected. The environmental consequences of using alternative lighting technologies are increasingly well established. These results suggest that while management strategies using LEDs can be an effective means of reducing the number of taxa affected, averting the ecological impacts of night-time lighting may ultimately require avoiding its use altogether.
Abstract.
Dyer EE, Cassey P, Redding DW, Collen B, Franks V, Gaston KJ, Jones KE, Kark S, Orme CDL, Blackburn TM, et al (2017). The Global Distribution and Drivers of Alien Bird Species Richness.
PLoS Biology,
15(1).
Abstract:
The Global Distribution and Drivers of Alien Bird Species Richness
Alien species are a major component of human-induced environmental change. Variation in the numbers of alien species found in different areas is likely to depend on a combination of anthropogenic and environmental factors, with anthropogenic factors affecting the number of species introduced to new locations, and when, and environmental factors influencing how many species are able to persist there. However, global spatial and temporal variation in the drivers of alien introduction and species richness remain poorly understood. Here, we analyse an extensive new database of alien birds to explore what determines the global distribution of alien species richness for an entire taxonomic class. We demonstrate that the locations of origin and introduction of alien birds, and their identities, were initially driven largely by European (mainly British) colonialism. However, recent introductions are a wider phenomenon, involving more species and countries, and driven in part by increasing economic activity. We find that, globally, alien bird species richness is currently highest at midlatitudes and is strongly determined by anthropogenic effects, most notably the number of species introduced (i.e. “colonisation pressure”). Nevertheless, environmental drivers are also important, with native and alien species richness being strongly and consistently positively associated. Our results demonstrate that colonisation pressure is key to understanding alien species richness, show that areas of high native species richness are not resistant to colonisation by alien species at the global scale, and emphasise the likely ongoing threats to global environments from introductions of species.
Abstract.
Cox DTC, Hudson HL, Shanahan DF, Fuller RA, Gaston KJ (2017). The rarity of direct experiences of nature in an urban population.
Landscape and Urban Planning,
160, 79-84.
Abstract:
The rarity of direct experiences of nature in an urban population
As people live more urbanised lifestyles there is potential to lose daily contact with nature, diminishing access to the wide range of associated health benefits of interacting with nature. Experiences of nature vary widely across populations, but this variation is poorly understood. We surveyed 1023 residents of an urban population in the UK to measure four distinctly different nature interactions: indirect (viewing nature through a window at work and at home), incidental (spending time outside at work), intentional (time spent in private gardens) and intentional (time spent in public parks). Scaled-up to the whole study population, accumulation curves of the total number of hours per week that people were exposed to each type of nature interaction showed that 75% of nature interactions were experienced by half the population. Moreover, 75% of the interactions of a type where people were actually present in nature were experienced by just 32% of the population. The average hours each individual experienced nature per week varied across interactions: indirect (46.0 ± 27.3 SD), incidental (6.4 ± 12.7 SD), intentional-gardens (2.5 ± 2.9 SD) and intentional-parks (2.3 ± 2.7 SD). Experiencing nature regularly appears to be the exception rather than the norm, with a person's connection to nature being positively associated with incidental and intentional experiences. This novel study provides baseline information regarding how an urban population experiences different types of nature. Deconstructing nature experience will pave the way for developing recommendations for targeted health outcomes.
Abstract.
Shanahan DF, Cox DTC, Fuller RA, Hancock S, Lin BB, Anderson K, Bush R, Gaston KJ (2017). Variation in experiences of nature across gradients of tree cover in compact and sprawling cities.
Landscape and Urban Planning,
157, 231-238.
Abstract:
Variation in experiences of nature across gradients of tree cover in compact and sprawling cities
Urban environments are expanding globally, and by 2050 nearly 70% of the world's population will live in towns and cities, where opportunities to experience nature are more limited than in rural areas. This transition could have important implications for health and wellbeing given the diversity of benefits that nature delivers. Despite these issues, there is a lack of information on whether or how the experience of nature changes as green space becomes less available. We explore this question for residents of two case study cities of varying urban designs, sprawling (Brisbane, Australia) and compact (three English towns, U.K). Second, we examine how people's feelings of connection to nature (measured using the Nature Relatedness scale) vary across this same gradient of nature availability. Despite climatic and cultural differences we found substantial similarities between the two locations. Lower levels of neighbourhood tree cover were associated with a reduced frequency of visits to private and public green spaces, and a similar pattern was found for the duration of time spent in private and public green spaces for Brisbane. Residents of both urban areas showed similar levels of nature relatedness, and there was a weak but positive association between tree cover and Nature Relatedness. These results suggest that regardless of the style of urban design, maintaining the availability of nature close to home is a critical step to protect people's experiences of nature and their desire to seek out those experiences.
Abstract.
Robinson BS, Inger R, Crowley SL, Gaston KJ (2017). Weeds on the web: conflicting management advice about an invasive non-native plant.
Journal of Applied Ecology,
54(1), 178-187.
Abstract:
Weeds on the web: conflicting management advice about an invasive non-native plant
Invasive non-native plants (INNPs) can have serious and widespread negative ecological and socio-economic impacts. It is therefore important they are managed appropriately. Within domestic gardens management decisions, which will tend to be made by individual members of the public, are likely to vary depending on (a) understanding of problems caused by INNP, and (b) knowledge of best practice. Using content analysis, an approach seldom employed in an ecological context, this study analysed variation in internet-based information sources regarding INNP to determine how this collective discourse might influence risk perceptions and management decisions for domestic garden owners/managers. We used Japanese knotweed Fallopia japonica in the UK, as a case study, as it is one of the most ecologically and economically damaging INNP in the region. Our analysis categorized the types of author disseminating information about Japanese knotweed, the relative frequency of documents between author categories, and variation in content and style between and within author categories. We identified five author categories: environmental NGOs, control companies, government, media and the property market. There was extensive variation in document structure, topics discussed, references and links to other sources, and language style; sometimes this variation was between author categories and sometimes within author categories. The most significant variation in topics discussed between author categories was indirect socio-economic problems, with control companies discussing these most. The number of pieces of legislation referenced and the proportion of militaristic words used were also highly significantly different between author categories. Some documents used neutral terminology and were more circumspect, whilst others were more forceful in expressing opinions and sensational. The author category returning the highest number of documents was the subcategory local government, the shortest of which contained neither links to other information nor referenced any organizations. Further analysis of local government documents revealed conflicting advice regarding the disposal of Japanese knotweed waste material; confusion about this topic could result in decisions being made that spread Japanese knotweed further and are potentially unlawful. The potential implications of our findings for the management of INNP in domestic gardens and societal perceptions of risks posed by INNP are discussed. Synthesis and applications. To help prevent inappropriate management of invasive non-native plants (INNPs), for example Japanese knotweed Fallopia japonica in domestic gardens, we recommend that local and national authorities collaborate and work towards disseminating more consistent messages about (a) the potential socio-economic and ecological problems caused by INNP, whilst avoiding hyperbole, and (b) the most appropriate management techniques.
Abstract.
Soga M, Gaston KJ, Yamaura Y, Kurisu K, Hanaki K (2016). Both direct and vicarious experiences of nature affect children’s willingness to conserve biodiversity.
International Journal of Environmental Research and Public Health,
13(6).
Abstract:
Both direct and vicarious experiences of nature affect children’s willingness to conserve biodiversity
Children are becoming less likely to have direct contact with nature. This ongoing loss of human interactions with nature, the extinction of experience, is viewed as one of the most fundamental obstacles to addressing global environmental challenges. However, the consequences for biodiversity conservation have been examined very little. Here, we conducted a questionnaire survey of elementary schoolchildren and investigated effects of the frequency of direct (participating in nature-based activities) and vicarious experiences of nature (reading books or watching TV programs about nature and talking about nature with parents or friends) on their affective attitudes (individuals’ emotional feelings) toward and willingness to conserve biodiversity. A total of 397 children participated in the surveys in Tokyo. Children’s affective attitudes and willingness to conserve biodiversity were positively associated with the frequency of both direct and vicarious experiences of nature. Path analysis showed that effects of direct and vicarious experiences on children’s willingness to conserve biodiversity were mediated by their affective attitudes. This study demonstrates that children who frequently experience nature are likely to develop greater emotional affinity to and support for protecting biodiversity. We suggest that children should be encouraged to experience nature and be provided with various types of these experiences.
Abstract.
Collen B, Dulvy NK, Gaston KJ, Gärdenfors U, Keith DA, Punt AE, Regan HM, Böhm M, Hedges S, Seddon M, et al (2016). Clarifying misconceptions of extinction risk assessment with the IUCN Red List.
Biol Lett,
12(4).
Abstract:
Clarifying misconceptions of extinction risk assessment with the IUCN Red List.
The identification of species at risk of extinction is a central goal of conservation. As the use of data compiled for IUCN Red List assessments expands, a number of misconceptions regarding the purpose, application and use of the IUCN Red List categories and criteria have arisen. We outline five such classes of misconception; the most consequential drive proposals for adapted versions of the criteria, rendering assessments among species incomparable. A key challenge for the future will be to recognize the point where understanding has developed so markedly that it is time for the next generation of the Red List criteria. We do not believe we are there yet but, recognizing the need for scrutiny and continued development of Red Listing, conclude by suggesting areas where additional research could be valuable in improving the understanding of extinction risk among species.
Abstract.
Author URL.
Bennie J, Davies TW, Cruse D, Gaston KJ (2016). Ecological effects of artificial light at night on wild plants. Journal of Ecology, 104(3), 611-620.
Inger R, Cox DTC, Per E, Norton BA, Gaston KJ (2016). Ecological role of vertebrate scavengers in urban ecosystems in the UK.
Ecology and Evolution,
6(19), 7015-7023.
Abstract:
Ecological role of vertebrate scavengers in urban ecosystems in the UK
Recent research has demonstrated how scavenging, the act of consuming dead animals, plays a key role in ecosystem structure, functioning, and stability. A growing number of studies suggest that vertebrate scavengers also provide key ecosystem services, the benefits humans gain from the natural world, particularly in the removal of carcasses from the environment. An increasing proportion of the human population is now residing in cities and towns, many of which, despite being highly altered environments, contain significant wildlife populations, and so animal carcasses. Indeed, non-predation fatalities may be higher within urban than natural environments. Despite this, the fate of carcasses in urban environments and the role vertebrate scavengers play in their removal have not been determined. In this study, we quantify the role of vertebrate scavengers in urban environments in three towns in the UK. Using experimentally deployed rat carcasses and rapid fire motion-triggered cameras, we determined which species were scavenging and how removal of carcass biomass was partitioned between them. of the 63 experimental carcasses deployed, vertebrate scavenger activity was detected at 67%. There was a significantly greater depletion in carcass biomass in the presence (mean loss of 194�g) than absence (mean loss of 14�g) of scavengers. Scavenger activity was restricted to three species, Carrion crows Corvus corone, Eurasian magpies Pica pica, and European red foxes Vulpes vulpes. From behavioral analysis, we estimated that a maximum of 73% of the carcass biomass was removed by vertebrate scavengers. Despite having low species richness, the urban scavenger community in our urban study system removed a similar proportion of carcasses to those reported in more pristine environments. Vertebrate scavengers are providing a key urban ecosystem service in terms of carcass removal. This service is, however, often overlooked, and the species that provide it are among some of the most disliked and persecuted.
Abstract.
Wu XG, Hu D, Ma SL, Zhang X, Guo Z, Gaston KJ (2016). Elevated soil CO<inf>2</inf> efflux at the boundaries between impervious surfaces and urban greenspaces.
Atmospheric Environment,
141, 375-378.
Abstract:
Elevated soil CO2 efflux at the boundaries between impervious surfaces and urban greenspaces
Impervious surfaces and greenspaces have significant impacts on ecological processes and ecosystem services in urban areas. However, there have been no systematic studies of how the interaction between the two forms of land cover, and especially their edge effects, influence ecosystem properties. This has made it difficult to evaluate the effectiveness of urban greenspace design in meeting environmental goals. In this study, we investigated edge effects on soil carbon dioxide (CO2) fluxes in Beijing and found that soil CO2 flux rates were averagely 73% higher 10 cm inwards from the edge of greenspaces. Distance, soil temperature, moisture, and their interaction significantly influenced soil CO2 flux rates. The magnitude and distance of edge effects differed among impervious structure types. Current greening policy and design should be adjusted to avoid the carbon sequestration service of greenspaces being limited by their fragmentation.
Abstract.
Soga M, Gaston KJ (2016). Extinction of experience: the loss of human-nature interactions.
Frontiers in Ecology and the Environment,
14(2), 94-101.
Abstract:
Extinction of experience: the loss of human-nature interactions
Increasingly, people are becoming less likely to have direct contact with nature (natural environments and their associated wildlife) in their everyday lives. Over 20 years ago, Robert M Pyle termed this ongoing alienation the "extinction of experience", but the phenomenon has continued to receive surprisingly limited attention. Here, we present current understanding of the extinction of experience, with particular emphasis on its causes and consequences, and suggest future research directions. Our review illustrates that the loss of interaction with nature not only diminishes a wide range of benefits relating to health and well-being, but also discourages positive emotions, attitudes, and behavior with regard to the environment, implying a cycle of disaffection toward nature. Such serious implications highlight the importance of reconnecting people with nature, as well as focusing research and public policy on addressing and improving awareness of the extinction of experience.
Abstract.
Porcelli D, Westram AM, Pascual M, Gaston KJ, Butlin RK, Snook RR (2016). Gene expression clines reveal local adaptation and associated trade-offs at a continental scale.
Scientific Reports,
6Abstract:
Gene expression clines reveal local adaptation and associated trade-offs at a continental scale
Local adaptation, where fitness in one environment comes at a cost in another, should lead to spatial variation in trade-offs between life history traits and may be critical for population persistence. Recent studies have sought genomic signals of local adaptation, but often have been limited to laboratory populations representing two environmentally different locations of a species' distribution. We measured gene expression, as a proxy for fitness, in males of Drosophila subobscura, occupying a 20° latitudinal and 11 °C thermal range. Uniquely, we sampled six populations and studied both common garden and semi-natural responses to identify signals of local adaptation. We found contrasting patterns of investment: transcripts with expression positively correlated to latitude were enriched for metabolic processes, expressed across all tissues whereas negatively correlated transcripts were enriched for reproductive processes, expressed primarily in testes. When using only the end populations, to compare our results to previous studies, we found that locally adaptive patterns were obscured. While phenotypic trade-offs between metabolic and reproductive functions across widespread species are well-known, our results identify underlying genetic and tissue responses at a continental scale that may be responsible for this. This may contribute to understanding population persistence under environmental change.
Abstract.
Shanahan DF, Bush R, Gaston KJ, Lin BB, Dean J, Barber E, Fuller RA (2016). Health Benefits from Nature Experiences Depend on Dose.
Scientific Reports,
6Abstract:
Health Benefits from Nature Experiences Depend on Dose
Nature within cities will have a central role in helping address key global public health challenges associated with urbanization. However, there is almost no guidance on how much or how frequently people need to engage with nature, and what types or characteristics of nature need to be incorporated in cities for the best health outcomes. Here we use a nature dose framework to examine the associations between the duration, frequency and intensity of exposure to nature and health in an urban population. We show that people who made long visits to green spaces had lower rates of depression and high blood pressure, and those who visited more frequently had greater social cohesion. Higher levels of physical activity were linked to both duration and frequency of green space visits. A dose-response analysis for depression and high blood pressure suggest that visits to outdoor green spaces of 30 minutes or more during the course of a week could reduce the population prevalence of these illnesses by up to 7% and 9% respectively. Given that the societal costs of depression alone in Australia are estimated at AUD$12.6 billion per annum, savings to public health budgets across all health outcomes could be immense.
Abstract.
Anderson K, Hancock S, Disney M, Gaston KJ (2016). Is waveform worth it? a comparison of LiDAR approaches for vegetation and landscape characterization.
Remote Sensing in Ecology and Conservation,
2(1), 5-15.
Abstract:
Is waveform worth it? a comparison of LiDAR approaches for vegetation and landscape characterization
Light Detection and Ranging (LiDAR) systems are frequently used in ecological studies to measure vegetation canopy structure. Waveform LiDAR systems offer new capabilities for vegetation modelling by measuring the time-varying signal of the laser pulse as it illuminates different elements of the canopy, providing an opportunity to describe the 3D structure of vegetation canopies more fully. This article provides a comparison between waveform airborne laser scanning (ALS) data and discrete return ALS data, using terrestrial laser scanning (TLS) data as an independent validation. With reference to two urban landscape typologies, we demonstrate that discrete return ALS data provided more biased and less consistent measurements of woodland canopy height (in a 100% tree covered plot, height underestimation bias = 0.82 m; sd = 1.78 m) than waveform ALS data (height overestimation bias = −0.65 m; sd = 1.45 m). The same biases were found in suburban data (in a plot consisting of 100% hard targets e.g. roads and pavements), but discrete return ALS were more consistent here than waveform data (sd = 0.57 m compared to waveform sd = 0.76 m). Discrete return ALS data performed poorly in describing the canopy understorey, compared to waveform data. Our results also highlighted errors in discrete return ALS intensity, which were not present with waveform data. Waveform ALS data therefore offer an improved method for measuring the three-dimensional structure of vegetation systems, but carry a higher data processing cost. New toolkits for analysing waveform data will expedite future analysis and allow ecologists to exploit the information content of waveform LiDAR.
Abstract.
Inger R, Per E, Cox DTC, Gaston KJ (2016). Key role in ecosystem functioning of scavengers reliant on a single common species.
Scientific Reports,
6Abstract:
Key role in ecosystem functioning of scavengers reliant on a single common species
The importance of species richness in maintaining ecosystem function in the field remains unclear. Recent studies however have suggested that in some systems functionality is maintained by a few abundant species. Here we determine this relationship by quantifying the species responsible for a key ecosystem role, carcass removal by scavengers. We find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species, the Carrion crow, despite the presence of a number of other scavenging species. Furthermore, we find no relationship between abundance of crows and carcass removal. However, the overall activity of crows predicts carcass biomass removal rate in an asymptotic manner, suggesting that a relatively low level of abundance and scavenging activity is required to maintain this component of ecosystem function.
Abstract.
Allinson D, Irvine KN, Edmondson JL, Tiwary A, Hill G, Morris J, Bell M, Davies ZG, Firth SK, Fisher J, et al (2016). Measurement and analysis of household carbon: the case of a UK city.
Applied Energy,
164, 871-881.
Abstract:
Measurement and analysis of household carbon: the case of a UK city
There is currently a lack of data recording the carbon and emissions inventory at household level. This paper presents a multi-disciplinary, bottom-up approach for estimation and analysis of the carbon emissions, and the organic carbon (OC) stored in gardens, using a sample of 575 households across a UK city. The annual emission of carbon dioxide emissions from energy used in the homes was measured, personal transport emissions were assessed through a household survey and OC stores estimated from soil sampling and vegetation surveys. The results showed that overall carbon patterns were skewed with highest emitting third of the households being responsible for more than 50% of the emissions and around 50% of garden OC storage. There was diversity in the relative contribution that gas, electricity and personal transport made to each household's total and different patterns were observed for high, medium and low emitting households. Targeting households with high carbon emissions from one source would not reliably identify them as high emitters overall. While carbon emissions could not be offset by growing trees in gardens, there were considerable amounts of stored OC in gardens which ought to be protected. Exploratory analysis of the multiple drivers of emissions was conducted using a combination of primary and secondary data. These findings will be relevant in devising effective policy instruments for combatting city scale green-house gas emissions from domestic end-use energy demand.
Abstract.
Cox DTC, Inger R, Hancock S, Anderson K, Gaston KJ (2016). Movement of feeder-using songbirds: the influence of urban features.
Scientific Reports,
6Abstract:
Movement of feeder-using songbirds: the influence of urban features
Private gardens provide vital opportunities for people to interact with nature. The most popular form of interaction is through garden bird feeding. Understanding how landscape features and seasons determine patterns of movement of feeder-using songbirds is key to maximising the well-being benefits they provide. To determine these patterns we established three networks of automated data loggers along a gradient of greenspace fragmentation. Over a 12-month period we tracked 452 tagged blue tits Cyantistes caeruleus and great tits Parus major moving between feeder pairs 9,848 times, to address two questions: (i) Do urban features within different forms, and season, influence structural (presence-absence of connections between feeders by birds) and functional (frequency of these connections) connectivity? (ii) Are there general patterns of structural and functional connectivity across forms? Vegetation cover increased connectivity in all three networks, whereas the presence of road gaps negatively affected functional but not structural connectivity. Across networks structural connectivity was lowest in the summer when birds maintain breeding territories, however patterns of functional connectivity appeared to vary with habitat fragmentation. Using empirical data this study shows how key urban features and season influence movement of feeder-using songbirds, and we provide evidence that this is related to greenspace fragmentation.
Abstract.
Edmondson JL, Stott I, Davies ZG, Gaston KJ, Leake JR (2016). Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.
Scientific Reports,
6Abstract:
Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs
Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.
Abstract.
Davies TW, Duffy JP, Bennie J, Gaston KJ (2016). Stemming the Tide of Light Pollution Encroaching into Marine Protected Areas.
Conservation Letters,
9(3), 164-171.
Abstract:
Stemming the Tide of Light Pollution Encroaching into Marine Protected Areas
Many marine ecosystems are shaped by regimes of natural light guiding the behavior of their constituent species. As evidenced from terrestrial systems, the global introduction of nighttime lighting is likely influencing these behaviors, restructuring marine ecosystems, and compromising the services they provide. Yet the extent to which marine habitats are exposed to artificial light at night is unknown. We quantified nighttime artificial light across the world's network of marine protected areas (MPAs). Artificial light is widespread and increasing in a large percentage of MPAs. While increases are more common among MPAs associated with human activity, artificial light is encroaching into a large proportion of even those marine habitats protected with the strongest legislative designations. Given the current lack of statutory tools, we propose that allocating “Marine Dark Sky Park” status to MPAs will help incentivize responsible authorities to hold back the advance of artificial light.
Abstract.
Shanahan DF, Franco L, Lin BB, Gaston KJ, Fuller RA (2016). The Benefits of Natural Environments for Physical Activity.
Sports Med,
46(7), 989-995.
Abstract:
The Benefits of Natural Environments for Physical Activity.
Urbanisation has a profound effect on both people and the environment, as levels of physical activity decline and many natural ecosystems become lost or degraded. Here we draw on emerging research to examine the role of green spaces in providing a venue for outdoor physical activity, and in enhancing the benefit of a given amount of physical activity for urban residents. We identify critical knowledge gaps, including (1) whether (and for whom) levels of physical activity increase as new green spaces are introduced or old spaces reinvigorated; (2) which characteristics of nature promote physical activity; (3) the extent to which barriers to outdoor physical activity are environmental or social; and (4) whether the benefits of physical activity and experiences of nature accrue separately or synergistically. A clear understanding of these issues will help guide effective investment in green space provision, ecological enhancement and green exercise promotion.
Abstract.
Author URL.
Dallimer M, Tang Z, Gaston KJ, Davies ZG (2016). The extent of shifts in vegetation phenology between rural and urban areas within a human-dominated region.
Ecology and Evolution,
6(7), 1942-1953.
Abstract:
The extent of shifts in vegetation phenology between rural and urban areas within a human-dominated region
Urbanization is one of the major environmental challenges facing the world today. One of its particularly pressing effects is alterations to local and regional climate through, for example, the Urban Heat Island. Such changes in conditions are likely to have an impact on the phenology of urban vegetation, which will have knock-on implications for the role that urban green infrastructure can play in delivering multiple ecosystem services. Here, in a human-dominated region, we undertake an explicit comparison of vegetation phenology between urban and rural zones. Using satellite-derived MODIS-EVI data from the first decade of the 20th century, we extract metrics of vegetation phenology (date of start of growing season, date of end of growing season, and length of season) for Britain's 15 largest cities and their rural surrounds. On average, urban areas experienced a growing season 8.8 days longer than surrounding rural zones. As would be expected, there was a significant decline in growing season length with latitude (by 3.4 and 2.4 days/degree latitude in rural and urban areas respectively). Although there is considerable variability in how phenology in urban and rural areas differs across our study cities, we found no evidence that built urban form influences the start, end, or length of the growing season. However, the difference in the length of the growing season between rural and urban areas was significantly negatively associated with the mean disposable household income for a city. Vegetation in urban areas deliver many ecosystem services such as temperature mitigation, pollution removal, carbon uptake and storage, the provision of amenity value for humans and habitat for biodiversity. Given the rapid pace of urbanization and ongoing climate change, understanding how vegetation phenology will alter in the future is important if we wish to be able to manage urban greenspaces effectively.
Abstract.
Gonzalez LF, Montes GA, Puig E, Johnson S, Mengersen K, Gaston KJ (2016). Unmanned aerial vehicles (UAVs) and artificial intelligence revolutionizing wildlife monitoring and conservation.
Sensors (Switzerland),
16(1).
Abstract:
Unmanned aerial vehicles (UAVs) and artificial intelligence revolutionizing wildlife monitoring and conservation
Surveying threatened and invasive species to obtain accurate population estimates is an important but challenging task that requires a considerable investment in time and resources. Estimates using existing ground-based monitoring techniques, such as camera traps and surveys performed on foot, are known to be resource intensive, potentially inaccurate and imprecise, and difficult to validate. Recent developments in unmanned aerial vehicles (UAV), artificial intelligence and miniaturized thermal imaging systems represent a new opportunity for wildlife experts to inexpensively survey relatively large areas. The system presented in this paper includes thermal image acquisition as well as a video processing pipeline to perform object detection, classification and tracking of wildlife in forest or open areas. The system is tested on thermal video data from ground based and test flight footage, and is found to be able to detect all the target wildlife located in the surveyed area. The system is flexible in that the user can readily define the types of objects to classify and the object characteristics that should be considered during classification.
Abstract.
Cox DTC, Gaston KJ (2016). Urban bird feeding: Connecting people with nature.
PLoS ONE,
11(7).
Abstract:
Urban bird feeding: Connecting people with nature
At a time of unprecedented biodiversity loss, researchers are increasingly recognizing the broad range of benefits provided to humankind by nature. However, as people live more urbanized lifestyles there is a progressive disengagement with the natural world that diminishes these benefits and discourages positive environmental behaviour. The provision of food for garden birds is an increasing global phenomenon, and provides a readily accessible way for people to counter this trend. Yet despite its popularity, quite why people feed birds remains poorly understood. We explore three loosely defined motivations behind bird feeding: that it provides psychological benefits, is due to a concern about bird welfare, and/or is due to a more general orientation towards nature. We quantitatively surveyed households from urban towns in southern England to explore attitudes and actions towards garden bird feeding. Each household scored three Likert statements relating to each of the three motivations. We found that people who fed birds regularly felt more relaxed and connected to nature when they watched garden birds, and perceived that bird feeding is beneficial for bird welfare while investing time in minimising associated risks. Finally, feeding birds may be an expression of a wider orientation towards nature. Overall, we found that the feelings of being relaxed and connected to nature were the strongest drivers. As urban expansion continues both to threaten species conservation and to change peoples' relationship with the natural world, feeding birds may provide an important tool for engaging people with nature to the benefit of both people and conservation.
Abstract.
Soga M, Gaston KJ, Koyanagi TF, Kurisu K, Hanaki K (2016). Urban residents' perceptions of neighbourhood nature: Does the extinction of experience matter?.
Biological Conservation,
203, 143-150.
Abstract:
Urban residents' perceptions of neighbourhood nature: Does the extinction of experience matter?
Today's children have less direct contact with nature than ever before, resulting in an “extinction of experience”. Research has suggested that such loss of daily interactions decreases people's appreciation of the natural world, but this remains quantitatively unexplored. We conducted a questionnaire survey of undergraduate university students in Tokyo, Japan, and determined the effects of frequency of contact with nature on emotional connectedness to nature and perceptions of neighbourhood nature. A total of 255 students participated in the surveys. Students' perceptions of neighbourhood nature were measured by to what extent they valued cultural ecosystem services derived from neighbourhood natural environments, birds and butterflies. Results showed that students valued neighbourhood natural environments, birds and butterflies for many different reasons, such as relaxation, beauty of natural scenes, an indicator of seasonality, and opportunities for education. Linear mixed models revealed that both current and childhood frequencies of contact with nature were positively related not only to students' emotional connectedness to nature but also their perceptions of neighbourhood nature. Students' emotional connection to nature and perceptions of neighbourhood nature were positively associated with each other. Our results suggest that, given the rapid decrease in children's daily contact with nature, public appreciation of the value of the natural world is likely gradually also to decrease. This can be a major obstacle to reversing global environmental challenges. People should therefore be encouraged to experience neighbourhood natural environments and biodiversity, and city planners and policy makers will play a vital role in connecting people with nature.
Abstract.
Sanders D, Kehoe R, Tiley K, Bennie J, Cruse D, Davies TW, Frank van Veen FJ, Gaston KJ (2015). Artificial nighttime light changes aphid-parasitoid population dynamics.
Sci Rep,
5Abstract:
Artificial nighttime light changes aphid-parasitoid population dynamics.
Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species and their specialist parasitoids. The light treatment reduced the abundance of two aphid species by 20% over five generations, most likely as a consequence of bottom-up effects, with reductions in bean plant biomass being observed. For the aphid Megoura viciae this effect was reversed under autumn conditions with the light treatment promoting continuous reproduction through asexuals. All three parasitoid species were negatively affected by the light treatment, through reduced host numbers and we discuss induced possible behavioural changes. These results suggest that, in addition to direct impacts on species behaviour, the impacts of ALAN can cascade through food webs with potentially far reaching effects on the wider ecosystem.
Abstract.
Author URL.
Gaston KJ, Gaston S, Bennie J, Hopkins J (2015). Benefits and costs of artificial nighttime lighting of the environment.
Environmental Reviews,
23(1), 14-23.
Abstract:
Benefits and costs of artificial nighttime lighting of the environment
Artificial lighting has transformed the outdoor nighttime environment over large areas, modifying natural cycles of light in terms of timing, wavelength, and distribution. This has had widespread benefits and costs to humankind, impacting on health and wellbeing, vehicle accidents, crime, energy consumption and carbon emissions, aesthetics, and wildlife and ecosystems. Here, we review these effects, particularly in the context of ongoing developments in the extent of artificial lighting and in the prevalent technologies being employed. The key issue that emerges is how best to maximize the benefits of artificial nighttime lighting whilst limiting the costs. To do so, three main strategies are required. First, important knowledge gaps need to be filled. Second, there is an urgent need to connect the research being conducted in different disciplines, which to date has been very disjointed. Third, it is imperative that much firmer and well-developed links are made between research, policy, and practice.
Abstract.
Edmondson JL, Stott I, Potter J, Lopez-Capel E, Manning DAC, Gaston KJ, Leake JR (2015). Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.
Environ Sci Technol,
49(14), 8339-8346.
Abstract:
Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.
Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas.
Abstract.
Author URL.
Bennie J, Davies TW, Cruse D, Inger R, Gaston KJ (2015). Cascading effects of artificial light at night: resource-mediated control of herbivores in a grassland ecosystem.
Philos Trans R Soc Lond B Biol Sci,
370(1667).
Abstract:
Cascading effects of artificial light at night: resource-mediated control of herbivores in a grassland ecosystem.
Artificial light at night has a wide range of biological effects on both plants and animals. Here, we review mechanisms by which artificial light at night may restructure ecological communities by modifying the interactions between species. Such mechanisms may be top-down (predator, parasite or grazer controlled), bottom-up (resource-controlled) or involve non-trophic processes, such as pollination, seed dispersal or competition. We present results from an experiment investigating both top-down and bottom-up effects of artificial light at night on the population density of pea aphids Acyrthosiphon pisum in a diverse artificial grassland community in the presence and absence of predators and under low-level light of different spectral composition. We found no evidence for top-down control of A. pisum in this system, but did find evidence for bottom-up effects mediated through the impact of light on flower head density in a leguminous food plant. These results suggest that physiological effects of light on a plant species within a diverse plant community can have detectable demographic effects on a specialist herbivore.
Abstract.
Author URL.
Inger R, Gregory R, Duffy JP, Stott I, Voříšek P, Gaston KJ (2015). Common European birds are declining rapidly while less abundant species' numbers are rising.
Ecol Lett,
18(1), 28-36.
Abstract:
Common European birds are declining rapidly while less abundant species' numbers are rising.
Biodiversity is undergoing unprecedented global decline. Efforts to slow this rate have focused foremost on rarer species, which are at most risk of extinction. Less interest has been paid to more common species, despite their greater importance in terms of ecosystem function and service provision. How rates of decline are partitioned between common and less abundant species remains unclear. Using a 30-year data set of 144 bird species, we examined Europe-wide trends in avian abundance and biomass. Overall, avian abundance and biomass are both declining with most of this decline being attributed to more common species, while less abundant species showed an overall increase in both abundance and biomass. If overall avian declines are mainly due to reductions in a small number of common species, conservation efforts targeted at rarer species must be better matched with efforts to increase overall bird numbers, if ecological impacts of birds are to be maintained.
Abstract.
Author URL.
Kyba CCM, Tong KP, Bennie J, Birriel I, Birriel JJ, Cool A, Danielsen A, Davies TW, den Outer PN, Edwards W, et al (2015). Corrigendum: Worldwide variations in artificial skyglow.
Sci Rep,
5 Author URL.
Bonnington C, Gaston KJ, Evans KL (2015). Ecological traps and behavioural adjustments of urban songbirds to fine-scale spatial variation in predator activity.
Animal ConservationAbstract:
Ecological traps and behavioural adjustments of urban songbirds to fine-scale spatial variation in predator activity
© 2015 the Zoological Society of London. The influence of predators on bird populations is controversial and poorly understood, especially in urban areas where predator densities can be particularly high. We assessed if fine-scale spatial variation in predator activity and proximity have direct and indirect effects on urban songbird distributions and breeding success, by testing the hypotheses that (1) songbirds that are sensitive to nest predation select territories with reduced activity of nest predators; (2) blackbird Turdus merula, a species that experiences high nest predation rates, lays smaller clutches in territories located in areas with higher numbers of nest predators as predicted by Skutch's hypothesis; (3) songbirds that are sensitive to nest predation have higher nest predation rates in areas with greater predator activity. We tested these hypotheses using two sites in urban Sheffield, UK, and focus on nest predatory corvids and grey squirrels Sciurus carolinensis. We found no evidence that songbirds that are most sensitive to nest predation adjust their territory location in response to fine-scale spatial variation in predator distributions. It thus seems unlikely that urban predators are indirectly regulating urban bird population size by restricting habitat availability. Blackbirds did not vary their clutch size in response to predator distributions. These findings generate the potential for an ecological trap in which prey species fail to avoid areas with the highest concentrations of nest predators, or to exhibit behavioural adjustments to reduce the risk of nest predation at such sites. We find some evidence for such ecological traps as, while fine-scale variation in grey squirrel occurrence and activity were not associated with nest predation rates, nests located in closer proximity to corvids and in areas with higher indices of corvid activity experienced slightly higher nest predation rates.
Abstract.
Stanley MC, Beggs JR, Bassett IE, Burns BR, Dirks KN, Jones DN, Linklater WL, Macinnis-Ng C, Simcock R, Souter-Brown G, et al (2015). Emerging threats in urban ecosystems: a horizon scanning exercise.
Frontiers in Ecology and the Environment,
13(10), 553-560.
Abstract:
Emerging threats in urban ecosystems: a horizon scanning exercise
As urbanization intensifies, urban ecosystems are increasingly under pressure from a range of threats. Horizon scanning has the potential to act as an early warning system, thereby initiating prompt discussion and decision making about threat mitigation. We undertook a systematic horizon scanning exercise, using a modified Delphi technique and experts from wide-ranging disciplines, to identify emerging threats in urban ecosystems. The 10 identified threats were generally associated with rapid advances in technology (eg solar panels, light-emitting diode lights, self-healing concrete) or with societal demands on urban nature (eg green prescriptions). Although many of the issues identified are also technological opportunities with recognized environmental benefits, we have highlighted emerging risks so that research and mitigation strategies can be initiated promptly. Given the accelerated rate of technological advancement and the increasing demands of urbanized populations, horizon scanning should be conducted routinely for urban ecosystems.
Abstract.
Yvon-Durocher G, Allen AP, Cellamare M, Dossena M, Gaston KJ, Leitao M, Montoya JM, Reuman DC, Woodward G, Trimmer M, et al (2015). Five Years of Experimental Warming Increases the Biodiversity and Productivity of Phytoplankton.
PLoS Biology,
13(12).
Abstract:
Five Years of Experimental Warming Increases the Biodiversity and Productivity of Phytoplankton
Phytoplankton are key components of aquatic ecosystems, fixing CO2 from the atmosphere through photosynthesis and supporting secondary production, yet relatively little is known about how future global warming might alter their biodiversity and associated ecosystem functioning. Here, we explore how the structure, function, and biodiversity of a planktonic metacommunity was altered after five years of experimental warming. Our outdoor mesocosm experiment was open to natural dispersal from the regional species pool, allowing us to explore the effects of experimental warming in the context of metacommunity dynamics. Warming of 4°C led to a 67% increase in the species richness of the phytoplankton, more evenly-distributed abundance, and higher rates of gross primary productivity. Warming elevated productivity indirectly, by increasing the biodiversity and biomass of the local phytoplankton communities. Warming also systematically shifted the taxonomic and functional trait composition of the phytoplankton, favoring large, colonial, inedible phytoplankton taxa, suggesting stronger top-down control, mediated by zooplankton grazing played an important role. Overall, our findings suggest that temperature can modulate species coexistence, and through such mechanisms, global warming could, in some cases, increase the species richness and productivity of phytoplankton communities.
Abstract.
Bennie J, Duffy JP, Davies TW, Correa-Cano ME, Gaston KJ (2015). Global trends in exposure to light pollution in natural terrestrial ecosystems.
Remote Sensing,
7(3), 2715-2730.
Abstract:
Global trends in exposure to light pollution in natural terrestrial ecosystems
The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000) to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.
Abstract.
Goettsch B, Hilton-Taylor C, Cruz-Piñón G, Duffy JP, Frances A, Hernández HM, Inger R, Pollock C, Schipper J, Superina M, et al (2015). High proportion of cactus species threatened with extinction.
Nature Plants,
1Abstract:
High proportion of cactus species threatened with extinction
A high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groups.
Abstract.
Dallimer M, Davies ZG, Diaz-Porras DF, Irvine KN, Maltby L, Warren PH, Armsworth PR, Gaston KJ (2015). Historical influences on the current provision of multiple ecosystem services.
Global Environmental Change,
31, 307-317.
Abstract:
Historical influences on the current provision of multiple ecosystem services
Ecosystem service provision varies temporally in response to natural and human-induced factors, yet research in this field is dominated by analyses that ignore the time-lags and feedbacks that occur within socio-ecological systems. The implications of this have been unstudied, but are central to understanding how service delivery will alter due to future land-use/cover change. Urban areas are expanding faster than any other land-use, making cities ideal study systems for examining such legacy effects. We assess the extent to which present-day provision of a suite of eight ecosystem services, quantified using field-gathered data, is explained by current and historical (stretching back 150 years) landcover. Five services (above-ground carbon density, recreational use, bird species richness, bird density, and a metric of recreation experience quality (. continuity with the past) were more strongly determined by past landcover. Time-lags ranged from 20 (bird species richness and density) to over 100 years (above-ground carbon density). Historical landcover, therefore, can have a strong influence on current service provision. By ignoring such time-lags, we risk drawing incorrect conclusions regarding how the distribution and quality of some ecosystem services may alter in response to land-use/cover change. Although such a finding adds to the complexity of predicting future scenarios, ecologists may find that they can link the biodiversity conservation agenda to the preservation of cultural heritage, and that certain courses of action provide win-win outcomes across multiple environmental and cultural goods.
Abstract.
Stott I, Soga M, Inger R, Gaston KJ (2015). Land sparing is crucial for urban ecosystem services.
Frontiers in Ecology and the Environment,
13(7), 387-393.
Abstract:
Land sparing is crucial for urban ecosystem services
The world's cities must grow to accommodate an increasing urban population, and achieving this with minimal impact on ecosystem structures and functions is a major challenge. At opposite ends of a possible development spectrum are "land sharing" - extensive sprawling urbanization where built land and natural space are interspersed - and "land sparing" - intensive and extremely compact urbanization alongside separate, large, contiguous green space. Using case studies across urbanization gradients, we demonstrate that land sparing is crucial for sustaining a majority of ecosystem services. Conversely, some land sharing may also be necessary to ensure that people benefit from urban green space. Future urban development should carefully consider green space provision, to maximize the services provided by urban ecosystems. This can be achieved by optimizing distributions of development intensity across cities by means of top-down, policy-led approaches.
Abstract.
Mitchell MGE, Suarez-Castro AF, Martinez-Harms M, Maron M, McAlpine C, Gaston KJ, Johansen K, Rhodes JR (2015). Landscape Fragmentation and Ecosystem Services: a Reply to Andrieu et al.
Trends Ecol Evol,
30(11), 634-635.
Author URL.
Cox DTC, Gaston KJ (2015). Likeability of Garden Birds: Importance of Species Knowledge & Richness in Connecting People to Nature.
PLoS One,
10(11).
Abstract:
Likeability of Garden Birds: Importance of Species Knowledge & Richness in Connecting People to Nature.
Interacting with nature is widely recognised as providing many health and well-being benefits. As people live increasingly urbanised lifestyles, the provision of food for garden birds may create a vital link for connecting people to nature and enabling them to access these benefits. However, it is not clear which factors determine the pleasure that people receive from watching birds at their feeders. These may be dependent on the species that are present, the abundance of individuals and the species richness of birds around the feeders. We quantitatively surveyed urban households from towns in southern England to determine the factors that influence the likeability of 14 common garden bird species, and to assess whether people prefer to see a greater abundance of individuals or increased species richness at their feeders. There was substantial variation in likeability across species, with songbirds being preferred over non-songbirds. Species likeability increased for people who fed birds regularly and who could name the species. We found a strong correlation between the number of species that a person could correctly identify and how connected to nature they felt when they watched garden birds. Species richness was preferred over a greater number of individuals of the same species. Although we do not show causation this study suggests that it is possible to increase the well-being benefits that people gain from watching birds at their feeders. This could be done first through a human to bird approach by encouraging regular interactions between people and their garden birds, such as through learning the species names and providing food. Second, it could be achieved through a bird to human approach by increasing garden songbird diversity because the pleasure that a person receives from watching an individual bird at a feeder is dependent not only on its species but also on the diversity of birds at the feeder.
Abstract.
Author URL.
Chown SL, Gaston KJ (2015). Macrophysiology - progress and prospects.
Functional EcologyAbstract:
Macrophysiology - progress and prospects
© 2015 the Authors. Macrophysiology is the investigation of variation in physiological traits over large geographic and temporal scales and the ecological implications of this variation. It has now been undertaken, as a defined field, for a decade. Here, we overview its conceptual foundations, methodological approaches and insights, together with challenges the field is facing currently. Macrophysiology builds on approaches that investigate the ecological and evolutionary significance of physiological trait variation and feedbacks in these processes. One of its key strengths is its ability to provide a basis for examining interactions among the intraspecific, interspecific and assemblage levels. Macrophysiology is distinct from and typically concerns larger spatial and temporal scales than conservation physiology, whereas it is in several respects similar to, but antecedes, functional biogeography. Contrary to some claims, macrophysiology is not concerned only with the implications for geographic ranges of physiological trait variation. Several insights, which would not otherwise have been achieved, have arisen from the field, notably the understanding of variation in global patterns of upper and lower lethal temperature limits and organism performance, which have important implications for forecasting the impacts of climate change. Ten major challenges are identified for the field of macroecology, including better integration of approaches and information for plants and animals. Nonetheless, the prospects for macrophysiology as a significant way to understand our world remain bright.
Abstract.
Duffy JP, Bennie J, Durán AP, Gaston KJ (2015). Mammalian ranges are experiencing erosion of natural darkness.
Sci Rep,
5Abstract:
Mammalian ranges are experiencing erosion of natural darkness.
The continuous increase in the intensity and extent of anthropogenic artificial light has significantly shaped Earth's nighttime environment. This environmental change has effects across the natural world, with consequences for organismal physiology and behaviour and the abundances and distributions of species. Here, we evaluate for the first time the relations between the spatio-temporal patterns of anthropogenic nighttime light and the distribution of terrestrial mammals, one of the most endangered species groups and one that expresses varying time partitioning strategies. Using descriptive statistics, trend tests and spatial prioritization analysis we show that in most places on earth there is a terrestrial mammal species whose range is experiencing detectable artificial light. For most species this tends only to be for small parts of their range, and those affected across large parts are typically rare. Over time (1992-2012), an increase in mean light intensity was found for the ranges of the majority of species, with very few experiencing a decrease. Moreover, nocturnal species are more likely to experience an increase in light within their ranges. This is of conservation concern as many terrestrial mammals are nocturnal and therefore often particularly vulnerable to a pressure such as artificial light at night.
Abstract.
Author URL.
Mchugh N, Edmondson JL, Gaston KJ, Leake JR, O'Sullivan OS (2015). Modelling short-rotation coppice and tree planting for urban carbon management - a citywide analysis.
Journal of Applied EcologyAbstract:
Modelling short-rotation coppice and tree planting for urban carbon management - a citywide analysis
The capacity of urban areas to deliver provisioning ecosystem services is commonly overlooked and underutilized. Urban populations have globally increased fivefold since 1950, and they disproportionately consume ecosystem services and contribute to carbon emissions, highlighting the need to increase urban sustainability and reduce environmental impacts of urban dwellers. Here, we investigated the potential for increasing carbon sequestration, and biomass fuel production, by planting trees and short-rotation coppice (SRC), respectively, in a mid-sized UK city as a contribution to meeting national commitments to reduce CO2 emissions. Iterative GIS models were developed using high-resolution spatial data. The models were applied to patches of public and privately owned urban greenspace suitable for planting trees and SRC, across the 73 km2 area of the city of Leicester. We modelled tree planting with a species mix based on the existing tree populations, and SRC with willow and poplar to calculate biomass production in new trees, and carbon sequestration into harvested biomass over 25 years. An area of 11 km2 comprising 15% of the city met criteria for tree planting and had the potential over 25 years to sequester 4200 tonnes of carbon above-ground. of this area, 5·8 km2 also met criteria for SRC planting and over the same period this could yield 71 800 tonnes of carbon in harvested biomass. The harvested biomass could supply energy to over 1566 domestic homes or 30 municipal buildings, resulting in avoided carbon emissions of 29 236 tonnes of carbon over 25 years when compared to heating by natural gas. Together with the net carbon sequestration into trees, a total reduction of 33 419 tonnes of carbon in the atmosphere could be achieved in 25 years by combined SRC and tree planting across the city. Synthesis and applications. We demonstrate that urban greenspaces in a typical UK city are underutilized for provisioning ecosystem services by trees and especially SRC, which has high biomass production potential. For urban greenspace management, we recommend that planting SRC in urban areas can contribute to reducing food-fuel conflicts on agricultural land and produce renewable energy sources close to centres of population and demand.
Abstract.
Day J, Baker J, Schofield H, Mathews F, Gaston KJ (2015). Part-night lighting: Implications for bat conservation.
Animal ConservationAbstract:
Part-night lighting: Implications for bat conservation
© 2015 the Zoological Society of London. Artificial nighttime lighting has many effects on biodiversity. A proposed environmental management option, primarily to save energy, is to alter the duration of night lighting. Using the greater horseshoe bat Rhinolophus ferrumequinum as an example of a photophobic species, we explored roadside behaviour patterns throughout the night to assess the potential impact of part-night lighting. We found a large primary peak in activity 1h after sunset, followed by a smaller secondary peak before sunrise. Simulated part-night lighting scenarios reveal that to capture a large proportion of bat activity, streetlights should be switched off before midnight. Current proposed uses of part-night lighting are unlikely to capture natural peaks in activity for nocturnal species.
Abstract.
Gaston KJ, Duffy JP, Bennie J (2015). Quantifying the erosion of natural darkness in the global protected area system.
Conserv Biol,
29(4), 1132-1141.
Abstract:
Quantifying the erosion of natural darkness in the global protected area system.
The nighttime light environment of much of the earth has been transformed by the introduction of electric lighting. This impact continues to spread with growth in the human population and extent of urbanization. This has profound consequences for organismal physiology and behavior and affects abundances and distributions of species, community structure, and likely ecosystem functions and processes. Protected areas play key roles in buffering biodiversity from a wide range of anthropogenic pressures. We used a calibration of a global satellite data set of nighttime lights to determine how well they are fulfilling this role with regard to artificial nighttime lighting. Globally, areas that are protected tend to be darker at night than those that are not, and, with the exception of Europe, recent regional declines in the proportion of the area that is protected and remains dark have been small. However, much of these effects result from the major contribution to overall protected area coverage by the small proportion of individual protected areas that are very large. Thus, in Europe and North America high proportions of individual protected areas (>17%) have exhibited high levels of nighttime lighting in all recent years, and in several regions (Europe, Asia, South and Central America) high proportions of protected areas (32-42%) have had recent significant increases in nighttime lighting. Limiting and reversing the erosion of nighttime darkness in protected areas will require routine consideration of nighttime conditions when designating and establishing new protected areas; establishment of appropriate buffer zones around protected areas where lighting is prohibited; and landscape level reductions in artificial nighttime lighting, which is being called for in general to reduce energy use and economic costs.
Abstract.
Author URL.
Soga M, Yamaura Y, Aikoh T, Shoji Y, Kubo T, Gaston KJ (2015). Reducing the extinction of experience: Association between urban form and recreational use of public greenspace.
Landscape and Urban Planning,
143, 69-75.
Abstract:
Reducing the extinction of experience: Association between urban form and recreational use of public greenspace
Halting the 'extinction of experience', the progressive disengagement of people with the natural world, is vital to human health and wellbeing and to public support for global biological conservation. Home to the majority of humanity, urban areas are the key for engaging people with nature, raising the crucial question of how cities should best be designed to facilitate these experiences. For the purposes of maintaining local biodiversity, intensive development within a small area (land sparing) has been shown to be better than extensive development over a large area (land sharing). Here, we investigated for the first time how different city forms affect people's experience of nature, measured in terms of their use of greenspaces. We selected five pairs of land-sharing and land-sparing study regions with different coverage by greenspaces within the city of Tokyo, central Japan and used a questionnaire survey to determine the use residents made of these spaces. We found the frequency of people's recreational use of urban greenspaces was higher in urban land-sharing than land-sparing regions. Moreover, satisfaction with local green environments was also higher in land-sharing regions. This suggests a potential conflict in the design of cities between the urban form that is most desirable for the direct protection of regional biodiversity, and that which best promotes people's nature experiences and the support for its wider protection. A strong emphasis on the advantages of land sparing may increase the separation of humans from nature, and further reduce public interest in, and awareness of, biodiversity and its benefits.
Abstract.
Mitchell MGE, Suarez-Castro AF, Martinez-Harms M, Maron M, McAlpine C, Gaston KJ, Johansen K, Rhodes JR (2015). Reframing landscape fragmentation's effects on ecosystem services.
Trends Ecol Evol,
30(4), 190-198.
Abstract:
Reframing landscape fragmentation's effects on ecosystem services.
Landscape structure and fragmentation have important effects on ecosystem services, with a common assumption being that fragmentation reduces service provision. This is based on fragmentation's expected effects on ecosystem service supply, but ignores how fragmentation influences the flow of services to people. Here we develop a new conceptual framework that explicitly considers the links between landscape fragmentation, the supply of services, and the flow of services to people. We argue that fragmentation's effects on ecosystem service flow can be positive or negative, and use our framework to construct testable hypotheses about the effects of fragmentation on final ecosystem service provision. Empirical efforts to apply and test this framework are critical to improving landscape management for multiple ecosystem services.
Abstract.
Author URL.
Edmondson JL, Gaston KJ, Leake JR (2015). Soil and the city. Frontiers in Ecology and the Environment, 13(5).
Durán AP, Inger R, Cantú-Salazar L, Gaston KJ (2015). Species richness representation within protected areas is associated with multiple interacting spatial features.
Diversity and DistributionsAbstract:
Species richness representation within protected areas is associated with multiple interacting spatial features
© 2015 John Wiley & Sons Ltd. Aim: to assess the relative effects of the spatial features of protected areas (PAs), and their interactions, on species richness representation. Location: Continental America and associated islands. Methods: We used a novel dataset comprising species richness estimates for amphibians, birds and mammals for more than 400 PAs in the Western Hemisphere. Using spatial tools and remote sensing imagery, we calculated four spatial features for each PA: size, shape index, fragmentation level and proximity to the closest PA. The relative effect size of both PA spatial features and environmental covariates on levels of species richness, and how they interact, were assessed using generalized mixed effect models. Results: Spatial features and environmental covariates explained about 61% of the variation in species richness within PAs, with the magnitude of the effect remaining similar among spatial features and taxonomic groups. While area had a positive effect on species richness, shape index and fragmentation had negative effects. Proximity had a significant positive effect only for mammals and a negative effect for all the taxa combined. PA spatial features showed significant interactions between them and with environmental covariates. Main conclusions: We provide the first empirical evidence for the combined and interactive effects of terrestrial PA spatial features on predicting species richness. Our results suggest that the spatial features of PAs have an important effect on species richness and while the magnitude of this effect varies across taxonomic groups, its direction is consistent. Additionally, we show that the effect of one spatial design feature can be amplified or attenuated by that of another. These findings contribute towards a better understanding of the effect of spatial features on the performance of PAs and therefore how best to enhance the spatial configuration of existing and future PAs.
Abstract.
Gaston KJ, Visser ME, Hölker F (2015). The biological impacts of artificial light at night: the research challenge.
Philos Trans R Soc Lond B Biol Sci,
370(1667).
Author URL.
Porcelli D, Butlin RK, Gaston KJ, Joly D, Snook RR (2015). The environmental genomics of metazoan thermal adaptation.
Heredity,
114(5), 502-514.
Abstract:
The environmental genomics of metazoan thermal adaptation
Continued and accelerating change in the thermal environment places an ever-greater priority on understanding how organisms are going to respond. The paradigm of 'move, adapt or die', regarding ways in which organisms can respond to environmental stressors, stimulates intense efforts to predict the future of biodiversity. Assuming that extinction is an unpalatable outcome, researchers have focussed attention on how organisms can shift in their distribution to stay in the same thermal conditions or can stay in the same place by adapting to a changing thermal environment. How likely these respective outcomes might be depends on the answer to a fundamental evolutionary question, namely what genetic changes underpin adaptation to the thermal environment. The increasing access to and decreasing costs of next-generation sequencing (NGS) technologies, which can be applied to both model and non-model systems, provide a much-needed tool for understanding thermal adaptation. Here we consider broadly what is already known from non-NGS studies about thermal adaptation, then discuss the benefits and challenges of different NGS methodologies to add to this knowledge base. We then review published NGS genomics and transcriptomics studies of thermal adaptation to heat stress in metazoans and compare these results with previous non-NGS patterns. We conclude by summarising emerging patterns of genetic response and discussing future directions using these increasingly common techniques.
Abstract.
Porcelli D, Butlin RK, Gaston KJ, Joly D, Snook RR (2015). The environmental genomics of metazoan thermal adaptation.
Heredity (Edinb),
114(5), 502-514.
Abstract:
The environmental genomics of metazoan thermal adaptation.
Continued and accelerating change in the thermal environment places an ever-greater priority on understanding how organisms are going to respond. The paradigm of 'move, adapt or die', regarding ways in which organisms can respond to environmental stressors, stimulates intense efforts to predict the future of biodiversity. Assuming that extinction is an unpalatable outcome, researchers have focussed attention on how organisms can shift in their distribution to stay in the same thermal conditions or can stay in the same place by adapting to a changing thermal environment. How likely these respective outcomes might be depends on the answer to a fundamental evolutionary question, namely what genetic changes underpin adaptation to the thermal environment. The increasing access to and decreasing costs of next-generation sequencing (NGS) technologies, which can be applied to both model and non-model systems, provide a much-needed tool for understanding thermal adaptation. Here we consider broadly what is already known from non-NGS studies about thermal adaptation, then discuss the benefits and challenges of different NGS methodologies to add to this knowledge base. We then review published NGS genomics and transcriptomics studies of thermal adaptation to heat stress in metazoans and compare these results with previous non-NGS patterns. We conclude by summarising emerging patterns of genetic response and discussing future directions using these increasingly common techniques.
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Author URL.
Gómez P, Bennie J, Gaston KJ, Buckling A (2015). The impact of resource availability on bacterial resistance to phages in soil.
PLoS One,
10(4).
Abstract:
The impact of resource availability on bacterial resistance to phages in soil.
Resource availability can affect the coevolutionary dynamics between host and parasites, shaping communities and hence ecosystem function. A key finding from theoretical and in vitro studies is that host resistance evolves to greater levels with increased resources, but the relevance to natural communities is less clear. We took two complementary approaches to investigate the effect of resource availability on the evolution of bacterial resistance to phages in soil. First, we measured the resistance and infectivity of natural communities of soil bacteria and phage in the presence and absence of nutrient-providing plants. Second, we followed the real-time coevolution between defined bacteria and phage populations with resource availability manipulated by the addition or not of an artificial plant root exudate. Increased resource availability resulted in increases in bacterial resistance to phages, but without a concomitant increase in phage infectivity. These results suggest that phages may have a reduced impact on the control of bacterial densities and community composition in stable, high resource environments.
Abstract.
Author URL.
Shanahan DF, Lin BB, Bush R, Gaston KJ, Dean JH, Barber E, Fuller RA (2015). Toward improved public health outcomes from urban nature.
Am J Public Health,
105(3), 470-477.
Abstract:
Toward improved public health outcomes from urban nature.
There is mounting concern for the health of urban populations as cities expand at an unprecedented rate. Urban green spaces provide settings for a remarkable range of physical and mental health benefits, and pioneering health policy is recognizing nature as a cost-effective tool for planning healthy cities. Despite this, limited information on how specific elements of nature deliver health outcomes restricts its use for enhancing population health. We articulate a framework for identifying direct and indirect causal pathways through which nature delivers health benefits, and highlight current evidence. We see a need for a bold new research agenda founded on testing causality that transcends disciplinary boundaries between ecology and health. This will lead to cost-effective and tailored solutions that could enhance population health and reduce health inequalities.
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Author URL.
Hancock S, Armston J, Li Z, Gaulton R, Lewis P, Disney M, Mark Danson F, Strahler A, Schaaf C, Anderson K, et al (2015). Waveform lidar over vegetation: an evaluation of inversion methods for estimating return energy.
Remote Sensing of Environment,
164, 208-224.
Abstract:
Waveform lidar over vegetation: an evaluation of inversion methods for estimating return energy
Full waveform lidar has a unique capability to characterise vegetation in more detail than any other practical method. The reflectance, calculated from the energy of lidar returns, is a key parameter for a wide range of applications and so it is vital to extract it accurately. Fifteen separate methods have been proposed to extract return energy (the amount of light backscattered from a target), ranging from simple to mathematically complex, but the relative accuracies have not yet been assessed. This paper uses a simulator to compare all methods over a wide range of targets and lidar system parameters. For hard targets the simplest methods (windowed sum, peak and quadratic) gave the most consistent estimates. They did not have high accuracies, but low standard deviations show that they could be calibrated to give accurate energy. This may be why some commercial lidar developers use them, where the primary interest is in surveying solid objects. However, simulations showed that these methods are not appropriate over vegetation. The widely used Gaussian fitting performed well over hard targets (0.24% root mean square error, RMSE), as did the sum and spline methods (0.30% RMSE). Over vegetation, for large footprint (15 m) systems, Gaussian fitting performed the best (12.2% RMSE) followed closely by the sum and spline (both 12.7% RMSE). For smaller footprints (33. cm and 1. cm) over vegetation, the relative accuracies were reversed (0.56% RMSE for the sum and spline and 1.37% for Gaussian fitting). Gaussian fitting required heavy smoothing (convolution with an 8 m Gaussian) whereas none was needed for the sum and spline. These simpler methods were also more robust to noise and far less computationally expensive than Gaussian fitting. Therefore it was concluded that the sum and spline were the most accurate for extracting return energy from waveform lidar over vegetation, except for large footprint (15 m), where Gaussian fitting was slightly more accurate. These results suggest that small footprint (≪ 15 m) lidar systems that use Gaussian fitting or proprietary algorithms may report inaccurate energies, and thus reflectances, over vegetation. In addition the effect of system pulse length, sampling interval and noise on accuracy for different targets was assessed, which has implications for sensor design.
Abstract.
Kyba CCM, Tong KP, Bennie J, Birriel I, Birriel JJ, Cool A, Danielsen A, Davies TW, Outer PND, Edwards W, et al (2015). Worldwide variations in artificial skyglow.
Sci Rep,
5Abstract:
Worldwide variations in artificial skyglow.
Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.
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Author URL.
Díaz-Porras DF, Gaston KJ, Evans KL (2014). 110 Years of change in urban tree stocks and associated carbon storage.
Ecology and Evolution,
4(8), 1413-1422.
Abstract:
110 Years of change in urban tree stocks and associated carbon storage
Understanding the long-term dynamics of urban vegetation is essential in determining trends in the provision of key resources for biodiversity and ecosystem services and improving their management. Such studies are, however, extremely scarce due to the lack of suitable historical data. We use repeat historical photographs from the 1900s, 1950s, and 2010 to assess general trends in the quantity and size distributions of the tree stock in urban Sheffield and resultant aboveground carbon storage. Total tree numbers declined by a third from the 1900s to the 1950s, but increased by approximately 50% from the 1900s-2010, and by 100% from the 1950s-2010. Aboveground carbon storage in urban tree stocks had doubled by 2010 from the levels present in the 1900s and 1950s. The initial decrease occurred at a time when national and regional tree stocks were static and are likely to be driven by rebuilding following bombing of the urban area during the Second World War and by urban expansion. In 2010, trees greater than 10 m in height comprised just 8% of those present. The increases in total tree numbers are thus largely driven by smaller trees and are likely to be associated with urban tree planting programmes. Changes in tree stocks were not constant across the urban area but varied with the current intensity of urbanization. Increases from 1900 to 2010 in total tree stocks, and smaller sized trees, tended to be greatest in the most intensely urbanized areas. In contrast, the increases in the largest trees were more marked in areas with the most green space. These findings emphasize the importance of preserving larger fragments of urban green space to protect the oldest and largest trees that contribute disproportionately to carbon storage and other ecosystem services. Maintaining positive trends in urban tree stocks and associated ecosystem service provision will require continued investment in urban tree planting programmes in combination with additional measures, such as revisions to tree preservation orders, to increase the retention of such trees as they mature. © 2014 the Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
Abstract.
Bonnington C, Gaston KJ, Evans KL (2014). Assessing the potential for Grey Squirrels Sciurus carolinensis to compete with birds at supplementary feeding stations.
Ibis,
156(1), 220-226.
Abstract:
Assessing the potential for Grey Squirrels Sciurus carolinensis to compete with birds at supplementary feeding stations
Supplementary feeding of birds, particularly in urban areas, is often associated with increased population size and fecundity. In the UK, the non-native Grey Squirrel Sciurus carolinensis is common in rural and urban habitats. It exploits supplementary feeders and may induce interference competition by excluding birds, but empirical evidence of this is unavailable. Using controlled model presentation experiments, we demonstrate that Grey Squirrels could reduce bird use of supplementary feeders and induce interference competition. Total bird resource use was reduced by 98% and most species exhibited similar sensitivities. The likelihood and magnitude of interference competition will depend on how rapidly displaced birds find alternative food sources; it will be greatest where there are high Grey Squirrel densities and few supplementary feeders. Other studies suggest that supplementary feeding increases Grey Squirrel numbers, and the species is also predicted to expand its non-native range across most of Europe. Our data indicate that Grey Squirrels may eventually alter the net effect of supplementary feeding on bird populations across the European continent; increased use of squirrel-proof feeders may help to minimize such effects. © 2013 British Ornithologists' Union.
Abstract.
Bennie JJ, Duffy JP, Inger R, Gaston KJ (2014). Biogeography of time partitioning in mammals.
Proc Natl Acad Sci U S A,
111(38), 13727-13732.
Abstract:
Biogeography of time partitioning in mammals.
Many animals regulate their activity over a 24-h sleep-wake cycle, concentrating their peak periods of activity to coincide with the hours of daylight, darkness, or twilight, or using different periods of light and darkness in more complex ways. These behavioral differences, which are in themselves functional traits, are associated with suites of physiological and morphological adaptations with implications for the ecological roles of species. The biogeography of diel time partitioning is, however, poorly understood. Here, we document basic biogeographic patterns of time partitioning by mammals and ecologically relevant large-scale patterns of natural variation in "illuminated activity time" constrained by temperature, and we determine how well the first of these are predicted by the second. Although the majority of mammals are nocturnal, the distributions of diurnal and crepuscular species richness are strongly associated with the availability of biologically useful daylight and twilight, respectively. Cathemerality is associated with relatively long hours of daylight and twilight in the northern Holarctic region, whereas the proportion of nocturnal species is highest in arid regions and lowest at extreme high altitudes. Although thermal constraints on activity have been identified as key to the distributions of organisms, constraints due to functional adaptation to the light environment are less well studied. Global patterns in diversity are constrained by the availability of the temporal niche; disruption of these constraints by the spread of artificial lighting and anthropogenic climate change, and the potential effects on time partitioning, are likely to be critical influences on species' future distributions.
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Author URL.
Bennie J, Davies TW, Duffy JP, Inger R, Gaston KJ (2014). Contrasting trends in light pollution across Europe based on satellite observed night time lights.
Sci Rep,
4Abstract:
Contrasting trends in light pollution across Europe based on satellite observed night time lights.
Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits.
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Author URL.
Gaston KJ, Bennie J (2014). Demographic effects of artificial nighttime lighting on animal populations.
Environmental Reviews,
22(4), 323-330.
Abstract:
Demographic effects of artificial nighttime lighting on animal populations
Artificial lighting, especially but not exclusively through street lights, has transformed the nighttime environment in much of the world. Impacts have been identified across multiple levels of biological organization and process. The influences, however, on population dynamics, particularly through the combined effects on the key demographic rates (immigration, births, deaths, emigration) that determine where individual species occur and in what numbers, have not previously been well characterized. The majority of attention explicitly on demographic parameters to date has been placed on the attraction of organisms to lights, and thus effectively local immigration, the large numbers of individuals that can be involved, and then to some extent the mortality that can often result. Some of the most important influences of nighttime lighting, however, are likely more subtle and less immediately apparent to the human observer. Particularly significant are effects of nighttime lighting on demography that act through (i) circadian clocks and photoperiodism and thence on birth rates; (ii) time partitioning and thence on death rates; and (iii) immigration/emigration through constraining the movements of individuals amongst habitat networks, especially as a consequence of continuously lit linear features such as roads and footpaths. Good model organisms are required to enable the relative consequences of such effects to be effectively determined, and a wider consideration of the effects of artificial light at night is needed in demographic studies across a range of species.
Abstract.
Durán AP, Duffy JP, Gaston KJ (2014). Exclusion of agricultural lands in spatial conservation prioritization strategies: consequences for biodiversity and ecosystem service representation.
Proc Biol Sci,
281(1792).
Abstract:
Exclusion of agricultural lands in spatial conservation prioritization strategies: consequences for biodiversity and ecosystem service representation.
Agroecosystems have traditionally been considered incompatible with biological conservation goals, and often been excluded from spatial conservation prioritization strategies. The consequences for the representativeness of identified priority areas have been little explored. Here, we evaluate these for biodiversity and carbon storage representation when agricultural land areas are excluded from a spatial prioritization strategy for South America. Comparing different prioritization approaches, we also assess how the spatial overlap of priority areas changes. The exclusion of agricultural lands was detrimental to biodiversity representation, indicating that priority areas for agricultural production overlap with areas of relatively high occurrence of species. By contrast, exclusion of agricultural lands benefits representation of carbon storage within priority areas, as lands of high value for agriculture and carbon storage overlap little. When agricultural lands were included and equally weighted with biodiversity and carbon storage, a balanced representation resulted. Our findings suggest that with appropriate management, South American agroecosystems can significantly contribute to biodiversity conservation.
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Author URL.
Gaston KJ, Duffy JP, Gaston S, Bennie J, Davies TW (2014). Human alteration of natural light cycles: causes and ecological consequences.
Oecologia,
176(4), 917-931.
Abstract:
Human alteration of natural light cycles: causes and ecological consequences.
Artificial light at night is profoundly altering natural light cycles, particularly as perceived by many organisms, over extensive areas of the globe. This alteration comprises the introduction of light at night at places and times at which it has not previously occurred, and with different spectral signatures. Given the long geological periods for which light cycles have previously been consistent, this constitutes a novel environmental pressure, and one for which there is evidence for biological effects that span from molecular to community level. Here we provide a synthesis of understanding of the form and extent of this alteration, some of the key consequences for terrestrial and aquatic ecosystems, interactions and synergies with other anthropogenic pressures on the environment, major uncertainties, and future prospects and management options. This constitutes a compelling example of the need for a thoroughly interdisciplinary approach to understanding and managing the impact of one particular anthropogenic pressure. The former requires insights that span molecular biology to ecosystem ecology, and the latter contributions of biologists, policy makers and engineers.
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Author URL.
Soga M, Yamaura Y, Koike S, Gaston KJ (2014). Land sharing vs. land sparing: Does the compact city reconcile urban development and biodiversity conservation?. Journal of Applied Ecology
Edmondson JL, Davies ZG, McCormack SA, Gaston KJ, Leake JR (2014). Land-cover effects on soil organic carbon stocks in a European city.
Sci Total Environ,
472, 444-453.
Abstract:
Land-cover effects on soil organic carbon stocks in a European city.
Soil is the vital foundation of terrestrial ecosystems storing water, nutrients, and almost three-quarters of the organic carbon stocks of the Earth's biomes. Soil organic carbon (SOC) stocks vary with land-cover and land-use change, with significant losses occurring through disturbance and cultivation. Although urbanisation is a growing contributor to land-use change globally, the effects of urban land-cover types on SOC stocks have not been studied for densely built cities. Additionally, there is a need to resolve the direction and extent to which greenspace management such as tree planting impacts on SOC concentrations. Here, we analyse the effect of land-cover (herbaceous, shrub or tree cover), on SOC stocks in domestic gardens and non-domestic greenspaces across a typical mid-sized U.K. city (Leicester, 73 km(2), 56% greenspace), and map citywide distribution of this ecosystem service. SOC was measured in topsoil and compared to surrounding extra-urban agricultural land. Average SOC storage in the city's greenspace was 9.9 kg m(-2), to 21 cm depth. SOC concentrations under trees and shrubs in domestic gardens were greater than all other land-covers, with total median storage of 13.5 kg m(-2) to 21 cm depth, more than 3 kg m(-2) greater than any other land-cover class in domestic and non-domestic greenspace and 5 kg m(-2) greater than in arable land. Land-cover did not significantly affect SOC concentrations in non-domestic greenspace, but values beneath trees were higher than under both pasture and arable land, whereas concentrations under shrub and herbaceous land-covers were only higher than arable fields. We conclude that although differences in greenspace management affect SOC stocks, trees only marginally increase these stocks in non-domestic greenspaces, but may enhance them in domestic gardens, and greenspace topsoils hold substantial SOC stores that require protection from further expansion of artificial surfaces e.g. patios and driveways.
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Author URL.
Coetzee BWT, Gaston KJ, Chown SL (2014). Local scale comparisons of biodiversity as a test for global protected area ecological performance: a meta-analysis.
PLoS One,
9(8).
Abstract:
Local scale comparisons of biodiversity as a test for global protected area ecological performance: a meta-analysis.
Terrestrial protected areas (PAs) are cornerstones of global biodiversity conservation. Their efficacy in terms of maintaining biodiversity is, however, much debated. Studies to date have been unable to provide a general answer as to PA conservation efficacy because of their typically restricted geographic and/or taxonomic focus, or qualitative approaches focusing on proxies for biodiversity, such as deforestation. Given the rarity of historical data to enable comparisons of biodiversity before/after PA establishment, many smaller scale studies over the past 30 years have directly compared biodiversity inside PAs to that of surrounding areas, which provides one measure of PA ecological performance. Here we use a meta-analysis of such studies (N = 86) to test if PAs contain higher biodiversity values than surrounding areas, and so assess their contribution to determining PA efficacy. We find that PAs generally have higher abundances of individual species, higher assemblage abundances, and higher species richness values compared with alternative land uses. Local scale studies in combination thus show that PAs retain more biodiversity than alternative land use areas. Nonetheless, much variation is present in the effect sizes, which underscores the context-specificity of PA efficacy.
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Author URL.
Bennie J, Davies TW, Inger R, Gaston KJ (2014). Mapping artificial lightscapes for ecological studies.
Methods in Ecology and Evolution,
5(6), 534-540.
Abstract:
Mapping artificial lightscapes for ecological studies
Summary: Artificial illumination of the night is increasing globally. There is growing evidence of a range of ecological impacts of artificial light and awareness of light pollution as a significant environmental issue. In urban and suburban areas, complex spatial patterns of light sources, structures and vegetation create a highly heterogeneous night-time light environment for plants and animals. We developed a method for modelling the night-time light environment at a high spatial resolution in a small urban area for ecological studies. We used the position and height of street lights, and digital terrain and surface models, to predict the direct light intensity at different wavelengths at different heights above the ground surface. Validation against field measurements of night-time light showed that modelled light intensities in the visible and ultraviolet portions of the spectrum were accurate. We show how this model can be used to map biologically relevant lightscapes across an urban landscape. We also illustrate the utility of the model using night-time light maps as resistance surfaces in the software package circuitscape to predict potential movement of model nocturnal species between habitat patches and to identify key corridors and barriers to movement and dispersal. Understanding the ecological effects of artificial light requires knowledge of the light environment experienced by organisms throughout the diurnal and annual cycles, during periods of activity and rest and during different life stages. Our approach to high-resolution mapping of artificial lightscapes can be adapted to the sensitivity to light of different species and to other urban, suburban, rural and industrial landscapes. © 2014 the Authors.
Abstract.
Lin BB, Fuller RA, Bush R, Gaston KJ, Shanahan DF (2014). Opportunity or orientation? Who uses urban parks and why.
PLoS One,
9(1).
Abstract:
Opportunity or orientation? Who uses urban parks and why.
There is growing recognition that interactions with nature provide many desirable human well-being outcomes, yet increasing urbanization is degrading the quality and quantity of nature experiences. Thus, it has become increasingly important to understand how and why urban dwellers interact with nature. Studies of urban green space use have largely focused on the availability and ease of access to green space, suggesting that greater opportunities to experience such space will lead to increased use. However, a growing literature emphasizes the potential for an individual's nature orientation to affect their interaction with green space. Here we measure the importance of both opportunity and orientation factors in explaining urban park use. An urban lifestyle survey was deployed across Brisbane, Australia in November 2012 to assess patterns of green space use. Participants (n=1479) were asked to provide information on demographics, private yard use, park visitations in the past week, and their orientation toward nature. About 60% of those surveyed had visited a park in the past week, and while this park user population had significantly greater nearby park coverage (within a 250 m radius; p=0.006), a much stronger determinant of visitation was their higher nature orientation (p
Abstract.
Author URL.
Inger R, Bennie J, Davies TW, Gaston KJ (2014). Potential biological and ecological effects of flickering artificial light.
PLoS One,
9(5).
Abstract:
Potential biological and ecological effects of flickering artificial light.
Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered.
Abstract.
Author URL.
Dallimer M, Tinch D, Hanley N, Irvine KN, Rouquette JR, Warren PH, Maltby L, Gaston KJ, Armsworth PR (2014). Quantifying preferences for the natural world using monetary and nonmonetary assessments of value.
Conservation Biology,
28(2), 404-413.
Abstract:
Quantifying preferences for the natural world using monetary and nonmonetary assessments of value
Given that funds for biodiversity conservation are limited, there is a need to understand people's preferences for its different components. To date, such preferences have largely been measured in monetary terms. However, how people value biodiversity may differ from economic theory, and there is little consensus over whether monetary metrics are always appropriate or the degree to which other methods offer alternative and complementary perspectives on value. We used a choice experiment to compare monetary amounts recreational visitors to urban green spaces were willing to pay for biodiversity enhancement (increases in species richness for birds, plants, and aquatic macroinvertebrates) with self-reported psychological gains in well-being derived from visiting the same sites. Willingness-to-pay (WTP) estimates were significant and positive, and respondents reported high gains in well-being across 3 axes derived from environmental psychology theories (reflection, attachment, continuity with past). The 2 metrics were broadly congruent. Participants with above-median self-reported well-being scores were willing to pay significantly higher amounts for enhancing species richness than those with below-median scores, regardless of taxon. The socio-economic and demographic background of participants played little role in determining either their well-being or the probability of choosing a paying option within the choice experiment. Site-level environmental characteristics were only somewhat related to WTP, but showed strong associations with self-reported well-being. Both approaches are likely to reflect a combination of the environmental properties of a site and unobserved individual preference heterogeneity for the natural world. Our results suggest that either metric will deliver mutually consistent results in an assessment of environmental preferences, although which approach is preferable depends on why one wishes to measure values for the natural world. © 2013 the Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of the Society for Conservation Biology.
Abstract.
Gaston KJ, Gaston S, Bennie J, Hopkins J (2014). Reducing the impacts of artificial light. British Wildlife, 25(5), 332-339.
Casalegno S, Bennie JJ, Inger R, Gaston KJ (2014). Regional scale prioritisation for key ecosystem services, renewable energy production and urban development.
PLoS One,
9(9).
Abstract:
Regional scale prioritisation for key ecosystem services, renewable energy production and urban development.
Although the importance of addressing ecosystem service benefits in regional land use planning and decision-making is evident, substantial practical challenges remain. In particular, methods to identify priority areas for the provision of key ecosystem services and other environmental services (benefits from the environment not directly linked to the function of ecosystems) need to be developed. Priority areas are locations which provide disproportionally high benefits from one or more service. Here we map a set of ecosystem and environmental services and delineate priority areas according to different scenarios. Each scenario is produced by a set of weightings allocated to different services and corresponds to different landscape management strategies which decision makers could undertake. Using the county of Cornwall, U.K. as a case study, we processed gridded maps of key ecosystem services and environmental services, including renewable energy production and urban development. We explored their spatial distribution patterns and their spatial covariance and spatial stationarity within the region. Finally we applied a complementarity-based priority ranking algorithm (zonation) using different weighting schemes. Our conclusions are that (i) there are two main patterns of service distribution in this region, clustered services (including agriculture, carbon stocks, urban development and plant production) and dispersed services (including cultural services, energy production and floods mitigation); (ii) more than half of the services are spatially correlated and there is high non-stationarity in the spatial covariance between services; and (iii) it is important to consider both ecosystem services and other environmental services in identifying priority areas. Different weighting schemes provoke drastic changes in the delineation of priority areas and therefore decision making processes need to carefully consider the relative values attributed to different services.
Abstract.
Author URL.
Bonnington C, Gaston KJ, Evans KL (2014). Relative roles of grey squirrels, supplementary feeding, and habitat in shaping urban bird assemblages.
PLoS One,
9(10).
Abstract:
Relative roles of grey squirrels, supplementary feeding, and habitat in shaping urban bird assemblages.
Non-native species are frequently considered to influence urban assemblages. The grey squirrel Sciurus carolinensis is one such species that is widespread in the UK and is starting to spread across Europe; it predates birds' nests and can compete with birds for supplementary food. Using distance sampling across the urbanisation intensity gradient in Sheffield (UK) we test whether urban grey squirrels influence avian species richness and density through nest predation and competition for supplementary food sources. We also assess how urban bird assemblages respond to supplementary feeding. We find that grey squirrels slightly reduced the abundance of breeding bird species most sensitive to squirrel nest predation by reducing the beneficial impact of woodland cover. There was no evidence that grey squirrel presence altered relationships between supplementary feeding and avian assemblage structure. This may be because, somewhat surprisingly, supplementary feeding was not associated with the richness or density of wintering bird assemblages. These associations were positive during the summer, supporting advocacy to feed birds during the breeding season and not just winter, but explanatory capacity was limited. The amount of green space and its quality, assessed as canopy cover, had a stronger influence on avian species richness and population size than the presence of grey squirrels and supplementary feeding stations. Urban bird populations are thus more likely to benefit from investment in improving the availability of high quality habitats than controlling squirrel populations or increased investment in supplementary feeding.
Abstract.
Author URL.
Shanahan DF, Lin BB, Gaston KJ, Bush R, Fuller RA (2014). Socio-economic inequalities in access to nature on public and private lands: a case study from Brisbane, Australia.
Landscape and Urban Planning,
130(1), 14-23.
Abstract:
Socio-economic inequalities in access to nature on public and private lands: a case study from Brisbane, Australia
Opportunities to experience nature are important for human wellbeing, yet they are often inequitablydistributed across society. Socio-economic variation can explain some of this inequity, but there has beenrelatively limited consideration of how access to different kinds of nature experiences varies across society. Here we examine how tree cover (as a measure of the general 'greenness' of urban environments) andnative remnant vegetation cover (as a measure of access to higher quality natural areas) varies acrossthe socio-economic gradient within public parkland and residential yards in Brisbane, Australia. Wefound that most tree cover was provided on residential land, and spatial regression models revealed thattree cover in both public parkland and private spaces was strongly positively related to socio-economicadvantage. Conversely, most remnant vegetation cover was located on public parkland, and this wasonly weakly positively related to socio-economic status. These results suggest that municipal management of remnant vegetation can support equity in access to high quality nature experiences across thesocio-economic gradient. However, the results also highlight the important role of residential yards inproviding access to nature in general, as these areas provide the majority of overall tree cover. Thus,while public policy can enhance equity in access to nature on public lands, strategies such as social marketing and incentives that enhance nature within private spaces are important particularly within moredisadvantaged neighbourhoods. © 2014 Elsevier B.V.
Abstract.
Bonnington C, Gaston KJ, Evans KL (2014). Squirrels in suburbia: Influence of urbanisation on the occurrence and distribution of a common exotic mammal.
Urban Ecosystems,
17(2), 533-546.
Abstract:
Squirrels in suburbia: Influence of urbanisation on the occurrence and distribution of a common exotic mammal
Urbanisation is widely considered to promote the establishment of non-native species, but there is limited empirical evidence of the ecological factors driving their responses. The grey squirrel Sciurus carolinensis (Gmelin 1788) is native to North America, but is widespread in the UK and is starting to spread across Europe. It is regarded as one of the world's worst invasive animals due to its adverse impacts on native biodiversity. We use the non-native grey squirrel population in Sheffield (UK) as a case study to assess which factors limit its distribution and abundance in urban environments. In 2010 the city-wide population of adult squirrels peaked at an estimated 6539 in autumn (0.46 squirrels/ha), with maximum local densities of 8.29/ha. These densities appear to be slightly lower than those recorded in urban environments in the species' native range. Grey squirrels occurred more frequently at urban sites with larger amounts of green-space in the surrounding region. Local habitat characteristics were, however, more powerful predictors of urban grey squirrel occurrence and abundance than regional availability of green space. Canopy cover, seed bearing trees and supplementary feeders, provided for garden birds, positively influenced grey squirrels. The potential for grey squirrels to connect city dwellers with nature thus appears to be highest in urban locations that have considerable capacity to support native biodiversity. The beneficial impacts of supplementary feeding on grey squirrel populations is notable given concerns that squirrels can adversely influence bird populations. These habitat associations also imply that grey squirrels typically respond negatively to urbanisation, which challenges arguments that urbanisation favours exotic species. © 2013 Springer Science+Business Media New York.
Abstract.
Davies TW, Duffy JP, Bennie J, Gaston KJ (2014). The nature, extent, and ecological implications of marine light pollution.
Frontiers in Ecology and the Environment,
12(6), 347-355.
Abstract:
The nature, extent, and ecological implications of marine light pollution
Despite centuries of use, artificial light at night has only recently been recognized as a cause for environmental concern. Its global extent and ongoing encroachment into naturally lit ecosystems has sparked scientific interest into the many ways in which it may negatively affect human health, societal attitudes, scientific endeavors, and biological processes. Yet, perhaps because sources of artificial light are largely land based, the potential for artificial light pollution to interfere with the biology of the ocean has not been explored in any detail. There is little information on how light pollution affects those species, behaviors, and interactions that are informed by the intensity, spectra, and periodicity of natural nighttime light in marine ecosystems. Here, we provide an overview of the extent of marine light pollution, discuss how it changes the physical environment, and explore its potential role in shaping marine ecosystems. © the Ecological Society of America.
Abstract.
Edmondson JL, Davies ZG, Gaston KJ, Leake JR (2014). Urban cultivation in allotments maintains soil qualities adversely affected by conventional agriculture. Journal of Applied Ecology
Edmondson JL, O'Sullivan OS, Inger R, Potter J, McHugh N, Gaston KJ, Leake JR (2014). Urban tree effects on soil organic carbon.
PLoS One,
9(7).
Abstract:
Urban tree effects on soil organic carbon.
Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ∼75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC) and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth) compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp. but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C∶N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.
Abstract.
Author URL.
Shanahan DF, Lin BB, Gaston KJ, Bush R, Fuller RA (2014). What is the role of trees and remnant vegetation in attracting people to urban parks?. Landscape Ecology
Dallimer M, Davies ZG, Irvine KN, Maltby L, Warren PH, Gaston KJ, Armsworth PR (2014). What personal and environmental factors determine frequency of urban greenspace use?.
Int J Environ Res Public Health,
11(8), 7977-7992.
Abstract:
What personal and environmental factors determine frequency of urban greenspace use?
For many people, urban greenspaces are the only places where they encounter the natural world. This is concerning as there is growing evidence demonstrating that human well-being is enhanced by exposure to nature. There is, therefore, a compelling argument to increase how frequently people use urban greenspaces. This may be achieved in two complementary ways by encouraging: (I) non-users to start visiting urban greenspaces; (II) existing users to visit more often. Here we examine the factors that influence frequency of greenspace visitation in the city of Sheffield, England. We demonstrate that people who visit a site least frequently state lower self-reported psychological well-being. We hypothesised that a combination of socio-demographic characteristics of the participants, and the biophysical attributes of the greenspaces that they were visiting, would be important in influencing visit frequency. However, socio-demographic characteristics (income, age, gender) were not found to be predictors. In contrast, some biophysical attributes of greenspaces were significantly related to use frequency. Frequent use was more likely when the time taken to reach a greenspace was shorter and for sites with a higher index of greenspace neglect, but were unrelated to tree cover or bird species richness. We related these results to the motivations that people provide for their visits. Infrequent users were more likely to state motivations associated with the quality of the space, while frequent users gave motivations pertaining to physical, repeated activities. This suggests that there may be no simple way to manage greenspaces to maximise their use across user cohorts as the motivations for visits are very different.
Abstract.
Author URL.
Soga M, Yamaura Y, Koike S, Gaston KJ (2014). Woodland remnants as an urban wildlife refuge: a cross-taxonomic assessment.
Biodiversity and Conservation,
23(3), 649-659.
Abstract:
Woodland remnants as an urban wildlife refuge: a cross-taxonomic assessment
Urban nature is crucial for the quality of human life both within cities and beyond. In many developed cities, the numbers of restoration-through-revegetation projects have rapidly increased over the decades. However, the extent to which revegetated habitats perform compensatory roles for remnant habitats is poorly understood. We compared butterfly and ground beetle assemblages among three park types (five remnant parks, four newly established parks and five old established parks) and seven built-up sites in Tokyo, central Japan. Butterflies were classified into woodland or open-land and into patch-dependent or matrix-dwelling species. For both taxa, remnant parks and built-up sites had the highest and lowest species richness and abundance, respectively. Although the richness and abundance of open-land and matrix-dwelling butterflies did not differ among the three park types, those of woodland and patch-dependent species were significantly highest in remnant parks. In short, after 50 years, established parks did not attain the same insect assemblages as those in remnant parks. These results illustrate that whist revegetation is an effective and fast-acting conservation measure for generalist species (i.e. widely distributed species), this value is limited for specialists. In highly urbanised landscapes, therefore, even small remnant woodlands provide important refuges for urban wildlife. Remnant protection programs at the early stage of city development would decide the fate of urban biodiversity. © 2014 Springer Science+Business Media Dordrecht.
Abstract.
Davies TW, Bennie J, Inger R, Gaston KJ (2013). Artificial light alters natural regimes of night-time sky brightness.
Sci Rep,
3Abstract:
Artificial light alters natural regimes of night-time sky brightness.
Artificial light is globally one of the most widely distributed forms of anthropogenic pollution. However, while both the nature and ecological effects of direct artificial lighting are increasingly well documented, those of artificial sky glow have received little attention. We investigated how city lights alter natural regimes of lunar sky brightness using a novel ten month time series of measurements recorded across a gradient of increasing light pollution. In the city, artificial lights increased sky brightness to levels six times above those recorded in rural locations, nine and twenty kilometers away. Artificial lighting masked natural monthly and seasonal regimes of lunar sky brightness in the city, and increased the number and annual regime of full moon equivalent hours available to organisms during the night. The changes have potentially profound ecological consequences.
Abstract.
Author URL.
Davies TW, Bennie J, Inger R, de Ibarra NH, Gaston KJ (2013). Artificial light pollution: are shifting spectral signatures changing the balance of species interactions?.
Glob Chang Biol,
19(5), 1417-1423.
Abstract:
Artificial light pollution: are shifting spectral signatures changing the balance of species interactions?
Technological developments in municipal lighting are altering the spectral characteristics of artificially lit habitats. Little is yet known of the biological consequences of such changes, although a variety of animal behaviours are dependent on detecting the spectral signature of light reflected from objects. Using previously published wavelengths of peak visual pigment absorbance, we compared how four alternative street lamp technologies affect the visual abilities of 213 species of arachnid, insect, bird, reptile and mammal by producing different wavelength ranges of light to which they are visually sensitive. The proportion of the visually detectable region of the light spectrum emitted by each lamp was compared to provide an indication of how different technologies are likely to facilitate visually guided behaviours such as detecting objects in the environment. Compared to narrow spectrum lamps, broad spectrum technologies enable animals to detect objects that reflect light over more of the spectrum to which they are sensitive and, importantly, create greater disparities in this ability between major taxonomic groups. The introduction of broad spectrum street lamps could therefore alter the balance of species interactions in the artificially lit environment.
Abstract.
Author URL.
Mueller JC, Partecke J, Hatchwell BJ, Gaston KJ, Evans KL (2013). Candidate gene polymorphisms for behavioural adaptations during urbanization in blackbirds.
Molecular Ecology,
22(13), 3629-3637.
Abstract:
Candidate gene polymorphisms for behavioural adaptations during urbanization in blackbirds
Successful urban colonization by formerly rural species represents an ideal situation in which to study adaptation to novel environments. We address this issue using candidate genes for behavioural traits that are expected to play a role in such colonization events. We identified and genotyped 16 polymorphisms in candidate genes for circadian rhythms, harm avoidance and migratory and exploratory behaviour in 12 paired urban and rural populations of the blackbird Turdus merula across the Western Palaearctic. An exonic microsatellite in the SERT gene, a candidate gene for harm avoidance behaviour, exhibited a highly significant association with habitat type in an analysis conducted across all populations. Genetic divergence at this locus was consistent in 10 of the 12 population pairs; this contrasts with previously reported stochastic genetic divergence between these populations at random markers. Our results indicate that behavioural traits related to harm avoidance and associated with the SERT polymorphism experience selection pressures during most blackbird urbanization events. These events thus appear to be influenced by homogeneous adaptive processes in addition to previously reported demographic founder events. © 2013 John Wiley & Sons Ltd.
Abstract.
Mueller JC, Partecke J, Hatchwell BJ, Gaston KJ, Evans KL (2013). Candidate gene polymorphisms for behavioural adaptations during urbanization in blackbirds. Molecular Ecology
Fishburn IS, Boyer AG, Kareiva P, Gaston KJ, Armsworth PR (2013). Changing spatial patterns of conservation investment by a major land trust.
Biological Conservation,
161, 223-229.
Abstract:
Changing spatial patterns of conservation investment by a major land trust
While numerous scientific publications have used biological data and sometimes decision theory to identify where conservation funds should be invested, studies that examine where money for conservation actually has been spent and how investment patterns have changed through time are scarce. We analyze changing spatial patterns of spending on land protection, using investments by a major conservation organization, the Nature Conservancy (TNC), in the conterminous United States as a case study. We focus on investments in land protection made by TNC in four decades (1970-2009) using fee simple and easement acquisitions. During this period, TNC expanded and accelerated its investments in land conservation. We compare patterns of conservation investment in different states via two metrics: (1) the amount TNC spent to acquire land for protection, and (2) the overall area protected. The two metrics, while correlated, reveal different information about TNC's investment patterns. The amount of conservation activity TNC undertook in different states shows pronounced variation when measured either by the overall area protected or the cost of acquiring that area. We used a regression approach to relate variation in investment levels across states in each decade to a suite of biological and socioeconomic factors relevant to the effectiveness of conservation resource allocation decisions. Through time, these variables are able to explain greater spatial variation in the levels of investment into different states. The richness of native species per state showed the strongest association with overall investment levels. However, land costs also influenced investment patterns in recent decades but in ways that differed when measured by the overall area protected and by the money spent to protect it. © 2013 Elsevier Ltd.
Abstract.
Lennox GD, Gaston KJ, Acs S, Dallimer M, Hanley N, Armsworth PR (2013). Conservation when landowners have bargaining power: Continuous conservation investments and cost uncertainty.
Ecological Economics,
93, 69-78.
Abstract:
Conservation when landowners have bargaining power: Continuous conservation investments and cost uncertainty
Spatially heterogeneous costs of securing conservation agreements should be accounted for when prioritizing properties for conservation investment. Most researchers incorporating conservation costs into analyses have relied on estimates of landowners' opportunity costs of accepting a conservation agreement. Implicitly assumed in such studies is therefore that those who "produce" biodiversity (landowners) receive none of the surplus available from trade. Instead, landowners could use their bargaining power to gain profits from conservation investments. We employ game theory to determine the surplus landowners could obtain in negotiations over conservation agreements, and the consequent effects on conservation outcomes, when enrolment decisions are governed by continuous variables (e.g. the proportion of a property to enrol). In addition, we consider how landowner uncertainty regarding the opportunity costs of other landowners affects these outcomes. Landowners' ability to gain surplus is highly variable and reflects variation in the substitutability of different properties for achieving a specified conservation objective. The ability of landowners to obtain profits from conservation agreements results in conservation outcomes that are substantially diminished relative to when landowners accept investment at opportunity costs. Uncertainty increases landowner profits, leading to a greater diminution in conservation benefits. © 2013 Elsevier B.V.
Abstract.
Bonnington C, Gaston KJ, Evans KL (2013). Fearing the feline: Domestic cats reduce avian fecundity through trait-mediated indirect effects that increase nest predation by other species.
Journal of Applied Ecology,
50(1), 15-24.
Abstract:
Fearing the feline: Domestic cats reduce avian fecundity through trait-mediated indirect effects that increase nest predation by other species
Urban areas contain high densities of non-native species, which in the UK include the domestic cat Felis catus (Linnaeus 1758) and the grey squirrel Sciurus carolinensis (Gmelin 1788). The direct predation effects of domestic cats on prey populations attract intense debate, and such influences of the nest-predatory grey squirrel are receiving increasing attention. In contrast, theory predicts that sublethal and indirect effects are more important, but empirical evidence is currently lacking. We conducted controlled model presentation experiments at active urban blackbird Turdus merula (Linnaeus 1758) nests to provide the first empirical evidence that quantifies the potential sublethal and indirect effects of predators (domestic cat and grey squirrel) on avian reproductive success. Domestic cat models reduced subsequent parental provisioning rates, a strong indicator of sublethal effects, by one-third relative to a nonpredatory rabbit Oryctolagus cuniculus (Linnaeus 1758) control. There was no compensatory increase in food load size. Previous experiments demonstrate that this magnitude of reduced food delivery will reduce nestling growth rates by c. 40%. The grey squirrel model induced similar but weaker effects. Following the brief presence of the domestic cat model, subsequent daily nest predation rates, chiefly by corvids, increased by an order of magnitude relative to the squirrel and rabbit models. The intensity of parental nest defence elicited in response to model presentations predicts the probability of such third-party predator predation events, and the domestic cat model generated significant increases in nest defence behaviour. Synthesis and applications. The brief presence of a domestic cat at avian nest sites reduces subsequent provisioning rates and induces lethal trait-mediated indirect effects. We provide the first robust evidence for these latter effects in any avian predator-prey system, although they are likely to be common in many avian assemblages with high predator densities. It is imperative that future assessments of the impact of predatory species on avian prey species take lethal trait-mediated indirect effects into account, as so doing will prevent biased estimates of predator effects and facilitate the design of more effective control strategies. Full mitigation of the sublethal and indirect effects of domestic cats would problematically require permanent indoor housing. The brief presence of a domestic cat at avian nest sites reduces subsequent provisioning rates and induces lethal trait-mediated indirect effects. We provide the first robust evidence for these latter effects in any avian predator-prey system, although they are likely to be common in many avian assemblages with high predator densities. It is imperative that future assessments of the impact of predatory species on avian prey species take lethal trait-mediated indirect effects into account, as so doing will prevent biased estimates of predator effects and facilitate the design of more effective control strategies. Full mitigation of the sublethal and indirect effects of domestic cats would problematically require permanent indoor housing. © 2013 British Ecological Society.
Abstract.
Durán AP, Rauch J, Gaston KJ (2013). Global spatial coincidence between protected areas and metal mining activities.
Biological Conservation,
160, 272-278.
Abstract:
Global spatial coincidence between protected areas and metal mining activities
The global protected area (PA) system has a key role to play in biological conservation, and it is thus vital to understand the factors that are likely to limit this potential. Attention to date has focused foremost on the consequences of biases in the spatial distribution of PAs for their effectiveness and efficiency in representing biodiversity. What is less clear is the extent to which these biases may also have affected the likelihood with which PAs coincide with or are influenced by particular kinds of threatening processes, further undermining their role. An obvious candidate for such concerns is metal mining activities. Here we demonstrate that approximately 7% of mines for four key metals directly overlap with PAs and a further 27% lie within 10. km of a PA boundary. Moreover, those PAs with mining activity within their boundaries constitute around 6% of the total areal coverage of the global terrestrial PA system, and those with mining activity within or up to 10. km from their boundary constitute nearly 14% of the total area. Given the distances over which mining activities can have influences, the persistence of their effects (often long after actual operations have closed down), and the rapidly growing demand for metals, there is an urgent need to limit or mitigate such conflicts. © 2013 Elsevier Ltd.
Abstract.
Davies ZG, Dallimer M, Edmondson JL, Leake JR, Gaston KJ (2013). Identifying potential sources of variability between vegetation carbon storage estimates for urban areas.
Environmental Pollution,
183, 133-142.
Abstract:
Identifying potential sources of variability between vegetation carbon storage estimates for urban areas
Although urbanisation is a major cause of land-use change worldwide, towns and cities remain relatively understudied ecosystems. Research into urban ecosystem service provision is still an emerging field, yet evidence is accumulating rapidly to suggest that the biological carbon stores in cities are more substantial than previously assumed. However, as more vegetation carbon densities are derived, substantial variability between these estimates is becoming apparent. Here, we review procedural differences evident in the literature, which may be drivers of variation in carbon storage assessments. Additionally, we quantify the impact that some of these different approaches may have when extrapolating carbon figures derived from surveys up to a city-wide scale. To understand how/why carbon stocks vary within and between cities, researchers need to use more uniform methods to estimate stores and relate this quantitatively to standardised ‘urbanisation’ metrics, in order to facilitate comparisons.
Abstract.
Davies ZG, Dallimer M, Edmondson JL, Leake JR, Gaston KJ (2013). Identifying potential sources of variability between vegetation carbon storage estimates for urban areas.
Environmental pollution (Barking, Essex : 1987),
183, 133-142.
Abstract:
Identifying potential sources of variability between vegetation carbon storage estimates for urban areas.
Although urbanisation is a major cause of land-use change worldwide, towns and cities remain relatively understudied ecosystems. Research into urban ecosystem service provision is still an emerging field, yet evidence is accumulating rapidly to suggest that the biological carbon stores in cities are more substantial than previously assumed. However, as more vegetation carbon densities are derived, substantial variability between these estimates is becoming apparent. Here, we review procedural differences evident in the literature, which may be drivers of variation in carbon storage assessments. Additionally, we quantify the impact that some of these different approaches may have when extrapolating carbon figures derived from surveys up to a city-wide scale. To understand how/why carbon stocks vary within and between cities, researchers need to use more uniform methods to estimate stores and relate this quantitatively to standardised 'urbanisation' metrics, in order to facilitate comparisons. Copyright © 2013 Elsevier Ltd. All rights reserved.
Abstract.
Anderson K, Gaston KJ (2013). Lightweight unmanned aerial vehicles will revolutionize spatial ecology.
Frontiers in Ecology and the Environment,
11(3), 138-146.
Abstract:
Lightweight unmanned aerial vehicles will revolutionize spatial ecology
Ecologists require spatially explicit data to relate structure to function. To date, heavy reliance has been placed on obtaining such data from remote-sensing instruments mounted on spacecraft or manned aircraft, although the spatial and temporal resolutions of the data are often not suited to local-scale ecological investigations. Recent technological innovations have led to an upsurge in the availability of unmanned aerial vehicles (UAVs) - aircraft remotely operated from the ground - and there are now many lightweight UAVs on offer at reasonable costs. Flying low and slow, UAVs offer ecologists new opportunities for scale-appropriate measurements of ecological phenomena. Equipped with capable sensors, UAVs can deliver fine spatial resolution data at temporal resolutions defined by the end user. Recent innovations in UAV platform design have been accompanied by improvements in navigation and the miniaturization of measurement technologies, allowing the study of individual organisms and their spatiotemporal dynamics at close range. © the Ecological Society of America.
Abstract.
Gaston KJ, Ávila-Jiménez ML, Edmondson JL (2013). Managing urban ecosystems for goods and services.
Journal of Applied Ecology,
50(4), 830-840.
Abstract:
Managing urban ecosystems for goods and services
Concomitant with the rise in the proportion of the global human population that resides in urban areas has been growth in awareness of the importance of the provision of ecosystem goods and services to those people. Urban areas are themselves of significance in this regard because of their areal extent, and hence the quantity of services falling within their bounds, and because of the need for local provision of services to urban residents. Here, we review key challenges to the effective management of ecosystem goods and services within urban areas. These challenges include the structure of green space, its temporal dynamics, spatial constraint on ecosystem service flows, occurrence of novel forms of flows, large numbers of land managers, conflicting management goals, possible differences between perceptions of urban dwellers and the reality of the distribution and flow of ecosystem services, and the 'wicked' nature of the problem of ecosystem service management. Synthesis and applications. Urban areas present very particular combinations of challenges and opportunities for the management of ecosystem goods and services. The spatial and temporal heterogeneity of green spaces greatly complicates the maintenance and improvement in service provision as well as dramatically inflating costs. Spatial constraints on ecosystem service flows mean that these can be highly dependent on the maintenance of particular areas of connectivity, but also that provision of additional key points of connectivity may be disproportionately beneficial to those flows. The existence of novel forms of flows of ecosystem services in urban areas offers means of overcoming spatial constraints on more natural flows, but will require the development of new kinds of ecosystem process models to inform their design and management. The large numbers of land managers, conflicts between the best approaches for managing for different goods and services, and frequent differences between the perceptions of urban dwellers and the reality of urban landscapes create a complex management context. The management of ecosystem goods and services is closely allied to the challenges of conventional urban planning. However, applied ecology has a broad range of tools available to assist in determining solutions, including the use of high-resolution remote sensing techniques, landscape ecology principles and theory (e.g. patch and matrix frameworks, meta-population models), and systematic conservation planning approaches. Urban areas present very particular combinations of challenges and opportunities for the management of ecosystem goods and services. The spatial and temporal heterogeneity of green spaces greatly complicates the maintenance and improvement in service provision as well as dramatically inflating costs. Spatial constraints on ecosystem service flows mean that these can be highly dependent on the maintenance of particular areas of connectivity, but also that provision of additional key points of connectivity may be disproportionately beneficial to those flows. The existence of novel forms of flows of ecosystem services in urban areas offers means of overcoming spatial constraints on more natural flows, but will require the development of new kinds of ecosystem process models to inform their design and management. The large numbers of land managers, conflicts between the best approaches for managing for different goods and services, and frequent differences between the perceptions of urban dwellers and the reality of urban landscapes create a complex management context. The management of ecosystem goods and services is closely allied to the challenges of conventional urban planning. However, applied ecology has a broad range of tools available to assist in determining solutions, including the use of high-resolution remote sensing techniques, landscape ecology principles and theory (e.g. patch and matrix frameworks, meta-population models), and systematic conservation planning approaches. © 2013 British Ecological Society.
Abstract.
Dornelas M, Magurran AE, Buckland ST, Chao A, Chazdon RL, Colwell RK, Curtis T, Gaston KJ, Gotelli NJ, Kosnik MA, et al (2013). Quantifying temporal change in biodiversity: challenges and opportunities.
Proc Biol Sci,
280(1750).
Abstract:
Quantifying temporal change in biodiversity: challenges and opportunities.
Growing concern about biodiversity loss underscores the need to quantify and understand temporal change. Here, we review the opportunities presented by biodiversity time series, and address three related issues: (i) recognizing the characteristics of temporal data; (ii) selecting appropriate statistical procedures for analysing temporal data; and (iii) inferring and forecasting biodiversity change. With regard to the first issue, we draw attention to defining characteristics of biodiversity time series--lack of physical boundaries, uni-dimensionality, autocorrelation and directionality--that inform the choice of analytic methods. Second, we explore methods of quantifying change in biodiversity at different timescales, noting that autocorrelation can be viewed as a feature that sheds light on the underlying structure of temporal change. Finally, we address the transition from inferring to forecasting biodiversity change, highlighting potential pitfalls associated with phase-shifts and novel conditions.
Abstract.
Author URL.
Dornelas M, Magurran AE, Buckland ST, Chao A, Chazdon RL, Colwell RK, Curtis T, Gaston KJ, Gotelli NJ, Kosnik MA, et al (2013). Quantifying temporal change in biodiversity: challenges and opportunities.
Proceedings. Biological sciences / the Royal Society,
280(1750).
Abstract:
Quantifying temporal change in biodiversity: challenges and opportunities.
Growing concern about biodiversity loss underscores the need to quantify and understand temporal change. Here, we review the opportunities presented by biodiversity time series, and address three related issues: (i) recognizing the characteristics of temporal data; (ii) selecting appropriate statistical procedures for analysing temporal data; and (iii) inferring and forecasting biodiversity change. With regard to the first issue, we draw attention to defining characteristics of biodiversity time series--lack of physical boundaries, uni-dimensionality, autocorrelation and directionality--that inform the choice of analytic methods. Second, we explore methods of quantifying change in biodiversity at different timescales, noting that autocorrelation can be viewed as a feature that sheds light on the underlying structure of temporal change. Finally, we address the transition from inferring to forecasting biodiversity change, highlighting potential pitfalls associated with phase-shifts and novel conditions.
Abstract.
Gaston KJ, Avila-Jimenez ML, Edmondson JL (2013). REVIEW: Managing urban ecosystems for goods and services.
JOURNAL OF APPLIED ECOLOGY,
50(4), 830-840.
Author URL.
Thomas CD, Anderson BJ, Moilanen A, Eigenbrod F, Heinemeyer A, Quaife T, Roy DB, Gillings S, Armsworth PR, Gaston KJ, et al (2013). Reconciling biodiversity and carbon conservation.
Ecology Letters,
16(SUPPL.1), 39-47.
Abstract:
Reconciling biodiversity and carbon conservation
Climate change is leading to the development of land-based mitigation and adaptation strategies that are likely to have substantial impacts on global biodiversity. of these, approaches to maintain carbon within existing natural ecosystems could have particularly large benefits for biodiversity. However, the geographical distributions of terrestrial carbon stocks and biodiversity differ. Using conservation planning analyses for the New World and Britain, we conclude that a carbon-only strategy would not be effective at conserving biodiversity, as have previous studies. Nonetheless, we find that a combined carbon-biodiversity strategy could simultaneously protect 90% of carbon stocks (relative to a carbon-only conservation strategy) and > 90% of the biodiversity (relative to a biodiversity-only strategy) in both regions. This combined approach encapsulates the principle of complementarity, whereby locations that contain different sets of species are prioritised, and hence disproportionately safeguard localised species that are not protected effectively by carbon-only strategies. It is efficient because localised species are concentrated into small parts of the terrestrial land surface, whereas carbon is somewhat more evenly distributed; and carbon stocks protected in one location are equivalent to those protected elsewhere. Efficient compromises can only be achieved when biodiversity and carbon are incorporated together within a spatial planning process. © 2012 John Wiley & Sons Ltd/CNRS.
Abstract.
Durán AP, Casalegno S, Marquet PA, Gaston KJ (2013). Representation of ecosystem services by terrestrial protected areas: Chile as a case study.
PLoS One,
8(12).
Abstract:
Representation of ecosystem services by terrestrial protected areas: Chile as a case study.
Protected areas are increasingly considered to play a key role in the global maintenance of ecosystem processes and the ecosystem services they provide. It is thus vital to assess the extent to which existing protected area systems represent those services. Here, for the first time, we document the effectiveness of the current Chilean protected area system and its planned extensions in representing both ecosystem services (plant productivity, carbon storage and agricultural production) and biodiversity. Additionally, we evaluate the effectiveness of protected areas based on their respective management objectives. Our results show that existing protected areas in Chile do not contain an unusually high proportion of carbon storage (14.9%), agricultural production (0.2%) or biodiversity (11.8%), and also represent a low level of plant productivity (Normalized Difference Vegetation Index of 0.38). Proposed additional priority sites enhance the representation of ecosystem services and biodiversity, but not sufficiently to attain levels of representation higher than would be expected for their area of coverage. Moreover, when the species groups were assessed separately, amphibians was the only one well represented. Suggested priority sites for biodiversity conservation, without formal protection yet, was the only protected area category that over-represents carbon storage, agricultural production and biodiversity. The low representation of ecosystem services and species' distribution ranges by the current protected area system is because these protected areas are heavily biased toward southern Chile, and contain large extents of ice and bare rock. The designation and management of proposed priority sites needs to be addressed in order to increase the representation of ecosystem services within the Chilean protected area system.
Abstract.
Author URL.
Casalegno S, Inger R, Desilvey C, Gaston KJ (2013). Spatial covariance between aesthetic value & other ecosystem services.
PLoS One,
8(6).
Abstract:
Spatial covariance between aesthetic value & other ecosystem services.
Mapping the spatial distribution of ecosystem goods and services represents a burgeoning field of research, although how different services covary with one another remains poorly understood. This is particularly true for the covariation of supporting, provisioning and regulating services with cultural services (the non-material benefits people gain from nature). This is largely because of challenges associated with the spatially specific quantification of cultural ecosystem services. We propose an innovative approach for evaluating a cultural service, the perceived aesthetic value of ecosystems, by quantifying geo-tagged digital photographs uploaded to social media resources. Our analysis proceeds from the premise that images will be captured by greater numbers of people in areas that are more highly valued for their aesthetic attributes. This approach was applied in Cornwall, UK, to carry out a spatial analysis of the covariation between ecosystem services: soil carbon stocks, agricultural production, and aesthetic value. Our findings suggest that online geo-tagged images provide an effective metric for mapping a key component of cultural ecosystem services. They also highlight the non-stationarity in the spatial relationships between patterns of ecosystem services.
Abstract.
Author URL.
Cantú-Salazar L, Gaston KJ (2013). Species richness and representation in protected areas of the Western hemisphere: Discrepancies between checklists and range maps.
Diversity and Distributions,
19(7), 782-793.
Abstract:
Species richness and representation in protected areas of the Western hemisphere: Discrepancies between checklists and range maps
Aim: We use data based on species checklists and geographical range maps for 3096 amphibian, 4100 bird and 1878 terrestrial mammal species to explore possible discrepancies in estimates of species richness for protected areas. We predict substantial differences between checklist and range map richness for smaller areas, where higher errors of commission from range maps are likely to occur. We also explore how discrepancies between species inventories and range maps may affect assessments of reserve prioritization and representation. Location: Continental America and associated islands. Methods: We obtained species numbers based on checklists for 619 protected areas from a variety of sources, including management plans, technical reports, environmental assessments, official websites, biodiversity databases and conservation agencies, and evaluated how these correlate with species richness estimates from geographical range map databases, also testing for an effect of reserve size on range map omission and commission errors. Results: Species richness estimates obtained from checklists and range maps showed a significant positive relationship for all three groups of vertebrates, although for most protected areas, estimates of richness from range overlap maps tended to be overestimates, especially for amphibians and mammals in species-rich regions. Protected area size explained little of the discrepancies between checklist and range map richness. Species representation in protected areas based on checklists was in general lower than representation based on range maps. Main conclusions: Our results suggest that range maps, although far from perfect, have the advantage of reducing geographical biases and filling gaps that exist in point locality data at least in species-rich protected areas, while most available checklists in these regions were extremely variable in quality and availability, lacking of basic information on survey design, reliability and completeness. However, range maps will likely overestimate species representation in protected areas and should thus be treated with caution in this context. © 2013 John Wiley & Sons Ltd.
Abstract.
Rouquette JR, Dallimer M, Armsworth PR, Gaston KJ, Maltby L, Warren PH (2013). Species turnover and geographic distance in an urban river network.
Diversity and Distributions,
19(11), 1429-1439.
Abstract:
Species turnover and geographic distance in an urban river network
Aim: Understanding the relationships between species turnover, environmental features and the geographic distance between sites can provide important insights into the processes driving species diversity. This is particularly relevant where the effective distance between sites may be a function of the habitat or topographic features of the landscape and the means of dispersal of the organism. River networks, in particular in human-modified landscapes, are a striking example of such a situation. Here, we use data for both aquatic and terrestrial organisms across an urban river network to examine patterns of species turnover and to determine whether these patterns differ between different taxonomic groups. Location: Sheffield area, UK. Methods: Aquatic (macroinvertebrates, diatoms) and terrestrial (birds, plants, butterflies) organisms were surveyed at 41 sites across an urban river network. We assessed the relationship between turnover and three alternative geographic distance measures (Euclidean, network and flow distance), whilst also taking into account the environmental distance between sites, using Mantel and partial Mantel tests. Results: Turnover of all taxonomic groups apart from butterflies was significantly correlated with at least one measure of geographic distance. The aquatic taxonomic groups showed the strongest correlations with the geographic distance measures, and in particular with network distance. Terrestrial taxa were more closely associated with environmental than any of the geographic distance measures, although network distance remained significant for birds and some plant groups after removing the effect of environmental distance. Water-dispersed and neophyte plant groups were significantly related to network and flow distance. Main conclusions: the results suggest that aquatic communities are strongly influenced by spatial processes occurring within the river network. Terrestrial taxa have a more complex relationship with distance, with different components of these communities displaying different responses. Nevertheless, it is clear that connectivity along the river corridor is important for both aquatic and terrestrial communities. © 2013 John Wiley & Sons Ltd.
Abstract.
Gaston KJ (2013). Sustainability: a green light for efficiency.
Nature,
497(7451), 560-561.
Author URL.
Gaston KJ, Bennie J, Davies TW, Hopkins J (2013). The ecological impacts of nighttime light pollution: a mechanistic appraisal.
Biological Reviews,
88(4), 912-927.
Abstract:
The ecological impacts of nighttime light pollution: a mechanistic appraisal
The ecological impacts of nighttime light pollution have been a longstanding source of concern, accentuated by realized and projected growth in electrical lighting. As human communities and lighting technologies develop, artificial light increasingly modifies natural light regimes by encroaching on dark refuges in space, in time, and across wavelengths. A wide variety of ecological implications of artificial light have been identified. However, the primary research to date is largely focused on the disruptive influence of nighttime light on higher vertebrates, and while comprehensive reviews have been compiled along taxonomic lines and within specific research domains, the subject is in need of synthesis within a common mechanistic framework. Here we propose such a framework that focuses on the cross-factoring of the ways in which artificial lighting alters natural light regimes (spatially, temporally, and spectrally), and the ways in which light influences biological systems, particularly the distinction between light as a resource and light as an information source. We review the evidence for each of the combinations of this cross-factoring. As artificial lighting alters natural patterns of light in space, time and across wavelengths, natural patterns of resource use and information flows may be disrupted, with downstream effects to the structure and function of ecosystems. This review highlights: (i) the potential influence of nighttime lighting at all levels of biological organisation (from cell to ecosystem); (ii) the significant impact that even low levels of nighttime light pollution can have; and (iii) the existence of major research gaps, particularly in terms of the impacts of light at population and ecosystem levels, identification of intensity thresholds, and the spatial extent of impacts in the vicinity of artificial lights. © 2013 Cambridge Philosophical Society.
Abstract.
Cantú-Salazar L, Orme CDL, Rasmussen PC, Blackburn TM, Gaston KJ (2013). The performance of the global protected area system in capturing vertebrate geographic ranges.
Biodiversity and Conservation,
22(4), 1033-1047.
Abstract:
The performance of the global protected area system in capturing vertebrate geographic ranges
Given the heavy reliance placed on and investment in protected areas for biological conservation, there has been much debate as to how effective these are in representing biodiversity features within their boundaries. The majority of studies addressing this issue have been conducted on a regional or national basis, precluding a broad picture of patterns of representation at the species level. We present a global assessment of the representation of the terrestrial geographic ranges of complete taxonomic groups: all known extant amphibians, birds and mammals (20,736 species) within the current global system of protected areas. We conclude that it is necessary substantially to improve the levels of coverage of the geographic ranges of the majority of species, even the widespread ones. This is particularly true for rare species, which might be assumed to be foci for protected area systems. To improve on the low levels of coverage of vertebrate ranges attained by the existing areas, key regions should be targeted, but heavy reliance will also have to be placed on approaches to sustaining populations in the wider, unprotected landscape. © 2013 Springer Science+Business Media Dordrecht.
Abstract.
Irvine KN, Warber SL, Devine-Wright P, Gaston KJ (2013). Understanding Urban Green Space as a Health Resource: a Qualitative Comparison of Visit Motivation and Derived Effects among Park Users in Sheffield, UK.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH,
10(1), 417-442.
Author URL.
De Boer WF, van Langevelde F, Prins HHT, De Ruiter PC, Blanc J, Vis MJP, Gaston KJ, Hamilton ID (2013). Understanding spatial differences in African elephant densities and occurrence, a continent-wide analysis.
Biological Conservation,
159, 468-476.
Abstract:
Understanding spatial differences in African elephant densities and occurrence, a continent-wide analysis
The densities and survival of many wild animals are presently at risk. Crucial for improving conservation actions is an understanding on a large scale of the relative importance of human and ecological factors in determining the distribution and densities of species. However, even for such charismatic species as the African elephant (Loxodonta africana), spatially explicit, large-scale analyses are lacking, although various local-scale studies are available. Here we show through continent-scale analysis that ecological factors, such as food availability, are correlated with the presence of elephants, but human factors are better predictors of elephant population densities where elephants are present. These densities strongly correlate with conservation policy, literacy rate, corruption and economic welfare, and associate less with the availability of food or water for these animals. Our results suggest that conservation strategies should be organized in a socioeconomic context. The successful conservation of large animal species could depend more on good human education, greater literacy, good governance, and less corruption, than merely setting aside areas for conservation. © 2012 Elsevier Ltd.
Abstract.
Keniger LE, Gaston KJ, Irvine KN, Fuller RA (2013). What are the benefits of interacting with nature?.
International Journal of Environmental Research and Public Health,
10(3), 913-935.
Abstract:
What are the benefits of interacting with nature?
There is mounting empirical evidence that interacting with nature delivers measurable benefits to people. Reviews of this topic have generally focused on a specific type of benefit, been limited to a single discipline, or covered the benefits delivered from a particular type of interaction. Here we construct novel typologies of the settings, interactions and potential benefits of people-nature experiences, and use these to organise an assessment of the benefits of interacting with nature. We discover that evidence for the benefits of interacting with nature is geographically biased towards high latitudes and Western societies, potentially contributing to a focus on certain types of settings and benefits. Social scientists have been the most active researchers in this field. Contributions from ecologists are few in number, perhaps hindering the identification of key ecological features of the natural environment that deliver human benefits. Although many types of benefits have been studied, benefits to physical health, cognitive performance and psychological well-being have received much more attention than the social or spiritual benefits of interacting with nature, despite the potential for important consequences arising from the latter. The evidence for most benefits is correlational, and although there are several experimental studies, little as yet is known about the mechanisms that are important for delivering these benefits. For example, we do not know which characteristics of natural settings (e.g. biodiversity, level of disturbance, proximity, accessibility) are most important for triggering a beneficial interaction, and how these characteristics vary in importance among cultures, geographic regions and socio-economic groups. These are key directions for future research if we are to design landscapes that promote high quality interactions between people and nature in a rapidly urbanising world. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Abstract.
Dallimer M, Irvine KN, Skinner AMJ, Davies ZG, Rouquette JR, Maltby LL, Warren PH, Armsworth PR, Gaston KJ (2012). Biodiversity and the feel-good factor: Understanding associations between self-reported human well-being and species richness.
BioScience,
62(1), 47-55.
Abstract:
Biodiversity and the feel-good factor: Understanding associations between self-reported human well-being and species richness
Over half of the world's human population lives in cities, and for many, urban greenspaces are the only places where they encounter biodiversity. This is of particular concern because there is growing evidence that human well-being is enhanced by exposure to nature. However, the specific qualities of greenspaces that offer the greatest benefits remain poorly understood. One possibility is that humans respond positively to increased levels of biodiversity. Here, we demonstrate the lack of a consistent relationship between actual plant, butterfly, and bird species richness and the psychological well-being of urban greenspace visitors. Instead, well-being shows a positive relationship with the richness that the greenspace users perceived to be present. One plausible explanation for this discrepancy, which we investigate, is that people generally have poor biodiversity-identification skills. The apparent importance of perceived species richness and the mismatch between reality and perception pose a serious challenge for aligning conservation and human well-being agendas. © 2012 by American Institute of Biological Sciences. All rights reserved.
Abstract.
Webb TJ, Freckleton RP, Gaston KJ (2012). Characterizing abundance-occupancy relationships: There is no artefact.
Global Ecology and Biogeography,
21(9), 952-957.
Abstract:
Characterizing abundance-occupancy relationships: There is no artefact
Positive abundance-occupancy relationships (AORs) are among the most general macroecological patterns: locally common species are regionally widespread, locally rare species are regionally restricted. In a recent contribution, Wilson (Global Ecology and Biogeography, 2011, 20, 193-202) made three claims: (1) that AORs are critically dependent on the method used to calculate average abundance; (2) averaging abundance over occupied sites tends to lead to a very high incidence of negative relationships; (3) this represents a statistical artefact that should be considered in studies of AORs. Here we show that this outcome arises in Wilson's simulations purely due to an arbitrary choice of occupancy models and parameter ranges. The resulting negative relationships are not statistical artefacts, but are easily interpreted in terms of spatial aggregation in abundant species. The fact that empirical evidence fails to support a high prevalence of negative AORs suggests, however, that such parameter combinations arise only rarely in nature. We conclude that simulations that are based on untested assumptions, and that produce patterns unsupported by empirical evidence, have limited use in characterizing AORs, and add little to understanding of the processes driving important relationships between local population size and regional occupancy. © 2011 Blackwell Publishing Ltd.
Abstract.
Evans KL, Newton J, Gaston KJ, Sharp SP, McGowan A, Hatchwell BJ (2012). Colonisation of urban environments is associated with reduced migratory behaviour, facilitating divergence from ancestral populations.
Oikos,
121(4), 634-640.
Abstract:
Colonisation of urban environments is associated with reduced migratory behaviour, facilitating divergence from ancestral populations
How individuals colonising novel environments overcome the diverse suite of new selection pressures is a fundamental question in ecology and evolution. Urban environments differ markedly from the rural ones that they replace and successful colonisation of urban areas may therefore require local adaptation and phenotypic/genetic divergence from ancestral populations. Such a process would be facilitated by limited dispersal to and from the novel habitat. Here we assess divergence in migratory behaviour between seven pairs of urban and rural European blackbird Turdus merula populations along a 2800 km transect across Europe. This former forest specialist is now amongst the most abundant urban birds across most of its range. We use a stable isotope approach due to the lack of sufficient ringing data from multiple urban populations, and compare hydrogen isotopic ratios of tissues grown in the breeding (feathers) and wintering areas (claws) to derive an index of long distance migratory behaviour. We find a tendency for urban blackbirds to be more sedentary than rural ones at all sites and this divergence is particularly strong at the north-eastern limit of our transect, i.e. in Estonia and Latvia. These urban populations are those that have been established most recently (from the late 1930s to 1950s) implying that urbanisation can promote rapid ecological divergence. The increased sedentary behaviour of urban birds could promote further ecological divergence between rural and urban populations, such as the earlier breeding of urban blackbirds, and in some cases may contribute to their previously documented genetic divergence. © 2011 the Authors. Oikos © 2012 Nordic Society Oikos.
Abstract.
Dallimer M, Rouquette JR, Skinner AMJ, Armsworth PR, Maltby LM, Warren PH, Gaston KJ (2012). Contrasting patterns in species richness of birds, butterflies and plants along riparian corridors in an urban landscape.
Diversity and Distributions,
18(8), 742-753.
Abstract:
Contrasting patterns in species richness of birds, butterflies and plants along riparian corridors in an urban landscape
Aim Urbanization is a major driver of global land-use change, substantially modifying patterns of biodiversity. Managing these impacts has become a conservation priority. The creation and maintenance of greenways, such as river corridors, is frequently promoted as a strategy for mitigating habitat fragmentation in urban areas by bringing semi-natural habitat cover into city centres. However, there is little evidence to support this assertion. Here, we examine whether riparian zones maintain semi-natural habitat cover in urban areas and how species richness varies along such zones. Location Sheffield, Northern England. Methods Multiple taxonomic groups (birds, butterflies, plants) were surveyed at 105 sites spanning seven riparian corridors that transect the study system. For all groups, we model the relationships between species richness and environmental variables pertinent to an urban system. To test whether riparian zones can act to maintain semi-natural habitats within a city, we modelled the proportion of semi-natural land cover within 250m grid squares that do, and do not, contain a river. Results Species richness varied markedly in relation to distance from the urban core. Trends differed both between taxonomic groups and between rivers, reflecting the complex patterns of environmental variation associated with cities. This suggests that biodiversity surveys that focus on a single group or transect cannot reliably be used as surrogates even within the same city. Nonetheless, there were common environmental predictors of species richness. Plant, avian and butterfly richness all responded positively to Habitat Diversity and the latter two declined with increases in sealed surface. Main conclusions Multiple transects and taxonomic groups are required to describe species richness responses to urbanization as no single pattern is evident. Although riparian zones are an important component of the mosaic of urban habitats, we find that river corridors do not disproportionately support tree and Natural Surface Cover when compared to non-riverine urban areas. © 2012 Blackwell Publishing Ltd.
Abstract.
Gaston KJ (2012). Ecology: the importance of being rare. Nature, 487(7405), 46-47.
Canard E, Mouquet N, Marescot L, Gaston KJ, Gravel D, Mouillot D (2012). Emergence of structural patterns in neutral trophic networks.
PLoS ONE,
7(8).
Abstract:
Emergence of structural patterns in neutral trophic networks
Interaction networks are central elements of ecological systems and have very complex structures. Historically, much effort has focused on niche-mediated processes to explain these structures, while an emerging consensus posits that both niche and neutral mechanisms simultaneously shape many features of ecological communities. However, the study of interaction networks still lacks a comprehensive neutral theory. Here we present a neutral model of predator-prey interactions and analyze the structural characteristics of the simulated networks. We find that connectance values (complexity) and complexity-diversity relationships of neutral networks are close to those observed in empirical bipartite networks. High nestedness and low modularity values observed in neutral networks fall in the range of those from empirical antagonist bipartite networks. Our results suggest that, as an alternative to niche-mediated processes that induce incompatibility between species ("niche forbidden links"), neutral processes create "neutral forbidden links" due to uneven species abundance distributions and the low probability of interaction between rare species. Neutral trophic networks must be seen as the missing endpoint of a continuum from niche to purely stochastic approaches of community organization. © 2012 Canard et al.
Abstract.
Hanley N, Acs S, Dallimer M, Gaston KJ, Graves A, Morris J, Armsworth PR (2012). Farm-scale ecological and economic impacts of agricultural change in the uplands.
Land Use Policy,
29(3), 587-597.
Abstract:
Farm-scale ecological and economic impacts of agricultural change in the uplands
Recent decades have witnessed substantial losses of biodiversity in Europe, partly driven by the ecological changes associated with intensification of agricultural production. These changes have particularly affected avian (bird) diversity in marginal areas such as the uplands of the UK. Future trends for upland birds will likely be impacted by changes in agricultural support regimes, such as those currently envisaged in on-going reforms of the Common Agricultural Policy. We developed integrated ecological-economic models, using seven different indicators of biodiversity based on avian species richness and individual bird densities. The models represent six different types of farms which are typical for the UK uplands, and were used to assess the outcomes of different agricultural futures. Our results show that the impacts of these future agricultural scenarios on farm incomes, land use and biodiversity are very diverse across policy scenarios and farm types. Moreover, each policy scenario produces un-equal distributions of farm income changes and gains and losses in alternative biodiversity indicators. This shows that generalisations of the effects of policy and pricing changes on farm incomes, land uses and biodiversity can be misleading. Our results also suggest that a focus on umbrella species or biodiversity indicators (such as total species richness) can miss important compositional effects. © 2011 Elsevier Ltd.
Abstract.
Tang Z, Fang J, Chi X, Yang Y, Ma W, Mohhamot A, Guo Z, Liu Y, Gaston KJ (2012). Geography, Environment, and spatial turnover of species in China's grasslands.
Ecography,
35(12), 1103-1109.
Abstract:
Geography, Environment, and spatial turnover of species in China's grasslands
Environment and spatial processes are key factors in shaping species composition in a community. These two factors make competing predictions concerning the decay of species composition similarity with environmental divergence and geographic distance. Unfortunately, these can be difficult to test independently because changes in environment are commonly well correlated with geographic distance. However, an opportunity is provided by exploiting marked regional differences in the spatial structure of the environment. In this study, we test the predictions of environment filtering and dispersal in explaining species turnover using > 300 study sites spanning ̃4000 km, across three major grasslands in China in which the environment is spatially structured to different degrees. We find that species composition similarity decayed with environmental divergence in the same way in all three regions, and even across biogeographic regions between which dispersal barriers are evident; in contrast, the decay of species composition similarity with geographic distance depended largely on the spatial structure of the environment. We conclude that, at the scale of study, environmental filtering rather than spatial processes best explains patterns of species turnover in China's grasslands. © 2012 the Authors. Ecography © 2012 Nordic Society Oikos.
Abstract.
Sandel B, Arge L, Dalsgaard B, Davies RG, Gaston KJ, Sutherland WJ, Svenning J-C (2012). Global Endemism Needs Spatial Integration Response.
SCIENCE,
335(6066), 285-286.
Author URL.
Davies ZG, Fuller RA, Dallimer M, Loram A, Gaston KJ (2012). Household factors influencing participation in bird feeding activity: a national scale analysis.
PLoS ONE,
7(6).
Abstract:
Household factors influencing participation in bird feeding activity: a national scale analysis
Ameliorating pressures on the ecological condition of the wider landscape outside of protected areas is a key focus of conservation initiatives in the developed world. In highly urbanized nations, domestic gardens can play a significant role in maintaining biodiversity and facilitating human-wildlife interactions, which benefit personal and societal health and well-being. The extent to which sociodemographic and socioeconomic factors are associated with engagement in wildlife gardening activities remain largely unresolved. Using two household-level survey datasets gathered from across Britain, we determine whether and how the socioeconomic background of a household influences participation in food provision for wild birds, the most popular and widespread form of human-wildlife interaction. A majority of households feed birds (64% across rural and urban areas in England, and 53% within five British study cities). House type, household size and the age of the head of the household were all important predictors of bird feeding, whereas gross annual household income, the occupation of the head of the household, and whether the house is owned or rented were not. In both surveys, the prevalence of bird feeding rose as house type became more detached and as the age of the head of the household increased. A clear, consistent pattern between households of varying size was less evident. When regularity of food provision was examined in the study cities, just 29% of households provided food at least once a week. The proportion of households regularly feeding birds was positively related to the age of the head of the household, but declined with gross annual income. As concerns grow about the lack of engagement between people and the natural environment, such findings are important if conservation organizations are successfully to promote public participation in wildlife gardening specifically and environmentally beneficial behaviour in society more generally. © 2012 Davies et al.
Abstract.
Dallimer M, Skinner AMJ, Davies ZG, Armsworth PR, Gaston KJ (2012). Multiple habitat associations: the role of offsite habitat in determining onsite avian density and species richness.
Ecography,
35(2), 134-145.
Abstract:
Multiple habitat associations: the role of offsite habitat in determining onsite avian density and species richness
Many animal populations continue to decline despite occurring in protected areas or on sympathetically managed sites. Frequently, this is because a specific habitat patch may not fulfil all the niche requirements of a threatened species. For instance, species often move between, and make use of, multiple habitat types for breeding, roosting and feeding within the same landscape. These cross-habitat interactions present a challenge for conservation. Here we quantify how the habitat associations of individual species and assemblages occurring within two distinct but adjacent habitat types (moorland and farmland) determine a suite of density and richness indicators, using the bird community of the English uplands as a case study. There was a clear association between onsite avian density and richness and offsite habitat structure (e.g. vegetation height, percent cover of dominant plant species, land management practices). Although such effects are not universal across all species and assemblages, where present (for five farmland and three moorland indicators) the increase in explanatory power offered by including offsite habitat structure can be large. By constructing scenarios of possible changes to management practice on both moorland and farmland, we demonstrate a real conservation benefit can be obtained by altering management in offsite habitats. For example, reducing burning intensity on moorland can result in a five-fold increase in snipe Gallinago gallinago density on farmland, without an alteration in farmland habitat. For one species (Eurasian curlew Numenius arquata), we demonstrate the frequency with which birds move between and utilise farmland and moorland during the breeding season, and therefore the importance of both habitat types to maintaining population densities. The multiple habitat dependency phenomenon quantified here is common and not restricted to birds. The successful conservation of many threatened species will thus depend on coordinated cross-habitat management. © 2011 the Authors. Ecography © 2012 Nordic Society Oikos.
Abstract.
Edmondson JL, Davies ZG, McHugh N, Gaston KJ, Leake JR (2012). Organic carbon hidden in urban ecosystems.
Sci Rep,
2Abstract:
Organic carbon hidden in urban ecosystems.
Urbanization is widely presumed to degrade ecosystem services, but empirical evidence is now challenging these assumptions. We report the first city-wide organic carbon (OC) budget for vegetation and soils, including under impervious surfaces. Urban soil OC storage was significantly greater than in regional agricultural land at equivalent soil depths, however there was no significant difference in storage between soils sampled beneath urban greenspaces and impervious surfaces, at equivalent depths. For a typical U.K. city, total OC storage was 17.6
kg m(-2) across the entire urban area (assuming 0
kg m(-2) under 15% of land covered by buildings). The majority of OC (82%) was held in soils, with 13% found under impervious surfaces, and 18% stored in vegetation. We reveal that assumptions underpinning current national estimates of ecosystem OC stocks, as required by Kyoto Protocol signatories, are not robust and are likely to have seriously underestimated the contributions of urban areas.
Abstract.
Author URL.
Tang Z, Fang J, Chi X, Feng J, Liu Y, Shen Z, Wang X, Wang Z, Wu X, Zheng C, et al (2012). Patterns of plant beta-diversity along elevational and latitudinal gradients in mountain forests of China.
Ecography,
35(12), 1083-1091.
Abstract:
Patterns of plant beta-diversity along elevational and latitudinal gradients in mountain forests of China
Biodiversity patterns and their underlying mechanisms have long been focal topics of study for ecologists and biogeographers. However, compared with spatial variation in species richness (α- and γ-diversity), β-diversity, or the dissimilarity of species composition between two or more sites has until recently received limited attention. In this study, we explored the large-scale patterns of altitudinal turnover (β-diversity) of plants in montane forests of China, based on systematic inventories of 1153 plots from 46 mountains distributed over ̃30 degrees of latitude (21.9-51.7°N) and ̃4100 m of altitude (160-4250 m). The β-diversity of trees and shrubs declined significantly with increasing latitude. Along the altitudinal gradient, β-diversity of both trees and shrubs showed non-significant trends in most mountains. Differences in climate explained ̃30.0% of the variation in tree β-diversity (27.7, 36.5, and 26.2% for the Jaccard's, βj, Sorenson's, βs, and Simpson's dissimilarity, βsim, respectively), with mean annual temperature being most important, and ≤ 10.0% of that in shrub β-diversity (10.0, 8.2, and 7.0% for βj, βs, and βsim, respectively), with annual actual evapotranspiration and annual precipitation as the main predictors. However, climatic controls of β-diversity varied dramatically in different biogeograpical regions. The β-diversity of trees exhibited stronger, whereas that of shrubs showed weaker, climatic patterns in temperate and arid than subtropical regions. These results suggest that mechanisms causing patterns of β-diversity may differ between latitudinal and altitudinal gradients, and among biogeographical regions; as a result, caution should be exercised in drawing close parallels between patterns and causes of β-diversity along latitudinal and altitudinal gradients and among regions. © 2012 the Authors. Ecography © 2012 Nordic Society Oikos.
Abstract.
Gaston KJ, Davies TW, Bennie J, Hopkins J (2012). Reducing the ecological consequences of night-time light pollution: options and developments.
J Appl Ecol,
49(6), 1256-1266.
Abstract:
Reducing the ecological consequences of night-time light pollution: options and developments.
1. Much concern has been expressed about the ecological consequences of night-time light pollution. This concern is most often focused on the encroachment of artificial light into previously unlit areas of the night-time environment, but changes in the spectral composition, duration and spatial pattern of light are also recognized as having ecological effects.2. Here, we examine the potential consequences for organisms of five management options to reduce night-time light pollution. These are to (i) prevent areas from being artificially lit; (ii) limit the duration of lighting; (iii) reduce the 'trespass' of lighting into areas that are not intended to be lit (including the night sky); (iv) change the intensity of lighting; and (v) change the spectral composition of lighting.3. Maintaining and increasing natural unlit areas is likely to be the most effective option for reducing the ecological effects of lighting. However, this will often conflict with other social and economic objectives. Decreasing the duration of lighting will reduce energy costs and carbon emissions, but is unlikely to alleviate many impacts on nocturnal and crepuscular animals, as peak times of demand for lighting frequently coincide with those in the activities of these species. Reducing the trespass of lighting will maintain heterogeneity even in otherwise well-lit areas, providing dark refuges that mobile animals can exploit. Decreasing the intensity of lighting will reduce energy consumption and limit both skyglow and the area impacted by high-intensity direct light. Shifts towards 'whiter' light are likely to increase the potential range of environmental impacts as light is emitted across a broader range of wavelengths.4.Synthesis and applications. The artificial lightscape will change considerably over coming decades with the drive for more cost-effective low-carbon street lighting solutions and growth in the artificially lit area. Developing lighting strategies that minimize adverse ecological impacts while balancing the often conflicting requirements of light for human utility, comfort and safety, aesthetic concerns, energy consumption and carbon emission reduction constitute significant future challenges. However, as both lighting technology and understanding of its ecological effects develop, there is potential to identify adaptive solutions that resolve these conflicts.
Abstract.
Author URL.
Sandel B, Arge L, Dalsgaard B, Davies RG, Gaston KJ, Sutherland WJ, Svenning JC (2012). Response - Global endemism needs spatial integration. Science, 335(6066), 285-286.
Davies TW, Bennie J, Gaston KJ (2012). Street lighting changes the composition of invertebrate communities.
Biol Lett,
8(5), 764-767.
Abstract:
Street lighting changes the composition of invertebrate communities.
Artificial lighting has been used to illuminate the nocturnal environment for centuries and continues to expand with urbanization and economic development. Yet, the potential ecological impact of the resultant light pollution has only recently emerged as a major cause for concern. While investigations have demonstrated that artificial lighting can influence organism behaviour, reproductive success and survivorship, none have addressed whether it is altering the composition of communities. We show, for the first time, that invertebrate community composition is affected by proximity to street lighting independently of the time of day. Five major invertebrate groups contributed to compositional differences, resulting in an increase in the number of predatory and scavenging individuals in brightly lit communities. Our results indicate that street lighting changes the environment at higher levels of biological organization than previously recognized, raising the potential that it can alter the structure and function of ecosystems.
Abstract.
Author URL.
Braschler B, Chown SL, Gaston KJ (2012). The Fynbos and Succulent Karoo biomes do not have exceptional local ant richness.
PLoS ONE,
7(3).
Abstract:
The Fynbos and Succulent Karoo biomes do not have exceptional local ant richness
Background: the Fynbos (FB) and Succulent Karoo biomes (SKB) have high regional plant diversity despite relatively low productivity. Local diversity in the region varies but is moderate. For insects, previous work suggests that strict phytophages, but not other taxa, may have high regional richness. However, what has yet to be investigated is whether the local insect species richness of FB and SKB is unusual for a region of this productivity level at this latitude, and whether regional richness is also high. Here we determine whether this is the case for ants. Methodology/Principal Findings: We use species richness data from pitfall traps in the FB and SKB in the Western Cape Province, South Africa and a global dataset of local ant richness extracted from the literature. We then relate the globally derived values of local richness to two energy-related predictors-productive energy (NDVI) and temperature, and to precipitation, and compare the data from the FB and SKB with these relationships. We further compare our local richness estimates with that of similar habitats worldwide, and regional ant richness with estimates derived from other regions. The local ant species richness of the FB and SKB falls within the general global pattern relating ant richness to energy, and is similar to that in comparable habitats elsewhere. At a regional scale, the richness of ants across all of our sites is not exceptional by comparison with other regional estimates from across the globe. Conclusions/Significance: Local richness of ants in the FB and SKB is not exceptional by global standards. Initial analyses suggest that regional diversity is also not exceptional for the group. It seems unlikely that the mechanisms which have contributed to the development of extraordinarily high regional plant diversity in these biomes have had a strong influence on the ants. © 2012 Braschler et al.
Abstract.
Armsworth PR, Acs S, Dallimer M, Gaston KJ, Hanley N, Wilson P (2012). The cost of policy simplification in conservation incentive programs.
Ecology Letters,
15(5), 406-414.
Abstract:
The cost of policy simplification in conservation incentive programs
Incentive payments to private landowners provide a common strategy to conserve biodiversity and enhance the supply of goods and services from ecosystems. To deliver cost-effective improvements in biodiversity, payment schemes must trade-off inefficiencies that result from over-simplified policies with the administrative burden of implementing more complex incentive designs. We examine the effectiveness of different payment schemes using field parameterized, ecological economic models of extensive grazing farms. We focus on profit maximising farm management plans and use bird species as a policy-relevant indicator of biodiversity. Common policy simplifications result in a 49-100% loss in biodiversity benefits depending on the conservation target chosen. Failure to differentiate prices for conservation improvements in space is particularly problematic. Additional implementation costs that accompany more complicated policies are worth bearing even when these constitute a substantial proportion (70% or more) of the payments that would otherwise have been given to farmers. © 2012 Blackwell Publishing Ltd/CNRS.
Abstract.
Cianciaruso MV, Silva IA, Batalha MA, Gaston KJ, Petchey OL (2012). The influence of fire on phylogenetic and functional structure of woody savannas: Moving from species to individuals.
Perspectives in Plant Ecology, Evolution and Systematics,
14(3), 205-216.
Abstract:
The influence of fire on phylogenetic and functional structure of woody savannas: Moving from species to individuals
Fire is a key determinant of tropical savanna structure and functioning. High fire frequencies are expected to assemble closely related species with a restricted range of functional trait values. Here we determined the effect of fire on phylogenetic and functional diversity of woody species and individuals in savanna communities under different fire frequencies. We found phylogenetic signals for one third of the functional traits studied. High numbers of fires simultaneously led to phylogenetic overdispersion and functional clustering when communities were represented by mean trait values with all traits that putatively should be affected or respond to fire. This finding is important, because it shows that the relationship between ecological processes and the phylogenetic structure of communities is not straightforward. Thus, we cannot always assume that close relatives are more similar in their ecological features. However, when considering a different set of traits representing different plant strategies (fire resistance/avoidance, physiological traits and regeneration traits), the results were not always congruent. When asking how communities are assembled in terms of individuals (not species) the outcome was different from the species-based approach, suggesting that the realised trait values - rather than mean species trait values - have an important role in driving community assembly. Thus, intraspecific trait variability should be taken into account if we want fully to improve our mechanistic understanding of assembly rules in plant communities. © 2011 Perspectives in Plant Ecology, Evolution and Systematics.
Abstract.
Armsworth PR, Fishburn IS, Davies ZG, Gilbert J, Leaver N, Gaston KJ (2012). The size, concentration and growth of biodiversity-conservation nonprofits.
BioScience,
62(3), 271-281.
Abstract:
The size, concentration and growth of biodiversity-conservation nonprofits
Nonprofit organizations play a critical role in efforts to conserve biodiversity. Their success in this regard will be determined in part by how effectively individual nonprofits and the sector as a whole are structured. One of the most fundamental questions about an organization's structure is how large it should be, with the logical counterpart being how concentrated the whole sector should be. We review empirical patterns in the size, concentration, and growth of over 1700 biodiversity-conservation nonprofits registered for tax purposes in the United States within the context of relevant economic theory. Conservation-nonprofit sizes vary by six to seven orders of magnitude and are positively skewed. Larger nonprofits access more revenue streams and hold more of their assets in land and buildings than smaller or midsized nonprofits do. The size of conservation nonprofits varies with the ecological focus of the organization, but the growth rates of nonprofits do not. © 2012 Hinterthuer. ISSN.
Abstract.
Edmondson JL, Davies ZG, McCormack SA, Gaston KJ, Leake JR (2011). Are soils in urban ecosystems compacted? a citywide analysis.
Biol Lett,
7(5), 771-774.
Abstract:
Are soils in urban ecosystems compacted? a citywide analysis.
Soil compaction adversely influences most terrestrial ecosystem services on which humans depend. This global problem, affecting over 68 million ha of agricultural land alone, is a major driver of soil erosion, increases flood frequency and reduces groundwater recharge. Agricultural soil compaction has been intensively studied, but there are no systematic studies investigating the extent of compaction in urban ecosystems, despite the repercussions for ecosystem function. Urban areas are the fastest growing land-use type globally, and are often assumed to have highly compacted soils with compromised functionality. Here, we use bulk density (BD) measurements, taken to 14 cm depth at a citywide scale, to compare the extent of surface soil compaction between different urban greenspace classes and agricultural soils. Urban soils had a wider BD range than agricultural soils, but were significantly less compacted, with 12 per cent lower mean BD to 7 cm depth. Urban soil BD was lowest under trees and shrubs and highest under herbaceous vegetation (e.g. lawns). BD values were similar to many semi-natural habitats, particularly those underlying woody vegetation. These results establish that, across a typical UK city, urban soils were in better physical condition than agricultural soils and can contribute to ecosystem service provision.
Abstract.
Author URL.
Moilanen A, Anderson BJ, Eigenbrod F, Heinemeyer A, Roy DB, Gillings S, Armsworth PR, Gaston KJ, Thomas CD (2011). Balancing alternative land uses in conservation prioritization.
Ecological Applications,
21(5), 1419-1426.
Abstract:
Balancing alternative land uses in conservation prioritization
Pressure on ecosystems to provide various different and often conflicting services is immense and likely to increase. The impacts and success of conservation prioritization will be enhanced if the needs of competing land uses are recognized at the planning stage. We develop such methods and illustrate them with data about competing land uses in Great Britain, with the aim of developing a conservation priority ranking that balances between needs of biodiversity conservation, carbon storage, agricultural value, and urban development potential. While both carbon stocks and biodiversity are desirable features from the point of view of conservation, they compete with the needs of agriculture and urban development. In Britain the greatest conflicts exist between biodiversity and urban areas, while the largest carbon stocks occur mostly in Scotland in areas with low agricultural or urban pressure. In our application, we were able successfully to balance the spatial allocation of alternative land uses so that conflicts between them were much smaller than had they been developed separately. The proposed methods and software, Zonation, are applicable to structurally similar prioritization problems globally. © 2011 by the Ecological Society of America.
Abstract.
Gaston KJ (2011). Common ecology.
BioScience,
61(5), 354-362.
Abstract:
Common ecology
In contrast to their rarity, the commonness of species has historically received surprisingly little explicit attention from ecologists. However, this situation is changing. Here I review the current understanding of the nature of commonness, with particular emphasis on the dynamics and causes of this state, as well as on its ecological and evolutionary implications. Depending on the focal issue, common species can variously have lower, greater, or similar per capita influences compared with rare ones. Importantly, however, these influences almost invariably remain strong because of the high numbers of individuals and local occurrences in taxonomic assemblages contributed by the relatively few species that are common. The importance of these species highlights the significance of deepening concerns over the declines of many common species and the vital need for a balanced approach to maintaining their commonness while also addressing the more familiar conservation issue of preventing the loss of rare species. © 2011 by American Institute of Biological Sciences. All rights reserved.
Abstract.
Renforth P, Edmondson J, Leake JR, Gaston KJ, Manning DAC (2011). Designing a carbon capture function into urban soils.
Proceedings of the Institution of Civil Engineers: Urban Design and Planning,
164(2), 121-128.
Abstract:
Designing a carbon capture function into urban soils
Soils, if designed and managed correctly, can retain carbon from the atmosphere as accumulated organic matter, refractory forms of carbon (e.g. biochar) or stable, inorganic, carbonate minerals. This soil 'carbon capture function' is highly applicable to the constructed environment in urban areas and should be considered when planning for new or existing developments. The total carbon capture potential of soils in cities may be as high as 7 Mt/year within the UK using biochar and accumulated carbonate minerals, which is equivalent in significance to other forms of geoengineering. Furthermore, soil and vegetation management practices may be implemented to accumulate plant-derived organic carbon in urban soils. The potential for substantial soil-based carbon sequestration in urban environments has yet to be realised, and the varied praxis of soil carbon capture presents accreditation and regulatory challenges to the planning system which need to be resolved.
Abstract.
Tang Z, Fang J, Sun J, Gaston KJ (2011). Effectiveness of protected areas in maintaining plant production.
PLoS ONE,
6(4).
Abstract:
Effectiveness of protected areas in maintaining plant production
Given the central importance of protected area systems in local, regional and global conservation strategies, it is vital that there is a good understanding of their effectiveness in maintaining ecological functioning. Here, we provide, to our knowledge, the first such global analysis, focusing on plant production, a "supporting" ecosystem function necessary for multiple other ecosystem services. We use data on the normalized difference vegetation index (NDVI) as a measure of variation in plant production in the core, boundary and surroundings of more than 1000 large protected areas over a 25 year period. Forested protected areas were higher (or similar), and those non-forested were lower (or similar), in NDVI than their surrounding areas, and these differences have been sustained. The differences from surrounding areas have increased for evergreen broadleaf forests and barren grounds, decreased for grasslands, and remained similar for deciduous forests, woodlands, and shrublands, reflecting different pressures on those surroundings. These results are consistent with protected areas being effective both in the representation and maintenance of plant production. However, widespread overall increases in NDVI during the study period suggest that plant production within the core of non-forested protected areas has become higher than it was in the surroundings of those areas in 1982, highlighting that whilst the distinctiveness of protected areas from their surroundings has persisted the nature of that difference has changed. © 2011 Tang et al.
Abstract.
Marini L, Bona E, Kunin WE, Gaston KJ (2011). Exploring anthropogenic and natural processes shaping fern species richness along elevational gradients.
Journal of Biogeography,
38(1), 78-88.
Abstract:
Exploring anthropogenic and natural processes shaping fern species richness along elevational gradients
Aim- (1) to explore the impact of land use, climate and environmental heterogeneity on fern species richness along a complete elevational gradient, and (2) to evaluate the relative importance of the three groups of variables within different elevational intervals.Location- a temperate mountain region (55,507-km2) of Italy on the southern border of the European Alps divided into a regular grid of 1476 cells (grain 35.7-km2).Methods- We applied multiple regression (spatial and non-spatial) to determine the relative influence of the three groups of variables on species richness, including variation partitioning at two scales. We considered the whole gradient (all 1476 cells) to explain the overall elevational pattern of species richness, and we grouped the cells into elevational intervals of 500-m in order to evaluate the explanatory power of the predictors within different zones along the gradient.Results- Species richness showed a hump-shaped pattern with elevation, forming a plateau between 800 and 1500-m. The lowest species richness was found in warm and relatively dry disturbed lowlands. Moving upwards, the greatest species richness was found in forest-dominated mid-elevations with high environmental heterogeneity. At high elevations dominated by open natural habitats, where temperature and precipitation were relatively low, species richness declined but less sharply than in the lowlands. Although it was impossible to separate the effects of the three groups of predictors along the whole gradient, the analysis of separate elevational intervals shed light on their relative importance. The decline of species richness within lowlands was mainly related to a combined effect of deforestation and low environmental heterogeneity. In the middle part of the gradient, habitat heterogeneity and topographic roughness were positively associated with species richness. The richness decline within high-elevation areas was related mostly to climatic constraints.Main conclusions- Human impact due to land-use modifications strongly affects the elevational pattern of species richness. It is therefore increasingly important to adopt a multiple-hypothesis approach, taking anthropogenic effects explicitly into account when describing ecological processes along elevational gradients. © 2010 Blackwell Publishing Ltd.
Abstract.
Dupré J (2011). Foreword. Carving Nature at its Joints: Natural Kinds in Metaphysics and Science
Mora C, Aburto-Oropeza O, Ayala-Bocos A, Ayotte PM, Banks S, Bauman AG, Beger M, Bessudo S, Booth DJ, Brokovich E, et al (2011). Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes.
PLoS Biology,
9(4).
Abstract:
Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes
Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e. for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas. © 2011 Mora et al.
Abstract.
Gouws EJ, Gaston KJ, Chown SL (2011). Intraspecific body size frequency distributions of insects.
PLoS ONE,
6(3).
Abstract:
Intraspecific body size frequency distributions of insects
Although interspecific body size frequency distributions are well documented for many taxa, including the insects, intraspecific body size frequency distributions (IaBSFDs) are more poorly known, and their variation among mass-based and linear estimates of size has not been widely explored. Here we provide IaBSFDs for 16 species of insects based on both mass and linear estimates and large sample sizes (n≥100). In addition, we review the published IaBSFDs for insects, though doing so is complicated by their under-emphasis in the literature. The form of IaBSFDs can differ substantially between mass-based and linear measures. Nonetheless, in non-social insects they tend to be normally distributed (18 of 27 species) or in fewer instances positively skewed. Negatively skewed distributions are infrequently reported and log transformation readily removes the positive skew. Sexual size dimorphism does not generally cause bimodality in IaBSFDs. The available information on IaBSFDs in the social insects suggests that these distributions are usually positively skewed or bimodal (24 of 30 species). However, only c. 15% of ant genera are polymorphic, suggesting that normal distributions are probably more common, but less frequently investigated. Although only 57 species, representing seven of the 29 orders of insects, have been considered here, it appears that whilst IaBSFDs are usually normal, other distribution shapes can be found in several species, though most notably among the social insects. By contrast, the interspecific body size frequency distribution is typically right-skewed in insects and in most other taxa. © 2011 Gouws et al.
Abstract.
Davies ZG, Edmondson JL, Heinemeyer A, Leake JR, Gaston KJ (2011). Mapping an urban ecosystem service: Quantifying above-ground carbon storage at a city-wide scale.
Journal of Applied Ecology,
48(5), 1125-1134.
Abstract:
Mapping an urban ecosystem service: Quantifying above-ground carbon storage at a city-wide scale
Despite urbanization being a major driver of land-use change globally, there have been few attempts to quantify and map ecosystem service provision at a city-wide scale. One service that is an increasingly important feature of climate change mitigation policies, and with other potential benefits, is biological carbon storage. We examine the quantities and spatial patterns of above-ground carbon stored in a typical British city, Leicester, by surveying vegetation across the entire urban area. We also consider how carbon density differs in domestic gardens, indicative of bottom-up management of private green spaces by householders, and public land, representing top-down landscape policies by local authorities. Finally, we compare a national ecosystem service map with the estimated quantity and distribution of above-ground carbon within our study city. An estimated 231521 tonnes of carbon is stored within the above-ground vegetation of Leicester, equating to 3·16kgCm-2 of urban area, with 97·3% of this carbon pool being associated with trees rather than herbaceous and woody vegetation. Domestic gardens store just 0·76kgCm-2, which is not significantly different from herbaceous vegetation landcover (0·14kgCm-2). The greatest above-ground carbon density is 28·86kg Cm-2, which is associated with areas of tree cover on publicly owned/managed sites. Current national estimates of this ecosystem service undervalue Leicester's contribution by an order of magnitude. Synthesis and applications. The UK government has recently set a target of an 80% reduction in greenhouse gas emissions, from 1990 levels, by 2050. Local authorities are central to national efforts to cut carbon emissions, although the reductions required at city-wide scales are yet to be set. This has led to a need for reliable data to help establish and underpin realistic carbon emission targets and reduction trajectories, along with acceptable and robust policies for meeting these goals. Here, we illustrate the potential benefits of accounting for, mapping and appropriately managing above-ground vegetation carbon stores, even within a typical densely urbanized European city. © 2011 the Authors. Journal of Applied Ecology © 2011 British Ecological Society.
Abstract.
Gaspar C, Gaston KJ, Borges PAV, Cardoso P (2011). Selection of priority areas for arthropod conservation in the Azores archipelago.
Journal of Insect Conservation,
15(5), 671-684.
Abstract:
Selection of priority areas for arthropod conservation in the Azores archipelago
The largest standardised database available to date for arthropods in native forests of the Azores archipelago was used to determine the minimum optimal set of native forest fragments needed to accomplish four different targets of species occurrence (presence-absence) and abundance (20,50 and 80%) using different groups of arthropods and all data combined. The results showed that occurrence and 20% abundance targets gave similar optimal solutions for most of the groups considered. At least one fragment on each of the seven studied islands was required to accomplish any occurrence and abundance target. To achieve 80% of abundance for all species, all fragments were necessary and to guarantee 50% of the overall abundance of endemics, 17 out of 18 native forests were needed. A suggestion is made to apply a measure of biotic integrity related to disturbance to select, among alternative optimal solutions, the set of areas that will help to guarantee the viability of populations. Some guidelines for the selection of priority areas for conservation in the Azores are presented. © 2010 Springer Science+Business Media B.V.
Abstract.
Holland RA, Eigenbrod F, Armsworth PR, Anderson BJ, Thomas CD, Heinemeyer A, Gillings S, Roy DB, Gaston KJ (2011). Spatial covariation between freshwater and terrestrial ecosystem services.
Ecological Applications,
21(6), 2034-2048.
Abstract:
Spatial covariation between freshwater and terrestrial ecosystem services
To inform the design and implementation of land-use policies that consider the variety of goods and services people derive from ecosystems, it is essential to understand spatial patterns of individual services, how multiple services relate to each other, and how these relationships vary across spatial scales and localities. Despite the importance of freshwater as a determinant of regional economic and human demographic patterns, there are surprisingly few studies that map the provision of a range of services associated with the quality of the aquatic environment. Here we examine relationships between indicators of riverine water and associated habitat quality, freshwater biodiversity, three terrestrial ecosystem services, and terrestrial biodiversity across England and Wales. The results indicate strong associations between our indicators of freshwater services. However, a comparison of these indicators of freshwater services with other ecosystem services (carbon storage, agricultural production, recreation) and biodiversity of species of conservation concern in the surrounding terrestrial landscape shows no clear relationships. While there are potential policy "win-wins" for the protection of multiple services shown by associations between indicators of freshwater services and carbon storage in upland areas of Britain, the other ecosystem services showed either negative or no relationships with the indicators of freshwater services. We also consider the influence that spatial scale has on these relationships using River Basin Districts. Our results indicate that relationships between indicators of services can change dramatically depending on the societal pressures and other regional conditions. Thus, the delivery of multiple ecosystem services requires the development of regional strategies, or of national strategies that take account of regional variation. © 2011 by the Ecological Society of America.
Abstract.
Dallimer M, Tang Z, Bibby PR, Brindley P, Gaston KJ, Davies ZG (2011). Temporal changes in greenspace in a highly urbanized region.
Biol Lett,
7(5), 763-766.
Abstract:
Temporal changes in greenspace in a highly urbanized region.
The majority of the world's population now lives in towns and cities, and urban areas are expanding faster than any other land-use type. In response to this phenomenon, two opposing arguments have emerged: whether cities should 'sprawl' into the wider countryside, or 'densify' through the development of existing urban greenspace. However, these greenspaces are increasingly recognized as being central to the amelioration of urban living conditions, supporting biodiversity conservation and ecosystem service provision. Taking the highly urbanized region of England as a case study, we use data from a variety of sources to investigate the impact of national-level planning policy on temporal patterns in the extent of greenspace in cities. Between 1991 and 2006, greenspace showed a net increase in all but one of 13 cities. However, the majority of this gain occurred prior to 2001, and greenspace has subsequently declined in nine cities. Such a dramatic shift in land use coincides with policy reforms in 2000, which favoured densification. Here, we illustrate the dynamic and policy-responsive nature of urban land use, thereby highlighting the need for a detailed investigation of the trade-offs associated with different mechanisms of urban densification to optimize and secure the diverse benefits associated with greenspaces.
Abstract.
Author URL.
Resit Akçakaya H, Mace GM, Gaston KJ, Regan H, Punt A, Butchart SHM, Keith DA, Gärdenfors U (2011). The SAFE index is not safe. Frontiers in Ecology and the Environment, 9(9), 485-486.
Greve M, Chown SL, van Rensburg BJ, Dallimer M, Gaston KJ (2011). The ecological effectiveness of protected areas: a case study for South African birds.
Animal Conservation,
14(3), 295-305.
Abstract:
The ecological effectiveness of protected areas: a case study for South African birds
While the importance of individual protected areas (PAs) to biological conservation is widely acknowledged, rather few empirical studies have explicitly attempted to assess their ecological effectiveness. Significantly, this includes consideration of how well they represent the biodiversity of taxonomic groups for which the designation of these areas was not a primary or intentional goal. Here, we provide one of the most detailed comparisons to date of the avian biodiversity found inside and outside PAs, focusing on three PAs distributed widely across South Africa. Typically, bird assemblages were richer, with a higher density, and a different structural and functional composition inside than outside the PAs. Importantly, insectivore richness was much higher inside than outside, and the converse was true of granivores. Overall, these findings suggest that PAs do indeed provide valuable repositories for native biodiversity, with species richness, density and species composition being substantially different beyond their bounds. With human land-use increasing in South Africa, and habitat transformation recognized as a major and growing threat to biodiversity, such differences are expected to become greater. © 2011 the Authors. Animal Conservation © 2011 the Zoological Society of London.
Abstract.
Eigenbrod F, Bell VA, Davies HN, Heinemeyer A, Armsworth PR, Gaston KJ (2011). The impact of projected increases in urbanization on ecosystem services.
Proc Biol Sci,
278(1722), 3201-3208.
Abstract:
The impact of projected increases in urbanization on ecosystem services.
Alteration in land use is likely to be a major driver of changes in the distribution of ecosystem services before 2050. In Europe, urbanization will probably be the main cause of land-use change. This increase in urbanization will result in spatial shifts in both supplies of ecosystem services and the beneficiaries of those services; the net outcome of such shifts remains to be determined. Here, we model changes in urban land cover in Britain based on large (16%) projected increases in the human population by 2031, and the consequences for three different services--flood mitigation, agricultural production and carbon storage. We show that under a scenario of densification of urban areas, the combined effect of increasing population and loss of permeable surfaces is likely to result in 1.7 million people living within 1 km of rivers with at least 10 per cent increases in projected peak flows, but that increasing suburban 'sprawl' will have little effect on flood mitigation services. Conversely, losses of stored carbon and agricultural production are over three times as high under the sprawl as under the 'densification' urban growth scenarios. Our results illustrate the challenges of meeting, but also of predicting, future demands and patterns of ecosystem services in the face of increasing urbanization.
Abstract.
Author URL.
Sandel B, Arge L, Dalsgaard B, Davies RG, Gaston KJ, Sutherland WJ, Svenning JC (2011). The influence of late quaternary climate-change velocity on species endemism.
Science,
334(6056), 660-664.
Abstract:
The influence of late quaternary climate-change velocity on species endemism
The effects of climate change on biodiversity should depend in part on climate displacement rate (climate-change velocity) and its interaction with species' capacity to migrate. We estimated Late Quaternary glacial-interglacial climate-change velocity by integrating macroclimatic shifts since the Last Glacial Maximum with topoclimatic gradients. Globally, areas with high velocities were associated with marked absences of small-ranged amphibians, mammals, and birds. The association between endemism and velocity was weakest in the highly vagile birds and strongest in the weakly dispersing amphibians, linking dispersal ability to extinction risk due to climate change. High velocity was also associated with low endemism at regional scales, especially in wet and aseasonal regions. Overall, we show that low-velocity areas are essential refuges for Earth's many small-ranged species.
Abstract.
Holland RA, Eigenbrod F, Armsworth PR, Anderson BJ, Thomas CD, Gaston KJ (2011). The influence of temporal variation on relationships between ecosystem services.
Biodiversity and Conservation,
20(14), 3285-3294.
Abstract:
The influence of temporal variation on relationships between ecosystem services
A growing literature aims to identify areas of congruence in the provision of multiple ecosystem goods and services. However, little attention has been paid to the effect that temporal variation in the provision of such services may have on understanding of these relationships. Due to a lack of temporally and spatially replicated monitoring surveys, such relationships are often assessed using data from disparate time periods. Utilising temporally replicated data for indices of freshwater quality and agricultural production we demonstrate that through time the biophysical values of ecosystem services may vary in a spatially non-uniform way. This can lead to differing conclusions being reached about the strength of relationships between services, which in turn has implications for the prioritisation of areas for management of multiple services. We present this first analysis to illustrate the effect that the use of such temporally disparate datasets may have, and to highlight the need for further research to assess under what circumstances temporal variation of this sort will have the greatest impact. © 2011 Springer Science+Business Media B.V.
Abstract.
Booth JE, Gaston KJ, Evans KL, Armsworth PR (2011). The value of species rarity in biodiversity recreation: a birdwatching example.
Biological Conservation,
144(11), 2728-2732.
Abstract:
The value of species rarity in biodiversity recreation: a birdwatching example
Wildlife viewing recreation offers conservationists opportunities for education and generating revenue but can also have detrimental ecological impacts. To manage these opportunities and impacts effectively, a better understanding is needed of what people value in wildlife viewing events. We examine the relationship between species rarity and value for wildlife viewing recreation. We undertook visitor counts of birdwatchers attending rare (vagrant) bird sightings and collected home postcodes to assess the distances these individuals travelled to achieve these sightings. We also undertook visitor counts at common bird viewing locations for comparison. We regressed birdwatcher numbers against rarity, site protection status, time the bird had been on site and day of the week when the count took place. We undertook these analyses for rare bird sightings only, using a continuous measure of rarity, and for both rare and common species combined, using a categorical rarity index. Species rarity was the clearest predictor of visitor numbers in both the analyses. When studying rare birds only, we found the functional form of the relationship between rarity and visitor numbers to be inverse and asymptotic. Individuals also travelled further to see rarer species. However, while exceptional numbers of visitors attended exceptionally rare bird sightings, the marginal value of rarity appeared to be relatively low. Despite the opportunity for revenue raising and education provided by rare bird sightings, a comparison of visitor numbers at sightings inside and outside protected areas showed no evidence that managers of protected areas capitalise on these opportunities. © 2011 Elsevier Ltd.
Abstract.
Loram A, Warren P, Thompson K, Gaston K (2011). Urban Domestic Gardens: the Effects of Human Interventions on Garden Composition.
ENVIRONMENTAL MANAGEMENT,
48(4), 808-824.
Author URL.
Evans KL, Chamberlain DE, Hatchwell BJ, Gregory RD, Gaston KJ (2011). What makes an urban bird?.
Global Change Biology,
17(1), 32-44.
Abstract:
What makes an urban bird?
Urban development is increasing across the globe. This poses a major threat to biodiversity, which is often relatively poor in towns and cities. Despite much interest in identifying species' traits that can predict their responses to environmental degradation this approach has seldom been used to assess which species are particularly vulnerable to urban development. Here we explore this issue, exploiting one of the best available datasets on species' responses to towns and cities in a highly urbanized region, comprising avian densities across approximately 3000 British urban and rural 1 km × 1 km grid cells. We find that the manner in which species' responses to urbanization is measured has a marked influence on the nature of associations between these responses and species' ecological and life history traits. We advocate that future studies should use continuous indices of responses that take relative urban and rural densities into account, rather than using urban densities in isolation, or a binary response recording the presence/absence of a species in towns and cities. Contrary to previous studies we find that urban development does not select against avian long-distance migrants and insectivores, or species with limited annual fecundity and dispersal capacity. There was no evidence that behavioural flexibility, as measured by relative brain size, influenced species' responses to urban environments. In Britain, generalist species, as measured by niche position rather than breadth, are favoured by urban development as are, albeit to a lesser extent, those that feed on plant material and nest above the ground. Our results suggest that avian biodiversity in towns and cities in urbanizing regions will be promoted by providing additional resources that are currently scarce in urban areas, and developing suitable environments for ground-nesting species. © 2010 Blackwell Publishing Ltd.
Abstract.
Evans KL, Hatchwell BJ, Parnell M, Gaston KJ (2010). A conceptual framework for the colonisation of urban areas: the blackbird Turdus merula as a case study.
Biol Rev Camb Philos Soc,
85(3), 643-667.
Abstract:
A conceptual framework for the colonisation of urban areas: the blackbird Turdus merula as a case study.
Despite increasing interest in urban ecology the factors limiting the colonisation of towns and cities by species from rural areas are poorly understood. This is largely due to the lack of a detailed conceptual framework for this urbanisation process, and of sufficient case studies. Here, we develop such a framework. This draws upon a wide range of ecological and evolutionary theory and the increasing number of studies of how the markedly divergent conditions in urban and rural areas influence the traits of urban populations and the structure of urban assemblages. We illustrate the importance of this framework by compiling a detailed case study of spatial and temporal variation in the urbanisation of the blackbird Turdus merula. Our framework identifies three separate stages in the urbanisation process: (i) arrival, (ii) adjustment, and (iii) spread. The rate of progress through each stage is influenced by environmental factors, especially human attitudes and socio-economic factors that determine the history of urban development and the quality of urban habitats, and by species' ecological and life-history traits. Some traits can positively influence progression through one stage, but delay progression through another. Rigorous assessment of the factors influencing urbanisation should thus ideally pay attention to the different stages. Urbanisation has some similarities to invasion of exotic species, but the two clearly differ. Invasion concerns geographic range expansion that is external to the species' original geographic range, whilst urbanisation typically relates to filling gaps within a species' original range. This process is exemplified by the blackbird which is now one of the commonest urban bird species throughout its Western Palearctic range. This is in stark contrast to the situation 150 years ago when the species was principally confined to forest. Blackbird urbanisation was first recorded in Germany in 1820, yet some European cities still lack urban blackbirds. This is especially so in the east, where urbanisation has spread more slowly than in the west. The timing of blackbird urbanisation exhibits a marked spatial pattern, with latitude and longitude explaining 76% of the variation. This strong spatial pattern contrasts with the weaker spatial pattern in timing of urbanisation exhibited by the woodpigeon Columba palumbus (with location explaining 39% of the variation), and with the very weak spatial pattern in timing of black-billed magpie Pica pica urbanisation (in which location explains 12% of the variation). Strong spatial patterns in timing of urbanisation are more compatible with the leap-frog urbanisation model, in which urban adapted or imprinted birds colonise other towns and cities, than with the independent urbanisation model, in which urban colonisation events occur independently of each other. Spatial patterns in isolation do not, however, confirm one particular model. Factors relating to the arrival and adjustment stages appear particularly likely to have influenced the timing of blackbird urbanisation. Spatial variation in the occurrence of urban populations and the timing of their establishment creates opportunities to assess the factors regulating urbanisation rates, and how the composition of urban assemblages develops as a result. These are major issues for urban ecology.
Abstract.
Author URL.
Dallimer M, Marini L, Skinner AMJ, Hanley N, Armsworth PR, Gaston KJ (2010). Agricultural land-use in the surrounding landscape affects moorland bird diversity.
Agriculture, Ecosystems and Environment,
139(4), 578-583.
Abstract:
Agricultural land-use in the surrounding landscape affects moorland bird diversity
A multi-scale approach was used to investigate the response of the moorland bird community to agricultural land-use in the surrounding matrix and local-scale vegetation characteristics. For the assemblage of upland specialist species, there was a negative association with the extent of intensively managed grassland at the 750. m spatial scale. This had a greater influence on richness than the local vegetation characteristic of the moorland itself. Similarly, for species of conservation concern, richness was enhanced by increased landscape-level woodland cover at the 750. m scale. Such assemblage-level associations can mask the responses of individual species. For example, some upland specialists, such as the red grouse and golden plover, were negatively associated with intensive grassland in the landscape, while other species of conservation concern, notably curlew, lapwing and snipe all showed positive relationships. These results indicate that upland agriculture at the landscape-scale is integral to maintaining the richness and composition of UK moorland birds and hence land management actions for moorland should not be limited to that habitat alone. © 2010 Elsevier B.V.
Abstract.
Davies RG, Irlich UM, Chown SL, Gaston KJ (2010). Ambient, productive and wind energy, and ocean extent predict global species richness of procellariiform seabirds.
Global Ecology and Biogeography,
19(1), 98-110.
Abstract:
Ambient, productive and wind energy, and ocean extent predict global species richness of procellariiform seabirds
Aims: Tests of the energy hypothesis for the large-scale distribution of species richness have largely been concerned with the influence of two alternative forms of environmental energy, temperature and energy from primary productivity, both of which (at least in terrestrial systems) peak within the tropics. Taxa showing extra-tropical diversity peaks present a potential challenge to the generality of species-energy theory. One such group are pelagic seabirds of the order Procellariiformes that show not only an extra-tropical diversity peak but one confined to the Southern Ocean, hence a highly asymmetric one. They are distinct in being exceptionally adapted to take advantage of wind energy, which they may rely on for long-distance ocean foraging for the patchy resources needed to meet their energetic needs. Wind represents a readily available source of kinetic energy, shows a strong latitudinal gradient, and has been largely omitted from species-energy theory. Moreover, maximal benefits of wind are likely to be afforded in areas of greatest available contiguous ocean extent. We compare the relative importance of wind speed, ocean productivity (chlorophyll concentration), air temperature and available ocean extent (distance) in explaining large-scale global distribution of procellariiform species richness across the world's oceans. Location: Global, oceanic. Methods: Hierarchical partitioning, model selection, ordinary least squares (OLS) and spatial generalized least squares (GLS) regression. Results: Hierarchical partitioning of non-spatial regression models indicates that ocean distance is the most important predictor of procellariiform species richness followed by wind speed and then temperature. In contrast, that of spatial regression models indicates the roughly equal importance of ocean distance and temperature, followed by wind speed. Although contributing additional model fit, ocean productivity is consistently the weakest predictor. Best-fit models include all four predictors and explain 67% of observed variation. The species-productivity relationship is negative overall, while the species-temperature relationship is hump-shaped. In contrast, ocean distance and wind speed are positively associated with species richness. Conclusions: Large-scale procellariiform species richness distribution may represent a trade-off in the use of different energy forms, being highest in Southern Ocean areas where productive energy and temperature are relatively low, but where available ocean foraging extent and wind energy required to utilize it are near-maximal. © 2009 Blackwell Publishing Ltd.
Abstract.
Gaspar C, Gaston KJ, Borges PAV (2010). Arthropods as surrogates of diversity at different spatial scales.
Biological Conservation,
143(5), 1287-1294.
Abstract:
Arthropods as surrogates of diversity at different spatial scales
This study evaluates the effectiveness of taxonomic, colonization and trophic groups of arthropods from native forests of the Azores archipelago as surrogates of the diversity of other arthropod groups and of the remaining arthropods. Consistency in the performance of surrogates was tested across three spatial scales and using two measures of diversity. Pitfall and beating samples from 109 transects, 18 forest fragments and seven islands were analysed. The results showed that Araneae, Hemiptera and small orders taxonomic groups; native, endemic and introduced colonization groups; and the herbivores trophic group were consistent surrogates of the remaining diversity across the three spatial scales analysed, for both alpha and dissimilarity diversities. However, none of the subsets considered was significantly related with all of the other subsets at any of the three spatial scales. The effectiveness of surrogacy was dependent on the spatial level considered, and groups behaved inconsistently depending on the measure of diversity used. The value of a group as a diversity surrogate should be evaluated for a study area for a given spatial scale and diversity measure, in accordance with the scale and measure that will be used for biodiversity assessments and monitoring programs in that area. © 2010 Elsevier Ltd. All rights reserved.
Abstract.
Chown SL, Gaston KJ (2010). Body size variation in insects: a macroecological perspective.
Biological Reviews,
85(1), 139-169.
Abstract:
Body size variation in insects: a macroecological perspective
Body size is a key feature of organisms and varies continuously because of the effects of natural selection on the size-dependency of resource acquisition and mortality rates. This review provides a critical and synthetic overview of body size variation in insects from a predominantly macroecological (large-scale temporal and spatial) perspective. Because of the importance of understanding the proximate determinants of adult size, it commences with a brief summary of the physiological mechanisms underlying adult body size and its variation, based mostly on findings for the model species Drosophila melanogaster and Manduca sexta. Variation in nutrition and temperature have variable effects on critical weight, the interval to cessation of growth (or terminal growth period) and growth rates, so influencing final adult size. Ontogenetic and phylogenetic variation in size, compensatory growth, scaling at the intra- and interspecific levels, sexual size dimorphism, and body size optimisation are then reviewed in light of their influences on individual and species body size frequency distributions. Explicit attention is given to evolutionary trends, including gigantism, Cope's rule and the rates at which size change has taken place, and to temporal ecological trends such as variation in size with succession and size-selectivity during the invasion process. Large-scale spatial variation in size at the intraspecific, interspecific and assemblage levels is considered, with special attention being given to the mechanisms proposed to underlie clinal variation in adult body size. Finally, areas particularly in need of additional research are identified. © 2009 Cambridge Philosophical Society.
Abstract.
Blackburn TM, Gaston KJ, Parnell M (2010). Changes in non-randomness in the expanding introduced avifauna of the world.
Ecography,
33(1), 168-174.
Abstract:
Changes in non-randomness in the expanding introduced avifauna of the world
The identities of bird species introduced to areas beyond the limits of their native geographic ranges have historically depended on a combination of societal demands for species with certain characteristics, and the availability of species for capture, transport and release. However, both societal demands and availability have changed over time, which should also change the characteristics of species more recently added to the list of introduced birds. Here, we quantify temporal changes in selectivity of introduced bird species by comparing the characteristics of 423 species listed in the seminal catalogue of introduced birds (Long, J. L. 1981. Introduced birds of the world. - David and Charles, London) with those of 122 species that have been introduced but are not listed in Long (1981). We demonstrate differences between these two groups of species in the frequencies with which different taxa are represented, in the geographic range sizes of species, and in their biogeographic regions of origin, but not in body mass. Both groups also differ from bird species in general in terms of geographic range sizes, body masses, and taxonomic composition. We relate the observed differences in the characteristics of species listed or unlisted in Long (1981) to changes in the changes in attitudes, legislation and vectors of transport relating to exotic species. We conclude by noting that the utility of published catalogues of introduced bird species is increasingly being eroded by the continued liberation and establishment of bird species. © 2010 the Author. Journal compilation © 2010 Ecography.
Abstract.
Eigenbrod F, Armsworth PR, Anderson BJ, Heinemeyer A, Gillings S, Roy DB, Thomas CD, Gaston KJ (2010). Error propagation associated with benefits transfer-based mapping of ecosystem services.
Biological Conservation,
143(11), 2487-2493.
Abstract:
Error propagation associated with benefits transfer-based mapping of ecosystem services
An increasing number of studies are taking the important first step in global efforts to conserve key ecosystem services by mapping their spatial distributions. However, a lack of primary data for most services in most places has largely forced such mapping exercises to be based on proxies. The common way of producing these proxies is through benefits transfer-based mapping, in which estimates of the values of services are obtained from a small region for particular land cover types, and then extrapolated to a larger area for these same types. However, the errors that may result from such extrapolations are poorly understood. Here, we separate the generalization errors associated with benefits transfer mapping into three constituent components - uniformity, sampling, and regionalization error - and evaluate their effects using primary data for four ecosystem services in England. Variation in ecosystem services within a particular land cover type (uniformity error) alone led to a poor fit to primary data for most services; sampling effects (sampling error) and extrapolating from a small region to a larger area (regionalization error) led to substantial, but highly variable, additional reductions in the fit to primary data. We also show that combining multiple ecosystem services into a single layer is likely to be even more problematic as it contains the errors in each of the constituent layers. These errors are sufficiently large to undermine decisions that might be based on such extrapolated maps. Greatly improved mapping of the actual distributions of ecosystem services is therefore needed to achieve the goal of conserving these vital assets. © 2010 Elsevier Ltd.
Abstract.
Dallimer M, Gaston KJ, Skinner AMJ, Hanley N, Acs S, Armsworth PR (2010). Field-level bird abundances are enhanced by landscape-scale agri-environment scheme uptake.
Biol Lett,
6(5), 643-646.
Abstract:
Field-level bird abundances are enhanced by landscape-scale agri-environment scheme uptake.
Despite two decades of agri-environment schemes (AESs) aimed at mitigating farmland biodiversity losses, the evidence that such programmes actually benefit biodiversity remains limited. Using field-level surveys, we assess the effectiveness of AESs in enhancing bird abundances in an upland area of England, where schemes have been operating for over 20 years. In such a region, the effects of AESs should be readily apparent, and we predict that bird abundances will co-vary with both field- and landscape-scale measures of implementation. Using an information theoretic approach, we found that, for abundances of species of conservation concern and upland specialists, measures of AES implementation and habitat type at both scales appear in the most parsimonious models. Field-level bird abundances are higher where more of the surrounding landscape is included in an AES. While habitat remains a more influential predictor, we suggest that landscape-scale implementation results in enhanced bird abundances. Hence, measures of the success of AESs should consider landscape-wide benefits as well as localized impacts.
Abstract.
Author URL.
Chown SL, Gaston KJ, van Kleunen M, Clusella-Trullas S (2010). Population responses within a landscape matrix: a macrophysiological approach to understanding climate change impacts.
Evolutionary Ecology,
24(3), 601-616.
Abstract:
Population responses within a landscape matrix: a macrophysiological approach to understanding climate change impacts
Global environmental change (GEC) is a significant concern. However, forecasting the outcomes of this change for species and ecosystems remains a major challenge. In particular, predicting specific changes in systems where initial conditions, instabilities, and model errors have large impacts on the outcome is problematic. Indeed, predictive community ecology has been deemed unworthy of pursuit or an unreachable goal. However, new developments in large-scale biology provide ways of thinking that might substantially improve forecasts of local and regional impacts of climate change. Most notably, these are the explicit recognition of the regional and landscape contexts within which populations reside, the matrix approach that can be used to investigate the consequences of population variation across space and within assemblages, and the development of macrophysiology, which explicitly seeks to understand the ecological implications of physiological variation across large spatial and temporal scales. Here we explore how a combination of these approaches might promote further understanding and forecasting of the effects of global climate change and perhaps other GEC drivers on biodiversity. We focus on the population level, examining the ways in which environmental variation might be translated through performance and its plasticity to variation in demography. © Springer Science+Business Media B.V. 2009.
Abstract.
Braschler B, Mahood K, Karenyi N, Gaston KJ, Chown SL (2010). Realizing a synergy between research and education: How participation in ant monitoring helps raise biodiversity awareness in a resource-poor country.
Journal of Insect Conservation,
14(1), 19-30.
Abstract:
Realizing a synergy between research and education: How participation in ant monitoring helps raise biodiversity awareness in a resource-poor country
Biodiversity-rich, resource-poor countries need to allocate scarce resources to the competing goals of identifying and monitoring their biodiversity and educating their populace about it. Often only relatively wealthy individuals participate in biodiversity-related volunteering, while the poor are left on the margins. We present a case study that shows how monitoring and education can be combined. South African high school scholars from mostly disadvantaged communities participated in ant monitoring in transformed sites and received lessons using their own data. The project provides baseline data on an important insect group in a region where invertebrate monitoring is rare. Participation in a real study enhances the scholars' interest in science and direct interaction with scientists allows them to enquire about careers they might not otherwise consider. Here we outline how the project works, what participants learnt, and demonstrate that the data provide insights into ant diversity and the effects of landscape transformation. © Springer Science+Business Media B.V. 2009.
Abstract.
Eigenbrod F, Anderson BJ, Armsworth PR, Heinemeyer A, Gillings S, Roy DB, Thomas CD, Gaston KJ (2010). Representation of ecosystem services by tiered conservation strategies.
Conservation Letters,
3(3), 184-191.
Abstract:
Representation of ecosystem services by tiered conservation strategies
In human-dominated regions, protected areas are complemented by other conservation strategies (e.g. restrictive zoning, incentive payments) to maintain biodiversity and other ecosystem services. These strategies are often not mutually exclusive, with many areas covered by multiple (tiered) management strategies. However, it is not known whether tiering increases (or decreases) representation of ecosystem services. Here, we compare the representation of four ecosystem services by areas protected by both tiered and single conservation strategies (protected areas, restrictive zoning, and incentive payments to landowners) in a human-dominated region (England). Tiering always coincided with the highest levels of stored carbon, sometimes coincided with high biodiversity and agricultural production, but never coincided with high recreational value. We also show that tiering is common in England and biased towards upland areas. Future evaluations of the effectiveness of conservation strategies should consider the degree of overlap of the different strategies fully to understand which are most effective. ©2010 Wiley Periodicals, Inc.
Abstract.
Cerdeira JO, Pinto LS, Cabeza M, Gaston KJ (2010). Species specific connectivity in reserve-network design using graphs.
Biological Conservation,
143(2), 408-415.
Abstract:
Species specific connectivity in reserve-network design using graphs
Systematic conservation planning applications based solely on the presence/absence of a large number of species are not sufficient to guarantee their persistence in highly fragmented landscapes. Recent developments have thus incorporated much desired spatial design considerations, and reserve-network connectivity has received increased attention. Nonetheless, connectivity is often determined without regard to species-specific responses to habitat fragmentation. But species differ in their dispersal ability and habitat requirements, making proximate priority areas necessary for some species, while undesirable for others. We present a novel approach that incorporates species-specific connectivity needs in reserve-network design. Importantly, our method differs from previous approaches in that connectivity is not part of the objective function, but part of the constraints, thus avoiding typical undesirable trade-off that may result in high connectivity for some species but null connectivity for others. We use graphs to describe the dispersal pattern of each species and our goal is to identify minimum sets of reserves with connected sites for each of the species. This is not a trivial problem and we present three algorithms, one heuristic and two integer cutting algorithms that guarantee optimality, based on different 0-1 linear programming formulations. Applications to simulated data show that one of the algorithms that guarantee optimality is superior to the other, although both have limited application due to the number of sites and species they can manage. Remarkably, the heuristic can obtain very satisfactory solutions in short computational times, surpassing the limitations of the exact algorithms. © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Armsworth PR, Armsworth AN, Compton N, Cottle P, Davies I, Emmett BA, Fandrich V, Foote M, Gaston KJ, Gardiner P, et al (2010). The ecological research needs of business.
Journal of Applied Ecology,
47(2), 235-243.
Abstract:
The ecological research needs of business
Businesses have an unrivalled ability to mobilize human, physical and financial capital, often manage large land holdings, and draw on resources and supply products that impact a wide array of ecosystems. Businesses therefore have the potential to make a substantial contribution to arresting declines in biodiversity and ecosystem services. To realize this potential, businesses require support from researchers in applied ecology to inform how they measure and manage their impacts on, and opportunities presented to them by, biodiversity and ecosystem services. We reviewed papers in leading applied ecology journals to assess the research contribution from existing collaborations involving businesses. We reviewed applications to, and grants funded by, the UK's Natural Environment Research Council for evidence of public investment in such collaborations. To scope opportunities for expanding collaborations with businesses, we conducted workshops with three sectors (mining and quarrying, insurance and manufacturing) in which participants identified exemplar ecological research questions of interest to their sector. Ten to fifteen per cent of primary research papers in Journal of Applied Ecology and Ecological Applications evidenced business involvement, mostly focusing on traditional rural industries (farming, fisheries and forestry). The review of UK research council funding found that 35% of applications mentioned business engagement, while only 1% of awarded grants met stricter criteria of direct business involvement. Some questions identified in the workshops aim to reduce costs from businesses' impacts on the environment and others to allow businesses to exploit new opportunities. Some questions are designed to inform long-term planning undertaken by businesses, but others would have more immediate commercial applications. Finally, some research questions are designed to streamline and make more effective those environmental policies that affect businesses. Business participants were forward-looking regarding ecological questions and research. For example, representatives from mining and quarrying companies emphasized the need to move beyond biodiversity to consider how ecosystems function, while those from the insurance sector stressed the importance of ecology researchers entering into new types of interdisciplinary collaboration. Synthesis and applications. Businesses from a variety of sectors demonstrated a clear interest in managing their impacts on, and exploiting opportunities created by, ecosystem services and biodiversity. To achieve this, businesses are asking diverse ecological research questions, but publications in leading applied ecology journals and research council funding reveal limited evidence of direct engagement with businesses. This represents a missed opportunity for ecological research findings to see more widespread application. © 2010 the Authors. Journal compilation © 2010 British Ecological Society.
Abstract.
Acs S, Hanley N, Dallimer M, Gaston KJ, Robertson P, Wilson P, Armsworth PR (2010). The effect of decoupling on marginal agricultural systems: Implications for farm incomes, land use and upland ecology.
Land Use Policy,
27(2), 550-563.
Abstract:
The effect of decoupling on marginal agricultural systems: Implications for farm incomes, land use and upland ecology
In many parts of Europe, decades of production subsidies led to the steady intensification of agriculture in marginal areas. The recent decoupling of subsidies from production decisions means that the future of farming in these areas is uncertain. For example, in the uplands of the United Kingdom, an area important both for biodiversity conservation and ecosystem service provision, hill farmers steadily increased stocking densities in response to headage payments but must now reconfigure farm businesses to account for the shift to the Single Farm Payment scheme. We examined hill farming in the Peak District National Park as a case study into the future of marginal agriculture after decoupling. We surveyed 44 farm businesses and from this identified six representative farm types based on enterprise mix and land holdings. We developed linear programming models of production decisions for each farm type to examine the impacts of policy changes, comparing the effects of decoupling with and without agri-environment and hill farm support, and evaluating the effects of removal of the Single Farm Payment. The main effects of decoupling are to reduce stocking rates, and to change the mix of livestock activities. Agri-environmental schemes mediate the income losses from decoupling, and farmers are predicted to maximise take up of new Environmental Stewardship programmes, which have both positive and negative feedback effects on livestock numbers. Finally, removal of the Single Farm Payment leads to negative net farm incomes, and some land abandonment. These changes have important implications for ongoing debates about how ecological service flows can be maintained from upland areas, and how marginal upland farming communities can be sustained. © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Eigenbrod F, Armsworth PR, Anderson BJ, Heinemeyer A, Gillings S, Roy DB, Thomas CD, Gaston KJ (2010). The impact of proxy-based methods on mapping the distribution of ecosystem services.
Journal of Applied Ecology,
47(2), 377-385.
Abstract:
The impact of proxy-based methods on mapping the distribution of ecosystem services
An increasing number of studies are examining the distribution and congruence of ecosystem services, often with the goal of identifying areas that will provide multiple ecosystem service 'hotspots'. However, there is a paucity of data on most ecosystem services, so proxies (e.g. estimates of a service for a particular land cover type) are frequently used to map their distribution. To date, there has been little attempt to quantify the effects of using proxies on distribution maps of ecosystem services, despite the potentially large errors associated with such data sets. Here, we provide the first study examining the effects of using proxies on ecosystem service maps and the degree of spatial congruence of these maps with primary data, using England as a case study. We show that land cover based proxies provide a poor fit to primary data surfaces for biodiversity, recreation and carbon storage, and that correlations between ecosystem services change depending on whether primary or proxy data are used for the analyses. The poor fit of proxies to primary data was also evident when we selected hotspots of single ecosystem services, and consistency between raw and modelled surfaces was extremely low when considering the locations that were coincident hotspots for multiple services. Synthesis and applications. Proxies may be suitable for identifying broad-scale trends in ecosystem services, but even relatively good proxies are likely to be unsuitable for identifying hotspots or priority areas for multiple services. © 2010 the Authors. Journal compilation © 2010 British Ecological Society.
Abstract.
Smith RM, Thompson K, Warren PH, Gaston KJ (2010). Urban domestic gardens (XIII): Composition of the bryophyte and lichen floras, and determinants of species richness.
Biological Conservation,
143(4), 873-882.
Abstract:
Urban domestic gardens (XIII): Composition of the bryophyte and lichen floras, and determinants of species richness
Private, residential gardens form a substantial proportion of the undeveloped land in urban areas. Evaluating their role in supporting biodiversity is crucial to (i) predicting which plant and animal species can persist in towns and cities, (ii) understanding the regional impacts of urbanisation, and (iii) guiding sympathetic garden management by owners. To obtain baseline information on a poorly-studied component of garden biodiversity, we measured the size and composition of the cryptogam assemblages in 61 domestic gardens in the city of Sheffield, UK. A total of 67 bryophyte and 77 lichen taxa were recorded. Bryophytes ranged from 3 to 24 species per garden, with a mean richness of 11.3 species; lichens ranged from 2 to 30, with a mean of 14.9 species. Stone substrates supported the highest lichen richness, although minor substrates contributed unique species. Just over one fifth of bryophyte species were recorded in grass lawns, and these were more widespread than those of other habitats. Most cryptogams were scarce, with around one quarter of both bryophytes and lichens occurring in single gardens, and only 10% were found in more than half of the gardens. Garden area - correlated with substrate richness - and garden altitude were the only two factors explaining variation in cryptogam richness (bryophytes 39.1%, lichens 32.4%). Positive correlations existed among bryophyte, lichen and vascular plant richness, and these were only partially mediated by the effect of garden area. Therefore the opportunity remains for garden owners to support cryptogam richness, the most effective action being to enhance substrate diversity. © 2010 Elsevier Ltd. All rights reserved.
Abstract.
Gaston KJ (2010). Valuing common species.
Science,
327(5962), 154-155.
Abstract:
Valuing common species
Ecologically common species play key roles in terrestrial and marine ecosystems, yet are also the main victims of habitat loss, ecosystem degradation, and overexploitation.
Abstract.
Cant-Salazar L, Gaston KJ (2010). Very large protected areas and their contribution to terrestrial biological conservation.
BioScience,
60(10), 808-818.
Abstract:
Very large protected areas and their contribution to terrestrial biological conservation
A high proportion of global coverage by protected areas is composed of relatively few very large protected areas (vLPAs); it is therefore important to understand their contribution to biological conservation. Here, using fresh analyses and a review of literature, we examine five particular contentions about existing terrestrial vLPAs: that they (1) are highly biased in environmental coverage, (2) contain low numbers of overall and rare species, (3) make limited contributions toward meeting global conservation prioritization schemes, (4) contain substantial areas of wilderness, and (5) are relatively immune to threatening processes. These contentions are generally supported. The principal contribution of vLPAs is substantial global coverage of wilderness, and more broadly, of areas where human influence is much reduced. There is also some evidence that individual vLPAs can retain unusually intact species assemblages and significant populations of particular species of regional or global conservation concern, and they can have marked regional conservation significance. The current level of threat to many vLPAs, and the challenges for their management, therefore are substantive concerns. © 2010 by American Institute of Biological Sciences. All rights reserved.
Abstract.
Booth JE, Gaston KJ, Armsworth PR (2010). Who benefits from recreational use of protected areas?.
Ecology and Society,
15(3).
Abstract:
Who benefits from recreational use of protected areas?
Public support for protected areas depends, in part, upon clear demonstrations of the importance of the ecosystem services provided by these areas. However, only a limited number of studies have examined the value of protected areas in providing these services, and even less work has assessed how equitably these benefits are distributed across society. We used on-site surveys to characterize people who derived recreational benefit from a set of areas in the United Kingdom that were originally protected for their conservation value. We found that an unrepresentative subset of society enjoyed this benefit. Site visitor populations were biased towards older people and men, and minority groups were starkly underrepresented, comprising only 1% of overall visitors. When the characteristics of visitors were examined, the more privileged sectors of society were found to have received disproportionate benefits. These biases persisted across weekday and weekend visits and whether sites were considered altogether or individually. Conservation goals will only be met if broad public support for the natural environment is engaged and maintained, for example, through nature recreation. However, our results suggest that at present a worrying disconnect exists between public conservation efforts and much of society. © 2010 by the author(s).
Abstract.
Dallimer M, Tinch D, Acs S, Hanley N, Southall HR, Gaston KJ, Armsworth PR (2009). 100 years of change: Examining agricultural trends, habitat change and stakeholder perceptions through the 20th century.
Journal of Applied Ecology,
46(2), 334-343.
Abstract:
100 years of change: Examining agricultural trends, habitat change and stakeholder perceptions through the 20th century
1. The 20th century has witnessed substantial increases in the intensity of agricultural land management, much of which has been driven by policies to enhance food security and production. The knock-on effects in agriculturally dominated landscapes include habitat degradation and biodiversity loss. We examine long-term patterns of agricultural and habitat change at a regional scale, using the Peak District of northern England as a case study. As stakeholders are central to the implementation of successful land-use policy, we also assess their perceptions of historical changes. 2. In the period 1900 to 2000, there was a fivefold rise in sheep density, along with higher cattle density. We found a reduction in the number of farms, evidence of a shift in land ownership patterns, and increased agricultural specialization, including the virtual disappearance of upland arable production. 3. Despite previous studies showing a substantial loss in heather cover, we found that there had been no overall change in the proportion of land covered by dwarf shrub moor. Nonetheless, turnover rates were high, with only 55% of sampled sites maintaining dwarf shrub moor coverage between 1913 and 2000. 4. Stakeholders identified many of the changes revealed by the historical data, such as increased sheep numbers, fewer farms and greater specialization. However, other land-use changes were not properly described. For instance, although there had been no overall change in the proportion of dwarf shrub moor and the size of the rural labour force had not fallen, stakeholders reported a decline in both. Spatial heterogeneity of the changes, shifting baselines and problems with historical data sources might account for some of these discrepancies. 5. Synthesis and applications. A marked increase in sheep numbers, combined with general agricultural intensification, have been the dominant land-use processes in the Peak District during the 20th century. Stakeholders only correctly perceived some land-use changes. Policy and management objectives should therefore be based primarily on actual historical evidence. However, understanding stakeholder perceptions and how they differ from, or agree with, the available evidence will contribute to the successful uptake of land management policies and partly determine the costs of policy implementation. © 2009 British Ecological Society.
Abstract.
Davies ZG, Fuller RA, Loram A, Irvine KN, Sims V, Gaston KJ (2009). A national scale inventory of resource provision for biodiversity within domestic gardens.
Biological Conservation,
142(4), 761-771.
Abstract:
A national scale inventory of resource provision for biodiversity within domestic gardens
The human population is increasingly disconnected from nature due to urbanisation. To counteract this phenomenon, the UK government has been actively promoting wildlife gardening. However, the extent to which such activities are conducted and the level of resource provision for biodiversity (e.g. food and nesting sites) within domestic gardens remains poorly documented. Here we generate estimates for a selection of key resources provided within gardens at a national scale, using 12 survey datasets gathered across the UK. We estimate that 22.7 million households (87% of homes) have access to a garden. Average garden size is 190 m2, extrapolating to a total area of 432,924 ha. Although substantial, this coverage is still an order of magnitude less than that of statutory protected areas. Approximately 12.6 million (48%) households provide supplementary food for birds, 7.4 million of which specifically use bird feeders. Similarly, there are a minimum of 4.7 million nest boxes within gardens. These figures equate to one bird feeder for every nine potentially feeder-using birds in the UK, and at least one nest box for every six breeding pairs of cavity nesting birds. Gardens also contain 2.5-3.5 million ponds and 28.7 million trees, which is just under a quarter of all trees occurring outside woodlands. Ongoing urbanisation, characterised by increased housing densities, is inevitable throughout the UK and elsewhere. The important contribution domestic gardens make to the green space infrastructure in residential areas must be acknowledged, as their reduction will impact biodiversity conservation, ecosystem services, and the well-being of the human population. © 2008 Elsevier Ltd. All rights reserved.
Abstract.
Marini L, Fontana P, Battisti A, Gaston KJ (2009). Agricultural management, vegetation traits and landscape drive orthopteran and butterfly diversity in a grassland-forest mosaic: a multi-scale approach.
Insect Conservation and Diversity,
2(3), 213-220.
Abstract:
Agricultural management, vegetation traits and landscape drive orthopteran and butterfly diversity in a grassland-forest mosaic: a multi-scale approach
Most ecological processes at the population and community level act on multiple spatial scales. We identified the influence of grassland management, vegetation traits and landscape on orthopteran and butterfly diversity in 44 meadows located in a forest-dominated region in the Italian Alps. The meadows were sampled in landscapes characterised by different proportions of woody vegetation and grasslands quantified at 11 spatial scales (95-3000 m). 2. We applied a multi-scale approach to investigate the scale-dependent effects of landscape. Then, we built generalised linear models (Poisson and log-link function) to test simultaneously vegetation traits and landscape variables on insect species richness. 3. High fertilisation and cutting frequency created tall, species-poor plant communities. This change reduced orthopteran diversity by providing an unsuitable sward structure, and butterfly diversity by creating disturbed plant communities with low species richness and abundance of flowering forbs and host plants. 4. The proportion of woody vegetation had a strong positive effect on the richness of both groups at the smallest spatial scale (95 m), indicating the importance of undisturbed vegetation in the surrounding of mown meadows. The effect tended to disappear with increasing spatial extent. 5. A multi-scale approach was necessary to identify the effects of landscape factors in this study system. Conservation measures should endorse the maintenance of species-rich, sparse and short plant communities by reducing organic fertilisation and cutting frequency. However, these schemes should also promote the presence of undisturbed woody vegetation in the immediate surrounding landscape or at least should prevent the complete mowing of large areas. © 2009 the Royal Entomological Society.
Abstract.
Chamberlain DE, Cannon AR, Toms MP, Leech DI, Hatchwell BJ, Gaston KJ (2009). Avian productivity in urban landscapes: a review and meta-analysis.
Ibis,
151(1), 1-18.
Abstract:
Avian productivity in urban landscapes: a review and meta-analysis
There is an urgent need to thoroughly review and comprehend the effects of urbanization on wildlife in order to understand both the ecological implications of increasing urbanization and how to mitigate its threat to biodiversity globally. We examined patterns in comparative productivity of urban and non-urban passerine birds, using published estimates from paired comparisons, and by reviewing and developing explanations in terms of resources, competitors, predators and other specifically urban environmental factors. The most consistent patterns were for earlier lay dates, lower clutch size, lower nestling weight and lower productivity per nesting attempt in urban landscapes; these were supported by a formal meta-analysis. Nest failure rates did not show consistent patterns across the species considered. We suggest that food availability is a key driver of differences in passerine demography between landscapes. In urban habitats, human-provided food may improve adult condition over winter, leading to earlier lay dates and, in some species, to higher survival and higher breeding densities, but paucity of natural food may lead to lower productivity per nesting attempt. We demonstrate that additional comparative research is needed on a wider range of species, on the effects of natural and human-provided food availability, and on the differences in survival and dispersal between urban and non-urban populations. Importantly, better-targeted research and monitoring is needed in areas that are at greatest threat from urbanization, especially in the developing world. © 2008 the Authors.
Abstract.
Sachs JD, Baillie JEM, Sutherland WJ, Armsworth PR, Ash N, Beddington J, Blackburn TM, Collen B, Gardiner B, Gaston KJ, et al (2009). Biodiversity conservation and the millennium development goals.
Science,
325(5947), 1502-1503.
Abstract:
Biodiversity conservation and the millennium development goals
Any near-term gains in reducing extreme poverty will be maintained only if environmental sustainability is also achieved.
Abstract.
Simeoni M, Dawson DA, Gentle LK, Coiffait L, Wolff K, Evans KL, Gaston KJ, Hatchwell BJ (2009). Characterization of 38 microsatellite loci in the European blackbird, Turdus merula (Turdidae, AVES).
Mol Ecol Resour,
9(6), 1520-1526.
Abstract:
Characterization of 38 microsatellite loci in the European blackbird, Turdus merula (Turdidae, AVES).
We characterized 38 microsatellite loci in the European blackbird, Turdus merula. Thirty-seven loci were identified by testing 242 loci that had been originally isolated in other avian species. One additional locus was isolated from a European blackbird genomic library. All loci were characterized in 20-29 blackbirds from a population in the Czech Republic and displayed between two and 16 alleles, with observed heterozygosity ranging from 0.04 to 1.00. Thirty-seven loci could be assigned a chromosome location in the zebra finch (Taeniopygia guttata) genome based on sequence homology.
Abstract.
Author URL.
Armsworth PR, Gaston KJ, Hanley ND, Ruffell RJ (2009). Contrasting approaches to statistical regression in ecology and economics: FORUM.
Journal of Applied Ecology,
46(2), 265-268.
Abstract:
Contrasting approaches to statistical regression in ecology and economics: FORUM
Conservation and natural resource management challenges are as much social problems as biological ones. In recognition of this fact, ecologists and economists work increasingly closely together. We discuss one barrier to effective integration of the two disciplines: put simply, many ecologists and economists approach statistical regression differently. 2. Regression techniques provide the most commonly used approach for empirical analyses of land management decisions. Researchers from each discipline attribute differing importance to a range of possibly conflicting design criteria when formulating regression analyses. 3. Ecologists commonly attribute greater importance to spatial autocorrelation and parsimony than do economists when designing regressions. Economists often attribute greater importance than ecologists to concerns about endogeneity and conformance with a priori theoretical expectations. 4. Synthesis and applications. The differing importance attributed to different design characteristics may reflect a process of cultural drift within each discipline. Greater interdisciplinary collaboration can counteract this process by stimulating the flow of ideas and techniques across disciplinary boundaries. © 2009 British Ecological Society.
Abstract.
Marini L, Gaston KJ, Prosser F, Hulme PE (2009). Contrasting response of native and alien plant species richness to environmental energy and human impact along alpine elevation gradients.
Global Ecology and Biogeography,
18(6), 652-661.
Abstract:
Contrasting response of native and alien plant species richness to environmental energy and human impact along alpine elevation gradients
Aim: We tested whether the species-energy and species-human relationships vary between native and both naturalized and casual alien species richness when other environmental variables had been taken into account. Location: Trento Province, a region (c. 6200 km2) on the southern border of the European Alps (Italy), subdivided into 156 contiguous (c. 37.5 km2) cells and ranging in elevation from 66 to 3769 m. Methods: Data were separated into three subsets, representing richness of natives, naturalized aliens and casual aliens and separately related to temperature, human population and various environmental correlates of plant species diversity. We applied ordinary least squares and simultaneous autoregressive regressions to identify potential contrasting responses of the three plant status subsets and hierarchical partitioning to evaluate the relative importance of the predictor variables. Results: Variation in alien plant species richness along the region was almost entirely explained by temperature and human population density. The relationships were positive but strongly curvilinear. Native species richness was less strongly related to either factor but was positively related to the presence of calcareous bedrock. Native species richness had a decelerating positive relationship with temperature (R2 = 55%), whereas naturalized and casual aliens had a positive accelerating relationship explaining 86% and 62% of the variation in richness, respectively. Native species richness had a positive decelerating relationship with population density (R2 = 42%), whilst both alien subsets had a positive accelerating relationship. Main conclusions: Alien species richness was higher in areas with the most rich and diverse assemblages of native species. Areas at high altitudes are not especially prone to alien invasion due to energy constraints, low propagule pressure and disturbance, even considering a potential increased in temperature. Thus, if we consider future environmental change, we should expect a stronger response of aliens than natives in the currently warm, urbanized, low-altitude areas than in cold, high-altitude areas where human population density is low. © 2009 Blackwell Publishing Ltd.
Abstract.
Petchey OL, Gaston KJ (2009). Dendrograms and measures of functional diversity: a second instalment. Oikos, 118(7), 1118-1120.
Eigenbrod F, Anderson BJ, Armsworth PR, Heinemeyer A, Jackson SF, Parnell M, Thomas CD, Gaston KJ (2009). Ecosystem service benefits of contrasting conservation strategies in a human-dominated region.
Proc Biol Sci,
276(1669), 2903-2911.
Abstract:
Ecosystem service benefits of contrasting conservation strategies in a human-dominated region.
The hope among policy-makers and scientists alike is that conservation strategies designed to protect biodiversity also provide direct benefits to people by protecting other vital ecosystem services. The few studies that have examined the delivery of ecosystem services by existing conservation efforts have concentrated on large, 'wilderness'-style biodiversity reserves. However, such reserves are not realistic options for densely populated regions. Here, we provide the first analyses that compare representation of biodiversity and three other ecosystem services across several contrasting conservation strategies in a human-dominated landscape (England). We show that small protected areas and protected landscapes (restrictive zoning) deliver high carbon storage and biodiversity, while existing incentive payment (agri-environment) schemes target areas that offer little advantage over other parts of England in terms of biodiversity, carbon storage and agricultural production. A fourth ecosystem service-recreation-is under-represented by all three strategies. Our findings are encouraging as they illustrate that restrictive zoning can play a major role in protecting natural capital assets in densely populated regions. However, trade-offs exist even among the four ecosystem services we considered, suggesting that a portfolio of conservation and sustainability investments will be needed to deliver both biodiversity and the other ecosystem services demanded by society.
Abstract.
Author URL.
Evans KL, Gaston KJ, Sharp SP, McGowan A, Simeoni M, Hatchwell BJ (2009). Effects of urbanisation on disease prevalence and age structure in blackbird Turdus merula populations.
Oikos,
118(5), 774-782.
Abstract:
Effects of urbanisation on disease prevalence and age structure in blackbird Turdus merula populations
Despite increasing interest in urban ecology most attention has focussed on describing changes in assemblage composition and structure along urbanisation gradients, whilst relatively little research has focussed on the mechanisms behind these changes. Ecological theory predicts that alterations in biotic interactions are particularly likely to arise, especially with regard to disease risk. Here, we report on differences in prevalence of avian malaria and tick infection and intensity in 11 paired urban and rural blackbird Turdus merula populations from across the western Palearctic. We find large and consistent reductions in tick prevalence and intensity in urban areas. There are also large reductions in the prevalence of avian malaria in many, but not all, urban areas. The proportion of first year birds in urban populations is significantly lower than that in rural ones, and across the more natural rural sites southerly populations contain fewer first years than northern ones. These patterns are expected to arise if survival rates are higher in urban areas, and are negatively correlated with latitude. © 2009 Oikos.
Abstract.
Petchey OL, Gaston KJ (2009). Effects on ecosystem resilience of biodiversity, extinctions, and the structure of regional species pools.
Theoretical Ecology,
2(3), 177-187.
Abstract:
Effects on ecosystem resilience of biodiversity, extinctions, and the structure of regional species pools
Resilience is a general concept that aims to help understand how ecosystems respond to disturbances such as extinctions and invasions. Here, we propose a measure of one aspect of resilience, RX, which is one minus the expected change in functional diversity (X) caused by a species extinction or addition. We show how two components of biodiversity, species richness and functional diversity, and the structure of regional species pools affect this measure. Variation in species richness and in functional diversity have opposite effects on RX. Speciose assemblages generally have higher RX than depauperate ones, whereas functionally diverse assemblages have low RX relative to functionally depauperate ones. The effect of an extinction on RX reflects this tradeoff. In our analyses, extinctions usually cause only a small decrease in both functional diversity and RX. However, extinctions sometimes cause a large reduction in functional diversity and then tend to increase RX. Regional assemblages containing all rather unique species tend to result in speciose assemblages with relatively low RX and in low richness assemblages with relatively high RX. The opposite is true of regional assemblages containing functionally similar species. Information about the processes that structure regional assemblages will therefore increase understanding of ecosystem resilience. Generally, these results suggest that management for biodiversity may not always result in management for resilience. © Springer Science+Business Media B.V. 2009.
Abstract.
Gaston KJ (2009). Geographic range limits of species.
Proceedings of the Royal Society B: Biological Sciences,
276(1661), 1391-1393.
Abstract:
Geographic range limits of species
Understanding the forms that the geographic range limits of species take, their causes and their consequences are key issues in ecology and evolutionary biology. They are also topics on which understanding is advancing rapidly. This themed issue of Proc. R. Soc. B focuses on the wide variety of current research perspectives on the nature and determinants of the limits to geographic ranges. The contributions address important themes, including the roles and influences of dispersal limitation, species interactions and physiological limitation, the broad patterns in the structure of geographic ranges, and the fundamental question of why at some point species no longer evolve the ability to overcome the factors constraining their distributions and thus fail to continue to spread. In this introduction, these contributions are placed in the wider context of these broad themes. © 2009 the Royal Society.
Abstract.
Gaston KJ (2009). Geographic range limits: Achieving synthesis.
Proceedings of the Royal Society B: Biological Sciences,
276(1661), 1395-1406.
Abstract:
Geographic range limits: Achieving synthesis
Understanding of the determinants of species' geographic range limits remains poorly integrated. In part, this is because of the diversity of perspectives on the issue, and because empirical studies have lagged substantially behind developments in theory. Here, I provide a broad overview, drawing together many of the disparate threads, considering, in turn, how influences on the terms of a simple single-population equation can determine range limits. There is theoretical and empirical evidence for systematic changes towards range limits under some circumstances in each of the demographic parameters. However, under other circumstances, no such changes may take place in particular parameters, or they may occur in a different direction, with limitation still occurring. This suggests that (i) little about range limitation can categorically be inferred from many empirical studies, which document change in only one demographic parameter, (ii) there is a need for studies that document variation in all of the parameters, and (iii) in agreement with theoretical evidence that range limits can be formed in the presence or absence of hard boundaries, environmental gradients or biotic interactions, there may be few general patterns as to the determinants of these limits, with most claimed generalities at least having many exceptions. © 2009 the Royal Society.
Abstract.
Olson VA, Davies RG, Orme CDL, Thomas GH, Meiri S, Blackburn TM, Gaston KJ, Owens IPF, Bennett PM (2009). Global biogeography and ecology of body size in birds.
Ecology Letters,
12(3), 249-259.
Abstract:
Global biogeography and ecology of body size in birds
In 1847, Karl Bergmann proposed that temperature gradients are the key to understanding geographic variation in the body sizes of warm-blooded animals. Yet both the geographic patterns of body-size variation and their underlying mechanisms remain controversial. Here, we conduct the first assemblage-level global examination of 'Bergmann's rule' within an entire animal class. We generate global maps of avian body size and demonstrate a general pattern of larger body sizes at high latitudes, conforming to Bergmann's rule. We also show, however, that median body size within assemblages is systematically large on islands and small in species-rich areas. Similarly, while spatial models show that temperature is the single strongest environmental correlate of body size, there are secondary correlations with resource availability and a strong pattern of decreasing body size with increasing species richness. Finally, our results suggest that geographic patterns of body size are caused both by adaptation within lineages, as invoked by Bergmann, and by taxonomic turnover among lineages. Taken together, these results indicate that while Bergmann's prediction based on physiological scaling is remarkably accurate, it is far from the full picture. Global patterns of body size in avian assemblages are driven by interactions between the physiological demands of the environment, resource availability, species richness and taxonomic turnover among lineages. © 2009 Blackwell Publishing Ltd/CNRS.
Abstract.
Devine-Wright P, Irvine K, Payne S, Fuller R, Painter B, Gaston K (2009). Green space, soundscape and urban sustainability: an interdisciplinary,empirical study.
Local Environment,
14(2), 155-172.
Abstract:
Green space, soundscape and urban sustainability: an interdisciplinary,empirical study
This paper addresses two typically separate issues contributing to urban quality of life: increasing noise levels and declining quality of public green space. Drawing from environmental psychology, ecology and acoustical methods, this interdisciplinary research studied the soundscapes of three green spaces in a UK city through interviews with 70 park users, the measurement of habitat and recording of sound levels. The data reveal a prevalence of mechanical sounds and a hierarchy of preference for natural over people and mechanical sounds. There was a link between sound levels, both objective and perceived, and the type of sounds heard. The presence of these sounds varied across sites in part due to the ecological qualities of the place, specifically the presence of birds and shrub vegetation. The results suggest that people’s opportunity to access quiet, natural places in urban areas can be enhanced by improving the ecological quality of urban green spaces through targeted planning and design.
Abstract.
Evans KL, Newson SE, Gaston KJ (2009). Habitat influences on urban avian assemblages.
Ibis,
151(1), 19-39.
Abstract:
Habitat influences on urban avian assemblages
Urbanization is increasing across the globe and there is growing interest in urban ecology and a recognition that developed areas may be important for conservation. We review the factors influencing urban avian assemblages, focusing on habitat type and anthropogenic resource provision, and analyse data from a common bird monitoring scheme to assess some of these issues. The review suggests that (1) local factors are more important than regional ones in determining the species richness of urban avian assemblages, raising the potential for the management of urban sites to deliver conservation; (2) habitat fragmentation frequently influences urban avian assemblages, with the effects of patch size being greater than those of isolation, and (3) urban bird assemblages appear to respond positively to increasing the structural complexity, species richness of woody vegetation and supplementary feeding, and negatively to human disturbance. Data from Britain's Breeding Bird Survey, combined with habitat data obtained from aerial photographs, were used to assess a number of these issues at the resolution of 1-km squares. Green-space constituted 45% of these squares, and domestic gardens contributed 50% of this green-space, though their contribution to large continuous patches of green-space was negligible. There was no significant positive correlation between the densities of individual species in urban areas and surrounding rural areas. Rural species richness declined with increasing latitude, but urban species richness was not correlated with latitude. This contrast contributes to slightly higher avian species richness in rural squares in Southern England than urban ones. Occupancy and abundance were strongly positively correlated in urban avian assemblages, and some indicator species of conservation concern occurred in few urban areas and at low densities. Such species will require conservation action to be precisely targeted within urban areas. of the urban indicators of conservation concern, only the House Sparrow Passer domesticus and Common Starling Sturnus vulgaris were more abundant in urban than rural areas. Moreover, the densities of these two species were strongly and positively correlated, indicating that they may be limited by shared resources, such as nest-sites or supplementary food. There was little evidence that high densities of nest-predating corvids were associated with reduced densities of their prey species. Species richness and the densities of individual species frequently declined with an increasing number of buildings. Current trends for the densification of many British urban areas are thus likely to be detrimental for many bird species. © 2008 the Authors.
Abstract.
Fuller RA, Tratalos J, Gaston KJ (2009). How many birds are there in a city of half a million people?.
Diversity and Distributions,
15(2), 328-337.
Abstract:
How many birds are there in a city of half a million people?
Aim : Urban environments are often characterized as supporting a few abundant, generalist species best adapted to living alongside humans, and as such, cities are seen as agents of biotic homogenization. However, there are surprisingly few descriptions of biological populations found in cities. Here, we provide the first complete citywide population estimates of birds for any UK city, and examine the conservation status of the assemblage in comparison with the country's avifauna at large. Location : Sheffield city, central UK Methods : We surveyed birds in every 500 m × 500 m square across the 160 km 2 of the city. Using a Distance sampling protocol, we estimated bird population sizes for the city and compared these with the size of the human population. We also compared the conservation status of the city's avian population with that of birds across the UK as a whole. Results : Aggregation of population estimates for the 77 species observed during the surveys produced a total estimate of 602,995 (95% confidence interval (CI): 404,565-942,573) breeding birds, equating to 1.18 birds per person. The size of the non-breeding population was similar at 578,603 (464,396-728,574) individuals, or 1.13 birds per person. Surveys revealed only three non-native species, but relatively few species of national conservation concern. However, some species of conservation concern achieved very high population densities within the city, and the overall density of birds was more than six times that of the nation at large. Main conclusions : If declines in some species are to be arrested or reversed, conservation effort will need to focus much more strongly on understanding and managing urban populations, because these might buffer some species against wholesale regional population depletion, particularly where intensive agriculture in the surrounding hinterland has led to declines in bird populations at large. Such a focus will require a significant increase in the priority and resources devoted to conservation activities in urban areas. © 2008 Blackwell Publishing Ltd.
Abstract.
Marini L, Fontana P, Klimek S, Battisti A, Gaston KJ (2009). Impact of farm size and topography on plant and insect diversity of managed grasslands in the Alps.
Biological Conservation,
142(2), 394-403.
Abstract:
Impact of farm size and topography on plant and insect diversity of managed grasslands in the Alps
Since the second half of the 20th century, the intensification of land-use practices and the associated decline in semi-natural habitats have been the major drivers of farmland biodiversity loss. In many marginal agricultural systems, a structural transformation of farms, from small and traditional to large and intensive, has also been observed. We unravelled the impact of farm size and slope on plant, orthopteran and butterfly diversity in 132 hay meadows in a region of the Italian Alps. We defined three farm size classes representing different levels of intensification and used mixed models to test the influence of farm size along with topographic slope. The diversity of plants, orthopterans and butterflies declined with management intensity at the field scale, which mainly depended on farm size and grassland topography. We found a positive effect of slope and a negative influence of farm size on species richness of the three taxonomic groups. Large farms were strongly associated with higher production of organic fertilizers and higher soil fertility than small traditional farms, irrespective of meadow slope. At the regional scale, we found that large farms managed flatter meadows (slope = 9.0) than small traditional farms (slope = 13.5), contributing to the abandonment of steep species-rich grassland areas. Regional stakeholders should consider targeted conservation schemes to prevent the ongoing substitution of small farms with large intensive farms. A complementary solution could be to target future conservation measures to support farms with low production of organic fertilizers and to reward the maintenance of the current management of steep meadows. © 2008 Elsevier Ltd. All rights reserved.
Abstract.
Cianciaruso MV, Batalha MA, Gaston KJ, Petchey OL (2009). Including intraspecific variability in functional diversity.
Ecology,
90(1), 81-89.
Abstract:
Including intraspecific variability in functional diversity
Linking species and ecosystems often relies on approaches that consider how the traits exhibited by species affect ecosystem processes. One method is to estimate functional diversity (FD) based on the dispersion of species in functional trait space. Individuals within a species also differ, however, and an unresolved challenge is how to include such intraspecific variability in a measure of functional diversity. Our solution is to extend an existing measure to variation among individuals within species. Here, simulations demonstrate how the new measure behaves relative to one that does not include individual variation. Individual-level FD was less well associated with species richness than species-level FD in a single trait dimension, because species differed in their intraspecific variation. However, in multiple trait dimensions, there was a strong association between individual-and species-level FD and richness, because many traits result in a tight relationship between functional diversity and species richness. The correlation between the two FD measures weakened as the amount of intraspecific variability increased. Analyzing natural plant communities we found no relationship between species richness and functional diversity. In these analyses, we did not have to specify the source of intraspecific variation. In fact, the variation was only among individuals. The measure can, however, include differences in the amount of intraspecific variation at different sites, as we demonstrate. Including intraspecific variation should allow a more complete understanding of the processes that link individuals and ecosystems and provide better predictions about the consequences of extinctions for ecosystem processes. © 2009 by the Ecological Society of America.
Abstract.
Evans KL, Gaston KJ, Frantz AC, Simeoni M, Sharp SP, McGowan A, Dawson DA, Walasz K, Partecke J, Burke T, et al (2009). Independent colonization of multiple urban centres by a formerly forest specialist bird species.
Proc Biol Sci,
276(1666), 2403-2410.
Abstract:
Independent colonization of multiple urban centres by a formerly forest specialist bird species.
Urban areas are expanding rapidly, but a few native species have successfully colonized them. The processes underlying such colonization events are poorly understood. Using the blackbird Turdus merula, a former forest specialist that is now one of the most common urban birds in its range, we provide the first assessment of two contrasting urban colonization models. First, that urbanization occurred independently. Second, that following initial urbanization, urban-adapted individuals colonized other urban areas in a leapfrog manner. Previous analyses of spatial patterns in the timing of blackbird urbanization, and experimental introductions of urban and rural blackbirds to uncolonized cities, suggest that the leapfrog model is likely to apply. We found that, across the western Palaearctic, urban blackbird populations contain less genetic diversity than rural ones, urban populations are more strongly differentiated from each other than from rural populations and assignment tests support a rural source population for most urban individuals. In combination, these results provide much stronger support for the independent urbanization model than the leapfrog one. If the former model predominates, colonization of multiple urban centres will be particularly difficult when urbanization requires genetic adaptations, having implications for urban species diversity.
Abstract.
Author URL.
Šizling AL, Storch D, Reif J, Gaston KJ (2009). Invariance in species-abundance distributions.
Theoretical Ecology,
2(2), 89-103.
Abstract:
Invariance in species-abundance distributions
Many attempts to explain the species-abundance distribution (SAD) assume that it has a universal functional form which applies to most assemblages. However, if such a form does exist, then it has to be invariant under changes in the area of the study plot (the addition of neighboring areas or subdivision of the original area) and changes in taxonomic composition (the addition of sister taxa or subdivision to subtaxa). We developed a theory for such an area-and-taxon invariant SAD and derived a formula for such a distribution. Both the log-normal and our area-and-taxon invariant distribution fitted data well. However, the log-normal distributions of two adjoined sub-assemblages cannot be composed into a log-normal distribution for the resulting assemblage, and the SAD composed from two log-normal distributions fits the SAD for the assemblage poorly in comparison to the area-and-taxon invariant distribution. Observed abundance patterns therefore reveal area-and-taxon invariant properties absent in log-normal distributions, suggesting that multiplicative models generating log-normal-like SADs (including the power-fraction model) cannot be universally valid, as they necessarily apply only to particular scales and taxa. © Springer Science+Business Media B.V. 2008.
Abstract.
Evans KL, Leech DI, Humphrey QPC, Greenwood J, Gaston KJ (2009). Latitudinal and seasonal patterns in clutch size of some single-brooded British birds.
Bird Study,
56(1), 75-85.
Abstract:
Latitudinal and seasonal patterns in clutch size of some single-brooded British birds
Capsule Daylength, rather than latitude, was found to be an important determinant of variation in clutch size. Aims to describe the nature of spatial and temporal variation in clutch size, and explore the ecological correlates of these patterns. Methods We tested the prediction that seasonal declines in clutch size will be greater at higher latitudes. The environmental variables focused on were the influence of daylength, plant productivity, seasonality (i.e. Ashmole's hypothesis) and physiological mechanisms that relate clutch size to ambient temperature. We used data from 1980 to 2003 on spatial variation in clutch size across Britain for single-brooded species, in which clutch size can be taken as a measure of annual reproductive investment. We included all seven species, from five families, with sufficient data in the British Trust for Ornithology's Nest Record Scheme. Results There are strong seasonal declines in clutch size but little evidence for latitudinal gradients in clutch size or in latitudinal gradients in the rate of seasonal clutch size decline. of the environmental variables investigated, daylength had the most marked effect on clutch size; this was positive in diurnal species and negative in the one nocturnal species. Conclusions Although this study was confined to a relatively small latitudinal range of 8°, we found marked latitudinal gradients in a number of factors thought to drive spatial patterns in clutch size. Moreover, such variation is of sufficient magnitude to generate spatial patterns in other ecological variables in Britain. There is thus no simple explanation for the lack of a latitudinal gradient in clutch size. The results concerning daylength indicate that the time available for foraging is an important determinant of variation in clutch size. © 2009 British Trust for Ornithology.
Abstract.
Gaston KJ, Chown SL, Calosi P, Bernardo J, Bilton DT, Clarke A, Clusella-Trullas S, Ghalambor CK, Konarzewski M, Peck LS, et al (2009). Macrophysiology: a conceptual reunification.
Am Nat,
174(5), 595-612.
Abstract:
Macrophysiology: a conceptual reunification.
Widespread recognition of the importance of biological studies at large spatial and temporal scales, particularly in the face of many of the most pressing issues facing humanity, has fueled the argument that there is a need to reinvigorate such studies in physiological ecology through the establishment of a macrophysiology. Following a period when the fields of ecology and physiological ecology had been regarded as largely synonymous, studies of this kind were relatively commonplace in the first half of the twentieth century. However, such large-scale work subsequently became rather scarce as physiological studies concentrated on the biochemical and molecular mechanisms underlying the capacities and tolerances of species. In some sense, macrophysiology is thus an attempt at a conceptual reunification. In this article, we provide a conceptual framework for the continued development of macrophysiology. We subdivide this framework into three major components: the establishment of macrophysiological patterns, determining the form of those patterns (the very general ways in which they are shaped), and understanding the mechanisms that give rise to them. We suggest ways in which each of these components could be developed usefully.
Abstract.
Author URL.
Mora C, Myers RA, Coll M, Libralato S, Pitcher TJ, Sumaila RU, Zeller D, Watson R, Gaston KJ, Worm B, et al (2009). Management effectiveness of the world's marine fisheries.
PLoS Biology,
7(6).
Abstract:
Management effectiveness of the world's marine fisheries
Ongoing declines in production of the world's fisheries may have serious ecological and socioeconomic consequences. As a result, a number of international efforts have sought to improve management and prevent overexploitation, while helping to maintain biodiversity and a sustainable food supply. Although these initiatives have received broad acceptance, the extent to which corrective measures have been implemented and are effective remains largely unknown. We used a survey approach, validated with empirical data, and enquiries to over 13,000 fisheries experts (of which 1,188 responded) to assess the current effectiveness of fisheries management regimes worldwide; for each of those regimes, we also calculated the probable sustainability of reported catches to determine how management affects fisheries sustainability. Our survey shows that 7% of all coastal states undergo rigorous scientific assessment for the generation of management policies, 1.4% also have a participatory and transparent processes to convert scientific recommendations into policy, and 0.95% also provide for robust mechanisms to ensure the compliance with regulations; none is also free of the effects of excess fishing capacity, subsidies, or access to foreign fishing. A comparison of fisheries management attributes with the sustainability of reported fisheries catches indicated that the conversion of scientific advice into policy, through a participatory and transparent process, is at the core of achieving fisheries sustainability, regardless of other attributes of the fisheries. Our results illustrate the great vulnerability of the world's fisheries and the urgent need to meet well-identified guidelines for sustainable management; they also provide a baseline against which future changes can be quantified. © 2009 Mora et al.
Abstract.
Booth JE, Gaston KJ, Armsworth PR (2009). Public understanding of protected area designation.
Biological Conservation,
142(12), 3196-3200.
Abstract:
Public understanding of protected area designation
Protected areas have a central role to play in educating people about biodiversity and nature conservation. However, there is little evidence regarding how effective public education efforts related to protected areas have been. We used on-site questionnaires at Sites of Special Scientific Interest to determine whether visitors to sites were aware of their protected status. Less than one-third of visitors knew the site they were visiting was a SSSI. However, there was substantial variation in understanding across sites (8-43%). When we compared this variation to five possible predictor variables, only membership of conservation organisations was retained in all models in the 95% confidence set, with members of these groups being better informed about protected area designations. However, the predictive power of all models was low. These results represent a challenge for those aiming to reengage people with conservation and the countryside, and to educate them about its value and contribution. © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Šiding AL, Šizlingová E, Storch D, Reif J, Gaston KJ (2009). Rarity, commonness, and the contribution of individual species to species richness patterns.
American Naturalist,
174(1), 82-93.
Abstract:
Rarity, commonness, and the contribution of individual species to species richness patterns
Common species have a greater effect on observed geographical patterns of species richness than do rare ones. Here we present a theory of the relationship between individual species occurrence patterns and patterns in species richness, which allows purely geometrical and statistical causes to be distinguished from biological ones. Relationships between species occupancy and the correlation of species occurrence with overall species richness are driven by the frequency distribution of species richness among sites. Moreover, generally positive relationships are promoted by the fact that species occupancy distributions are mostly right skewed. However, biological processes can lead to deviations from the predicted pattern by changing the nestedness of a species' spatial distribution with regard to the distributions of other species in an assemblage. We have applied our theory to data for European birds at several spatial scales and have identified the species with significantly stronger or weaker correspondence with the overall richness pattern than that predicted by the null model. In sum, whereas the general macroecological pattern of a stronger influence of common species than of rare species on species richness is predicted by mathematical considerations, the theory can reveal biologically important deviations at the level of individual species. © 2009 by the University of Chicago.
Abstract.
Jackson SF, Walker K, Gaston KJ (2009). Relationship between distributions of threatened plants and protected areas in Britain.
Biological Conservation,
142(7), 1515-1522.
Abstract:
Relationship between distributions of threatened plants and protected areas in Britain
The establishment and maintenance of a system of protected areas is central to regional and global strategies for the conservation of biodiversity. The current global trend towards human population growth and widespread environmental degradation means that such areas are becoming increasingly isolated in fragmented habitat islands. In regions in which this process is well advanced a high proportion of species are thus predicted to have become restricted to protected areas. Here using uniquely detailed datasets for Britain, a region with close to the global level of percentage coverage by statutory protected areas, we determine the extent of restriction of Red List vascular plant species of conservation concern to these areas. On the basis of currently known distributions, overall our results strongly support the importance of a dual conservation strategy in Britain, in which protected areas are maintained with particular reference to those biodiversity features (such as many threatened plant species) that are highly dependent on them, and in which components of the wider landscape are also managed in such a way as to promote the abundance and distribution of such features with particular reference to those which are unlikely to persist in protected areas alone. © 2009 Elsevier Ltd. All rights reserved.
Abstract.
Guilhaumon F, Gimenez O, Gaston KJ, Mouillot D (2009). Reply to Bode and Murdoch: a proper integration of species-area relationship uncertainties into return on investment analyses is needed. Proceedings of the National Academy of Sciences of the United States of America, 106(7).
Marini L, Fontana P, Battisti A, Gaston KJ (2009). Response of orthopteran diversity to abandonment of semi-natural meadows.
Agriculture, Ecosystems and Environment,
132(3-4), 232-236.
Abstract:
Response of orthopteran diversity to abandonment of semi-natural meadows
The response of orthopteran communities to abandonment of extensively managed hay meadows was investigated in an Alpine region. Fifty-five sites in four different successional stages were sampled: (i) mown meadows, (ii) young abandoned meadows, (iii) old abandoned meadows, and (iv) young forests. Mown meadows and young abandoned meadows (3-5 years since the last cut) had the highest, young forests the lowest mean number of orthopteran species. The change in vegetation structure and the shading by woody plants are considered the most important drivers determining the orthopteran diversity response to abandonment. Well-targeted agri-environment schemes are needed to maintain extensive semi-natural hay meadows with the provision of compensation payments to support transitional stages (young and old abandoned meadows). A mowing regime with a supra-annual cycle (e.g. 3-5 years) could be a suitable management practice to reduce direct mortality due to mechanical mowing and to halt forest invasion. © 2009 Elsevier B.V. All rights reserved.
Abstract.
Blackburn TM, Gaston KJ (2009). Sometimes the obvious answer is the right one: a response to 'Missing the rarest: is the positive interspecific abundance-distribution relationship a truly general macroecological pattern?'. Biology Letters, 5(6), 777-778.
Anderson BJ, Armsworth PR, Eigenbrod F, Thomas CD, Gillings S, Heinemeyer A, Roy DB, Gaston KJ (2009). Spatial covariance between biodiversity and other ecosystem service priorities.
Journal of Applied Ecology,
46(4), 888-896.
Abstract:
Spatial covariance between biodiversity and other ecosystem service priorities
Ecosystems support biodiversity and also provide goods and services that are beneficial to humans. The extent to which the locations that are most valuable for ecosystem services coincide with those that support the most biodiversity is of critical importance when designing conservation and land management strategies. There are, however, few studies on which to base any kind of conclusion about possible spatial patterns of association between ecosystem services and biodiversity. Moreover, little is known about the sensitivity of the conclusions to the quality of the data available, or to the choice and size of the region used for analysis. Here, we first present national-scale estimates of the spatial covariance in areas important for ecosystem services and biodiversity (richness of species of conservation concern), using Britain as a case study. We then explore how these associations are sensitive to the spatial resolution of the available data, the spatial extent of our study region and to regional variation across the study area. Our analyses reveal a mixture of negative and positive associations. In particular, the regionalization analysis shows that one can arrive at diametrically opposing conclusions about relationships between ecosystem services and biodiversity by studying the same question within different areas, even within a moderately small island. Synthesis and applications. In a policy context, the location-specific nature of relationships between ecosystem services and biodiversity underscores the importance of multi-scale environmental decision-making, so as to reflect both local conditions and broader-scale priorities. The results also suggest that efforts to establish general patterns of congruence in ecosystem services and biodiversity may offer a less constructive way forward than do more regional approaches. © 2009 British Ecological Society.
Abstract.
Šizling AL, Storch D, Šizlingová E, Reif J, Gaston KJ (2009). Species abundance distribution results from a spatial analogy of central limit theorem.
Proceedings of the National Academy of Sciences of the United States of America,
106(16), 6691-6695.
Abstract:
Species abundance distribution results from a spatial analogy of central limit theorem
The frequency distribution of species abundances [the species abundance distribution (SAD)] is considered to be a fundamental characteristic of community structure. It is almost invariably strongly right-skewed, with most species being rare. There has been much debate as to its exact properties and the processes from which it results. Here, we contend that an SAD for a study plot must be viewed as spliced from the SADs of many smaller nonoverlap-ping subplots covering that plot. We show that this splicing, if applied repeatedly to produce subplots of progressively larger size, leads to the observed shape of the SAD for the whole plot regardless of that of the SADs of those subplots. The widely reported shape of an SAD is thus likely to be driven by a spatial parallel of the central limit theorem, a statistically convergent process through which the SAD arises from small to large scales. Exact properties of the SAD are driven by species spatial turnover and the spatial autocorrelation of abundances, and can be predicted using this information. The theory therefore provides a direct link between SADs and the spatial correlation structure of species distributions, and thus between several fundamental descriptors of community structure. Moreover, the statistical process described may lie behind similar frequency distributions observed in many other scientific fields.
Abstract.
Fishburn IS, Kareiva P, Gaston KJ, Evans KL, Armsworth PR (2009). State-level variation in conservation investment by a major nongovernmental organization.
CONSERVATION LETTERS,
2(2), 74-81.
Author URL.
Jackson SF, Evans KL, Gaston KJ (2009). Statutory protected areas and avian species richness in Britain.
Biodiversity and Conservation,
18(8), 2143-2151.
Abstract:
Statutory protected areas and avian species richness in Britain
An effective portfolio of protected areas should, all else being equal, give rise to positive relationships between the amount of protected land in a region and the numbers of species present. Tests of this prediction are, however, extremely scarce, and most do not control for the potentially confounding effects of environmental factors that influence broad geographic trends in biodiversity. Here, we document the form of the relationship between species richness and coverage by protected areas using the British avifauna as a case study. We contrast relationships that arise for breeding and wintering assemblages, considering both all species collectively and threatened species only. We use spatially explicit multiple regression analyses that take into account environmental factors previously shown to exert a marked influence on avian species richness in Britain (temperature and altitude). Avian species richness and the amount of protected land are consistently positively correlated with each other, and the slopes of these relationships do not differ between assemblages (breeding/wintering and all species/threatened species). Explanatory power is, however, very weak which may be indicative of the ability of conservation measures in the wider landscape to maintain avian species richness, reducing any distinctive influence of protected areas. © Springer Science+Business Media B.V. 2009.
Abstract.
Blackburn TM, Cassey P, Evans KL, Gaston KJ, Duncan RP (2009). The biogeography of avian extinctions on oceanic islands revisited.
Journal of Biogeography,
36(8), 1613-1614.
Abstract:
The biogeography of avian extinctions on oceanic islands revisited
A recent paper by Karels et al. 'The biogeography of avian extinctions on oceanic islands' (Journal of Biogeography, 2008, 35, 1106-1111), uses structural equation modelling to assess the causes of the number of island bird species driven extinct in the historical period. Here, we critically assess the conclusions of the paper and argue that it does not provide the new insights into the causes of extinction in island birds that its authors claim. © 2008 Blackwell Publishing Ltd.
Abstract.
Evans KL, Gaston KJ, Sharp SP, McGowan A, Hatchwell BJ (2009). The effect of urbanisation on avian morphology and latitudinal gradients in body size.
Oikos,
118(2), 251-259.
Abstract:
The effect of urbanisation on avian morphology and latitudinal gradients in body size
Urban areas occupy a large and growing proportion of the earth. Such sites exhibit distinctive characteristics relative to adjacent rural habitats, and many species have colonised and now successfully exploit urban habitats. The change in selection pressures as a result of urbanisation has led to trait divergence in some urban populations relative to their rural counterparts, but studies have generally been local in scale and the generality of differentiation thus remains unknown. The European blackbird Turdus merula is one of the commonest urban bird species in the Western Palearctic, but populations vary substantially in the length of time they have been urbanised. Here we investigate patterns of morphological variation in European blackbirds occupying 11 paired urban and rural habitats across much of the urbanised range of this species and spanning 25° of latitude. First, we assessed the extent to which urban and rural blackbirds are differentiated morphologically and the consistency of any differentiation across the range. Paired urban and rural Blackbird populations frequently exhibited significant morphological differences, but the magnitude and direction of differentiation was site dependent. We then investigated whether the nature of latitudinal gradients in body-size differed between urban and rural populations, as predicted by differences in the climatic regimes of urban and rural areas. Blackbird body-size exhibited strong latitudinal gradients, but their form did not differ significantly between urban and rural habitats. The latitudinal gradient in body size may be a consequence of Seebohm's rule, that more migratory populations occurring at high latitudes have longer wings. We conclude that while there can be substantial morphological variation between adjacent urban and rural bird populations, such differentiation may not apply across a species' range. Locality specific differentiation of urban and rural blackbirds may arise if the selection pressures acting on blackbird morphology vary in an inconsistent manner between urban and rural habitats. Alternatively, phenotypic divergence could arise in a stochastic manner depending on the morphological traits of colonists, through founder effects. © 2009 the Authors.
Abstract.
Fishburn IS, Kareiva P, Gaston KJ, Armsworth PR (2009). The growth of easements as a conservation tool.
PLoS One,
4(3).
Abstract:
The growth of easements as a conservation tool.
BACKGROUND: the numerous studies examining where efforts to conserve biodiversity should be targeted are not matched by comparable research efforts addressing how conservation investments should be structured and what balance of conservation approaches works best in what contexts. An obvious starting point is to examine the past allocation of effort among conservation approaches and how this has evolved. METHODOLOGY/PRINCIPAL FINDINGS: We examine the past allocation of conservation investment between conservation easements and fee simple acquisitions using the largest land trust in operation, the Nature Conservancy (TNC), as a case study. We analyse the balance of investments across the whole of the US and in individual states when measured in terms of the area protected and upfront cost of protecting land. CONCLUSIONS/SIGNIFICANCE: Across the US as a whole, the proportion of conservation investment allocated to easements is growing exponentially. Already 70% of the area of land protected in a given year, and half of all the financial investment in land conservation, is allocated to easements. The growth rate of conservation easements varies by a factor of two across states when measured in terms of the area protected and by a factor of three in terms of financial expenditure. Yet, we were unable to find consistent predictors that explained this variation. Our results underscore the urgency of implementing best practice guidelines for designing easements and of initiating a wider discussion of what balance of conservation approaches is desirable.
Abstract.
Author URL.
Fuller RA, Gaston KJ (2009). The scaling of green space coverage in European cities.
Biology Letters,
5(3), 352-355.
Abstract:
The scaling of green space coverage in European cities
Most people on the planet live in dense aggregations, and policy directives emphasize green areas within cities to ameliorate some of the problems of urban living. Benefits of urban green spaces range from physical and psychological health to social cohesion, ecosystem service provision and biodiversity conservation. Green space coverage differs enormously among cities, yet little is known about the correlates or geography of this variation. This is important because urbanization is accelerating and the consequences for green space are unclear. Here, we use standardized major axis regression to explore the relationships between urban green space coverage, city area and population size across 386 European cities. We show that green space coverage increases more rapidly than city area, yet declines only weakly as human population density increases. Thus, green space provision within a city is primarily related to city area rather than the number of inhabitants that it serves, or a simple space-filling effect. Thus, compact cities (small size and high density) show very low per capita green space allocation. However, at high levels of urbanicity, the green space network is robust to further city compaction. As cities grow, interactions between people and nature depend increasingly on landscape quality outside formal green space networks, such as street plantings, or the size, composition and management of backyards and gardens. © 2009 the Royal Society.
Abstract.
Gaston KJ, Fuller RA (2009). The sizes of species' geographic ranges.
Journal of Applied Ecology,
46(1), 1-9.
Abstract:
The sizes of species' geographic ranges
1. Geographic range size and how it changes through time is one of the fundamental ecological and evolutionary characteristics of a species, and a strong predictor of extinction risk. However, the measurement of range size remains a substantial challenge. Indeed, there is significant confusion in the literature as to how this should be done, particularly in the context of the distinction between the fundamentally different concepts of extent of occurrence (EOO) and area of occupancy (AOO), and the use of these quantities, including in assessments of the threat status of species. 2. Here we review the different approaches to determining the geographic distributions of species, the measurement of their range sizes, the relationships between the two, and other difficulties posed by range size measurement (especially those of range discontinuities when measuring EOO, and spatial scale when measuring AOO). 3. We argue that it is important to (i) distinguish the estimation of the distribution of a species from the measurement of its geographic range size; (ii) treat measures of EOO and AOO as serving different purposes, rather than regarding them as more or less accurate ways of measuring range size; and (iii) measure EOO including discontinuities in habitat or occupancy. 4. Synthesis and applications. With the availability and collation of extensive data sets on species occurrences, a rapidly increasing number of studies are investigating geographic range size, and particularly how various measures of range size predict macroecological patterns and inform assessments of the conservation status of species and areas. The distinction between EOO and AOO is becoming blurred in many contexts, but most particularly in that of threatened species assessments for Red Listing. Continued progress in these fields demands greater clarity in the meaning and derivation of measures of geographic range size. The two principal measures serve different purposes, and should not be regarded as alternatives that simply differ in accuracy. © 2008 the Authors.
Abstract.
Dallimer M, Acs S, Hanley N, Wilson P, Gaston KJ, Armsworth PR (2009). What explains property-level variation in avian diversity? an inter-disciplinary approach.
Journal of Applied Ecology,
46(3), 647-656.
Abstract:
What explains property-level variation in avian diversity? an inter-disciplinary approach
1. Modern farmed landscapes have witnessed substantial losses in biodiversity principally driven by the ecological changes associated with agricultural intensification. The causes of declines are often well described, but current management practices seem unlikely to deliver the EU-wide policy objective of halting biodiversity losses. 2. Available evidence suggests that property-scale factors can be influential in shaping patterns of biodiversity; however, they are rarely included in studies. Using 44 upland farms in the Peak District, northern England, we investigate the roles of ecological, agricultural and socio-economic factors in determining avian species richness, for the first time incorporating information from all three influences. 3. Although we might expect that habitat quality would be the main factor affecting species richness, these variables had little influence. The landscape context of each property was unimportant in explaining any of the three measures of species richness (Total, Upland and Conservation Concern) used here. Within-property habitat quality did explain 42% of the variation in richness of upland specialist species, but had no influence on Total or Conservation Concern Richness. 4. Socio-economic circumstances of farms alone accounted for 24% of the variation in Total Richness, with land tenure and labour inputs important predictors of avian diversity. However, net income, rental value and the level of Agri-Environment Scheme (AES) payments did not play a role in predicting species richness. 5. Farm management variables, including many of the main prescriptions outlined in AES, accounted for 23% of the variation in the richness of species of Conservation Concern, but less than 10% for Total Richness. However, no farm management variable alone was shown to offer better predictive power of avian species richness than random. 6. Synthesis and applications. The agricultural landscape is managed by a mosaic of landowners, all of whom can influence biodiversity conservation. We demonstrate that variation at the property-scale in habitat, management and socio-economics can feed into determining patterns of biodiversity. Currently, farmland conservation policy largely assumes that socio-economic barriers and financial costs of implementing conservation measures are constant. Incorporating a consideration of the varying circumstances of individual properties into policy design is likely to result in substantial biodiversity gains. © 2008 British Ecological Society.
Abstract.
Sims V, Evans KL, Newson SE, Tratalos JA, Gaston KJ (2008). Avian assemblage structure and domestic cat densities in urban environments.
Diversity and Distributions,
14(2), 387-399.
Abstract:
Avian assemblage structure and domestic cat densities in urban environments
While there is intense debate regarding the impact of domestic cat populations on wildlife, its resolution is hindered by the lack of quite basic information. Domestic cats are generalist and obligate predators that receive supplementary food, and their population density reflects that of humans more than the density of their prey. In such a predator-prey system there is the potential for cat populations to have negative impacts on avian assemblages, which may be indicated by negative correlations between cat density and avian species richness and density. Here we report on the nature of such correlations across urban areas in Britain both for groups of species classified regarding their vulnerability to cat predation and individual species. Taking the availability of green space into account, we find negative relationships between cat densities and the number of bird species breeding in urban 1 km × 1 km squares. These relationships are particularly strong among groups of species that are vulnerable to cat predation. We find positive correlations between cat and avian densities; these have low explanatory power and shallow slopes among the species groups that are particularly vulnerable to cat predation. Evidence that the densities of individual species that are vulnerable to cat predation are negatively correlated with cat densities is equivocal, with at least half the species showing no marked pattern, and the remainder exhibiting contrasting patterns. Our results appear not to be confounded by the density of nest-predating corvids (carrion crow, magpie, and jay), as the density of these species was not strongly negatively correlated with avian species richness or density. The general lack of marked negative correlations between cat and avian densities at our focal spatial scale may be a consequence of consistently high cat densities in our study areas (minimum density is 132 cats per square kilometre), and thus uniformly high impacts of cat populations on urban avian assemblages. © 2007 the Authors.
Abstract.
Gaston KJ (2008). Biodiversity and extinction: the dynamics of geographic range size. Progress in Physical Geography, 32(6), 678-683.
Gaston KJ (2008). Biodiversity and extinction: the importance of being common. Progress in Physical Geography, 32(1), 73-79.
Gaston KJ (2008). Bliodiversity and extinction: the importance of being common.
PROGRESS IN PHYSICAL GEOGRAPHY-EARTH AND ENVIRONMENT,
32(1), 73-79.
Author URL.
Davies RG, Barbosa O, Fuller RA, Tratalos J, Burke N, Lewis D, Warren PH, Gaston KJ (2008). City-wide relationships between green spaces, urban land use and topography.
Urban Ecosystems,
11(3), 269-287.
Abstract:
City-wide relationships between green spaces, urban land use and topography
The growing proportion of human populations living in urban areas, and consequent trends of increasing urban expansion and densification fuel a need to understand how urban form and land use affect environmental quality, including the availability of urban green spaces. Here we use Sheffield as a case study of city-wide relationships between urban green space extent, quality (vegetation cover and tree-cover), and gradients in urban form and topography. The total area of buildings and length of the road network are equally strong negative predictors of extent of green space, while the former predictor is a more important negative influence upon green space quality. Elevation positively influences extent of green space but negatively influences tree-cover. In contrast, slope of terrain positively influences green space quality and is the best predictor of tree-cover. Overall housing density is a more important negative predictor of extent of green space and tree-cover than the densities of individual housing types. Nevertheless, the latter are more important influences upon levels of vegetation cover. Threshold effects of densities of different housing types suggest opportunities for optimising green space quality, with implications for housing policy. Variation in ecological quality of green space may partly reflect different historical intensities of industrial activity. © 2008 Springer Science+Business Media, LLC.
Abstract.
Gaston KJ, Fuller RA (2008). Commonness, population depletion and conservation biology.
Trends Ecol Evol,
23(1), 14-19.
Abstract:
Commonness, population depletion and conservation biology.
Species conservation practice, as opposed to principle, generally emphasizes species at risk of imminent extinction. This results in priority lists principally of those with small populations and/or geographical ranges. However, recent work emphasizes the importance of common species to ecosystems. Even relatively small proportional declines in their abundance can result in large absolute losses of individuals and biomass, occurrences significantly disrupting ecosystem structure, function and services. Here, we argue that combined with evidence of dramatic declines in once common species, this suggests the need to pay more attention to such depletions. Complementing the focus on extinction risk, we highlight important implications for conservation, including the need to identify, monitor and alleviate significant depletion events.
Abstract.
Author URL.
Gaston KJ, Chown SL, Evans KL (2008). Ecogeographical rules: Elements of a synthesis.
Journal of Biogeography,
35(3), 483-500.
Abstract:
Ecogeographical rules: Elements of a synthesis
The development of a more synthetic approach to understanding spatial patterns in biogeography, particularly of the way in which these patterns interact, constitutes a major challenge for the field. Here we propose some key elements of such a synthesis for what can broadly be termed 'ecogeographical rules', that is spatial patterns in biological traits. These include understanding: (1) the different kinds of patterns (intraspecific, interspecific and assemblage), and the distinctions between them; (2) the unifying role that geographical ranges play in linking the patterns together; (3) that this unification can be obscured by the methodological assumptions made in documenting some patterns (e.g. assuming that intraspecific variation does not significantly influence interspecific and assemblage patterns in traits); (4) the implications of other methodological issues for the nature of observed patterns (e.g. how ranges are located on positional or environmental axes for interspecific patterns); (5) the need for further development of models linking different types of traits; (6) the nature of the generality of documented patterns at all levels, and particularly the difference between the frequency with which patterns are documented in the literature and the variety of extant species; and (7) the constraints that the form of intraspecific patterns place on interspecific and assemblage patterns, and that interspecific patterns place on assemblage patterns. © 2007 the Authors.
Abstract.
Greve M, Gaston KJ, Van Rensburg BJ, Chown SL (2008). Environmental factors, regional body size distributions and spatial variation in body size of local avian assemblages.
Global Ecology and Biogeography,
17(4), 514-523.
Abstract:
Environmental factors, regional body size distributions and spatial variation in body size of local avian assemblages
Aim: to determine how well variation in median body size of avian assemblages is predicted by (1) the environmental models usually employed in analyses of Bergmann's rule and (2) random sampling from the regional body size frequency distribution. If body size frequency distributions of local assemblages represent a random sample of a regional frequency distribution, then geographical variation in body sizes of assemblages might be a consequence of the determinants of spatial variation in species richness rather than direct influences on body size per se. Location: Southern Africa. Methods: Median body masses (as a measure of body size) of avian assemblages were calculated for quarter-degree grid cells across South Africa and Lesotho. The relationship between median body mass and four environmental variables (minimum and maximum monthly temperatures, precipitation and seasonality in the normalized difference vegetation index, as a measure of seasonality in productivity) was examined using general linear models first without taking spatial autocorrelation into account, and then accounting for it by fitting an exponential spatial covariance structure. Model fit was assessed using the Akaike information criterion and Akaike weights. At each species richness value, random assemblages were sampled by either drawing species randomly from the regional body mass frequency distribution, or drawing species from the regional body mass frequency distribution with a probability proportional to their geographical distribution in the area. The ability of randomizations to predict actual body masses was examined using two-tailed Fisher exact tests. Results: Seasonality in productivity was the only environmental variable that remained a significant predictor of body mass variation in spatially explicit models, though the positive relationship was weak. When species richness was included in the models it remained the only significant predictor of size variation. Randomizations predicted median body mass poorly at low species richness, but well at high richness. Main conclusions: Environmental models that have previously been proposed explain little of the variation in body mass across avian assemblages in South Africa. However, much of the variation in the median mass of assemblages could be predicted by randomly drawing species from the regional body mass frequency distribution, particularly using randomizations in which all species were drawn from the regional body mass frequency distribution with equal probability and at high species richness values. This outcome emphasizes the need to consider null expectations in investigations of the geographical variation in body size together with the probable environmental mechanisms underlying spatial variation in average size. Moreover, it suggests that in the South African avifauna, spatial variation in the body sizes of assemblages may be determined indirectly by the factors that influence geographical variation in species richness. © 2008 the Author Journal compilation © 2008 Blackwell Publishing.
Abstract.
Sutherland WJ, Bailey MJ, Bainbridge IP, Brereton T, Dick JTA, Drewitt J, Dulvy NK, Dusic NR, Freckleton RP, Gaston KJ, et al (2008). Future novel threats and opportunities facing UK biodiversity identified by horizon scanning.
Journal of Applied Ecology,
45(3), 821-833.
Abstract:
Future novel threats and opportunities facing UK biodiversity identified by horizon scanning
1. Horizon scanning is an essential tool for environmental scientists if they are to contribute to the evidence base for Government, its agencies and other decision makers to devise and implement environmental policies. The implication of not foreseeing issues that are foreseeable is illustrated by the contentious responses to genetically modified herbicide-tolerant crops in the UK, and by challenges surrounding biofuels, foot and mouth disease, avian influenza and climate change. 2. A total of 35 representatives from organizations involved in environmental policy, academia, scientific journalism and horizon scanning were asked to use wide consultation to identify the future novel or step changes in threats to, and opportunities for, biodiversity that might arise in the UK up to 2050, but that had not been important in the recent past. At least 452 people were consulted. 3. Cases for 195 submitted issues were distributed to all participants for comments and additions. All issues were scored (probability, hazard, novelty and overall score) prior to a 2-day workshop. Shortlisting to 41 issues and then the final 25 issues, together with refinement of these issues, took place at the workshop during another two rounds of discussion and scoring. 4. We provide summaries of the 25 shortlisted issues and outline the research needs. 5. We suggest that horizon scanning incorporating wide consultation with providers and users of environmental science is used by environmental policy makers and researchers. This can be used to identify gaps in knowledge and policy, and to identify future key issues for biodiversity, including those arising from outside the domains of ecology and biodiversity. 6. Synthesis and applications. Horizon scanning can be used by environmental policy makers and researchers to identify gaps in knowledge and policy. Drawing on the experience, expertise and research of policy advisors, academics and journalists, this exercise helps set the agenda for policy, practice and research. © 2008 the Authors.
Abstract.
Fuller RA, Warren PH, Armsworth PR, Barbosa O, Gaston KJ (2008). Garden bird feeding predicts the structure of urban avian assemblages.
Diversity and Distributions,
14(1), 131-137.
Abstract:
Garden bird feeding predicts the structure of urban avian assemblages
Households across the developed world cumulatively spend many millions of dollars annually on feeding garden birds. While beneficial effects on avian assemblages are frequently claimed, the relationships between levels of garden bird feeding and local avian populations are unknown. Using data from a large UK city, we show that both avian species richness and abundance vary across different socioeconomic neighbourhood types. We examined whether patterns in bird feeding could explain this variation. The density of bird feeding stations across the urban environment was strongly positively related to avian abundance, after controlling for differences in habitat availability. This effect was almost exclusively driven by the abundance of those species known to utilize garden feeding stations frequently. In contrast, the density of feeding stations had no effect on avian species richness. We also examined variation in the proportion of households in different communities that provide food for birds, a factor that is not correlated with feeder density. The prevalence of bird feeding across different neighbourhoods declined as socioeconomic deprivation increased, and increased with avian species richness and abundance. Our results suggest that the provision of supplementary food for birds by multiple landowners across a city can impact the status of urban bird populations. The potential for harnessing these actions for conservation needs to be explored. © 2007 the Authors.
Abstract.
Jackson SF, Gaston KJ (2008). Incorporating private lands in conservation planning: protected areas in Britain.
Ecol Appl,
18(4), 1050-1060.
Abstract:
Incorporating private lands in conservation planning: protected areas in Britain.
Evaluations of the effectiveness of protected areas often report their inadequate representation of regional variation in environmental conditions, land cover, and biological diversity. One frequent contributory explanation is the heavy reliance placed upon the designation of public as opposed to private lands for statutory protection. Given that protected area designation in Britain has no such constraint, and indeed that more than half of such areas are on private lands, we tested the a priori assumption that within this region the representation of environmental conditions and land cover within statutory protected areas would be more equitable. Despite the reduction in land ownership constraints on where protected areas can be established, a marked bias in protected area coverage remains. Protected areas in Britain tend toward regions of higher elevation, soils of lower economic potential, and coastal/estuarine habitat and fail adequately to represent areas of lower elevation and woodland habitats. Improving the current situation requires not only a more systematic approach to site selection, but a more equitable and diverse portfolio of incentives for private landowners to facilitate the decision to manage sites for conservation.
Abstract.
Author URL.
Jackson SF, Gaston KJ (2008). Land use change and the dependence of national priority species on protected areas.
Global Change Biology,
14(9), 2132-2138.
Abstract:
Land use change and the dependence of national priority species on protected areas
The establishment and maintenance of a system of protected areas is central to regional and global strategies for the conservation of biodiversity. The current global trend towards human population growth and widespread environmental degradation means that such areas are becoming increasingly isolated, fragmented habitat islands. In regions in which this process is well advanced, a high proportion of species are thus predicted to have become restricted to protected areas. Here, using uniquely detailed datasets for Britain, a region with close to the global level of percentage coverage by statutory protected areas, we determine the extent of restriction of species of conservation concern to these areas. On the basis of currently known distributions, more than a half of such species are highly dependent on protected areas for their continued persistence, occurring either entirely or largely within their bounds. Such coverage is of particular importance for those species with narrower distributions, and therefore, under the greatest threats, underlining the vital importance of adequately resourcing, maintaining, and developing protected areas to prevent these species from being lost. © Journal compilation © 2008 Blackwell Publishing.
Abstract.
Chown SL, Gaston KJ (2008). Macrophysiology for a changing world.
Proceedings of the Royal Society B: Biological Sciences,
275(1642), 1469-1478.
Abstract:
Macrophysiology for a changing world
The Millennium Ecosystem Assessment (MA) has identified climate change, habitat destruction, invasive species, overexploitation and pollution as the major drivers of biodiversity loss and sources of concern for human well-being. Understanding how these drivers operate and interact and how they might be mitigated are among the most pressing questions facing humanity. Here, we show how macrophysiology-the investigation of variation in physiological traits over large geographical, temporal and phylogenetic scales-can contribute significantly to answering these questions. We do so by demonstrating, for each of the MA drivers, how a macrophysiological approach can or has helped elucidate the impacts of these drivers and their interactions. Moreover, we illustrate that a large-scale physiological perspective can provide insights into previously unrecognized threats to diversity, such as the erosion of physiological variation and stress tolerance, which are a consequence of the removal of large species and individuals from the biosphere. In so doing we demonstrate that environmental physiologists have much to offer the scientific quest to resolve major environmental problems. © 2008 the Royal Society.
Abstract.
Gaston KJ, Jackson SF, Nagy A, Cantú-Salazar L, Johnson M (2008). Protected areas in Europe: principle and practice.
Ann N Y Acad Sci,
1134, 97-119.
Abstract:
Protected areas in Europe: principle and practice.
Systematic conservation planning provides a structured, target-driven approach to ensuring the long-term maintenance of biodiversity. However, reviews of how well the steps of such a planning process are applied in different regions are scant; some steps may be implemented although there is no formal systematic conservation planning process taking place. Here we conduct such a review for Europe. Taking in turn the six recognized steps of systematic conservation planning, for this region: (i) the availability of data on biodiversity remains a significant constraint on conservation planning because, although species occurrences have often been better mapped in Europe than elsewhere, there is a continuing mismatch between the spatial resolution at which data coverage is adequate and that of habitat fragmentation. (ii) Although there are important legal frameworks for conservation planning, explicit quantitative goals for the representation and persistence of biodiversity are largely lacking. (iii) Assessment of the effectiveness of existing protected area systems is patchy and rather ill developed, with a substantial gulf between the work being conducted in more academic and policy-oriented arenas. (iv) Nonetheless, particularly through the Natura 2000 process, there has been an extraordinary program to select additional protected areas. (v) Although it has taken longer than originally envisaged, this program is resulting in a substantial expansion of the protected area system. (vi) There are significant concerns over the extent to which existing protected area systems can maintain their biodiversity values, particularly given the small size of many of these areas and likely impacts of climate change.
Abstract.
Author URL.
Mace GM, Collar NJ, Gaston KJ, Hilton-Taylor C, Akçakaya HR, Leader-Williams N, Milner-Gulland EJ, Stuart SN (2008). Quantification of extinction risk: IUCN's system for classifying threatened species.
Conservation Biology,
22(6), 1424-1442.
Abstract:
Quantification of extinction risk: IUCN's system for classifying threatened species
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species was increasingly used during the 1980s to assess the conservation status of species for policy and planning purposes. This use stimulated the development of a new set of quantitative criteria for listing species in the categories of threat: critically endangered, endangered, and vulnerable. These criteria, which were intended to be applicable to all species except microorganisms, were part of a broader system for classifying threatened species and were fully implemented by IUCN in 2000. The system and the criteria have been widely used by conservation practitioners and scientists and now underpin one indicator being used to assess the Convention on Biological Diversity 2010 biodiversity target. We describe the process and the technical background to the IUCN Red List system. The criteria refer to fundamental biological processes underlying population decline and extinction. But given major differences between species, the threatening processes affecting them, and the paucity of knowledge relating to most species, the IUCN system had to be both broad and flexible to be applicable to the majority of described species. The system was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size. A species is assigned to a threat category if it meets the quantitative threshold for at least one criterion. The criteria and the accompanying rules and guidelines used by IUCN are intended to increase the consistency, transparency, and validity of its categorization system, but it necessitates some compromises that affect the applicability of the system and the species lists that result. In particular, choices were made over the assessment of uncertainty, poorly known species, depleted species, population decline, restricted ranges, and rarity; all of these affect the way red lists should be viewed and used. Processes related to priority setting and the development of national red lists need to take account of some assumptions in the formulation of the criteria. © 2008 Society for Conservation Biology.
Abstract.
Thomas GH, Orme CDL, Davies RG, Olson VA, Bennett PM, Gaston KJ, Owens IPF, Blackburn TM (2008). Regional variation in the historical components of global avian species richness.
Global Ecology and Biogeography,
17(3), 340-351.
Abstract:
Regional variation in the historical components of global avian species richness
Aim: Using a global data base of the distribution of extant bird species, we examine the evidence for spatial variation in the evolutionary origins of contemporary avian diversity. In particular, we assess the possible role of the timing of mountain uplift in promoting diversification in different regions. Location: Global. Methods: We mapped the distribution of avian richness at four taxonomic levels on an equal-area 1° grid. We examined the relationships between richness at successive taxonomic levels (e.g. species richness vs. genus richness). We mapped the residuals from linear regressions of these relationships to identify areas that are exceptional in the number of lower taxa relative to the number of higher taxa. We use generalized least squares models to test the influence of elevation range and temperature on lower-taxon richness relative to higher-taxon richness. Results: Peaks of species richness in the Neotropics were congruent with patterns of generic richness, whilst peaks in Australia and the Himalayas were congruent with patterns of both genus and family richness. Hotspots in the Afrotropics did not reflect higher-taxon patterns. Regional differences in the relationship between richness at successive taxonomic levels revealed variation in patterns of taxon co-occurrence. Species and genus co-occurrence was positively associated with elevational range across much of the world. Taxon occurrence in the Neotropics was associated with a positive interaction between elevational range and temperature. Conclusions: These results demonstrate that contemporary patterns of richness show different associations with higher-taxon richness in different regions, which implies that the timing of historical effects on these contemporary patterns varies across regions. We suggest that this is due to dispersal limitation and phylogenetic constraints on physiological tolerance limits promoting diversification. We speculate that diversification rates respond to long-term changes in the Earth's topography, and that the role of tropical mountain ranges is implicated as a correlate of contemporary diversity, and a source of diversification across avian evolutionary history. © 2008 the Authors Journal compilation © 2008 Blackwell Publishing Ltd.
Abstract.
Evans KL, Newson SE, Storch D, Greenwood JJD, Gaston KJ (2008). Spatial scale, abundance and the species-energy relationship in British birds.
J Anim Ecol,
77(2), 395-405.
Abstract:
Spatial scale, abundance and the species-energy relationship in British birds.
1. The spatial scale of analysis may influence the nature, strength and underlying drivers of macroecological patterns, one of the most frequently discussed of which is the relationship between species richness and environmental energy availability. 2. It has been suggested that species-energy relationships are hump-shaped at fine spatial grains and consistently positive at larger regional grains. The exact nature of this scale dependency is, however, the subject of much debate as relatively few studies have investigated species-energy relationships for the same assemblage across a range of spatial grains. Here, we contrast species-energy relationships for the British breeding avifauna at spatial grains of 1 km x 1 km, 2 km x 2 km and 10 km x 10 km plots, while maintaining a constant spatial extent. 3. Analyses were principally conducted using data on observed species richness. While survey work may fail to detect some species, observed species richness and that estimated using nonparametric techniques were strongly positively correlated with each other, and thus exhibit very similar spatial patterns. Moreover, the forms of species-energy relationships using observed and estimated species richness were statistically indistinguishable from each other. 4. Positive decelerating species-energy relationships arise at all three spatial grains. There is little evidence that the explanatory power of these relationships varies with spatial scale. However, ratios of regional (large-scale) to local (small-scale) species richness decrease with increasing energy availability, indicating that local richness responds to energy with a steeper gradient than does regional richness. Local assemblages thus sample a greater proportion of regional richness at higher energy levels, suggesting that spatial turnover of species richness is lower in high-energy regions. Similarly, a crude measure of temporal turnover, the ratio of cumulative species richness over a 4-year period to species richness in a single year, is lower in high-energy regions. These negative relationships between turnover and energy appear to be causal as both total and mean occupancy per species increases with energy. 5. While total density in 1 km x 1 km plots correlates positively with energy availability, such relationships are very weak for mean density per species. This suggests that the observed association between total abundance and species richness may not be mediated by population extinction rates, as predicted by the more individuals hypothesis. 6. The sampling mechanism suggests that species-energy relationships arise as high-energy areas support a greater number of individuals, and that random allocation of these individuals to local areas from a regional assemblage will generate species-energy relationships. While randomized local species-energy relationships are linear and positive, predicted richness is consistently greater than that observed. The mismatch between the observed and randomized species-energy relationships probably arises as a consequence of the aggregated nature of species distributions. The sampling mechanism, together with species spatial aggregation driven by limited habitat availability, may thus explain the species-energy relationship observed at this spatial scale.
Abstract.
Author URL.
Phillimore AB, Orme CDL, Thomas GH, Blackburn TM, Bennett PM, Gaston KJ, Owens IPF (2008). Sympatric speciation in birds is rare: Insights from range data and simulations.
American Naturalist,
171(5), 646-657.
Abstract:
Sympatric speciation in birds is rare: Insights from range data and simulations
Sympatric speciation is now accepted as theoretically plausible and a likely explanation for divergence in a handful of taxa, but its contribution to large-scale patterns of speciation remains contentious. A major problem is that it is difficult to differentiate between alternate scenarios of geographic speciation when species ranges have shifted substantially in the past. Previous studies have searched for a signal of the geographic mode of speciation by testing for a correlation between time since speciation and range overlap. Here we use simulations to show that the proportion of species showing zero or complete range overlap are more reliable indicators of the geography of speciation than is the correlation between time since speciation and overlap. We then apply these findings to the distributions of 291 pairs of avian sister species. Although 49% of pairs show some overlap in their ranges, our simulations show that this is not surprising under allopatric models of speciation. More revealingly, less than 2% show complete range overlap. Our simulations demonstrate that the observed patterns are most consistent with a model in which allopatric speciation is dominant but in which sympatric speciation is also present and contributes 5% of speciation events. © 2008 by the University of Chicago. All rights reserved.
Abstract.
Guilhaumon F, Gimenez O, Gaston KJ, Mouillot D (2008). Taxonomic and regional uncertainty in species-area relationships and the identification of richness hotspots.
Proceedings of the National Academy of Sciences of the United States of America,
105(40), 15458-15463.
Abstract:
Taxonomic and regional uncertainty in species-area relationships and the identification of richness hotspots
Species-area relationships (SARs) are fundamental to the study of key and high-profile issues in conservation biology and are particularly widely used in establishing the broad patterns of biodiversity that underpin approaches to determining priority areas for biological conservation. Classically, the SAR has been argued in general to conform to a power-law relationship, and this form has been widely assumed in most applications in the field of conservation biology. Here, using nonlinear regressions within an information theoretical model selection framework, we included uncertainty regarding both model selection and parameter estimation in SAR modeling and conducted a global-scale analysis of the form of SARs for vascular plants and major vertebrate groups across 792 terrestrial ecoregions representing almost 97% of Earth's inhabited land. The results revealed a high level of uncertainty in model selection across biomes and taxa, and that the power-law model is clearly the most appropriate in only a minority of cases. Incorporating this uncertainty into a hotspots analysis using multimodel SARs led to the identification of a dramatically different set of global richness hotspots than when the power-law SAR was assumed. Our findings suggest that the results of analyses that assume a power-law model may be at severe odds with real ecological patterns, raising significant concerns for conservation priority-setting schemes and biogeographical studies. © 2008 by the National Academy of Sciences of the USA.
Abstract.
Gaston KJ, Jackson SF, Cantú-Salazar L, Cruz-Piñón G (2008). The ecological performance of protected areas.
Annual Review of Ecology, Evolution, and Systematics,
39, 93-113.
Abstract:
The ecological performance of protected areas
Protected areas are a cornerstone of local, regional, and global strategies for the conservation of biodiversity. However, the ecological performance of these areas, both in terms of the representation and the maintenance of key biodiversity features, remains poorly understood. A large and rapidly expanding literature bears on these issues, but it is highly fragmented, principally comprises particular case studies, and employs a diverse array of approaches. Here we provide a synthetic review of this work, discriminating between issues of performance of inventory and condition at the scale of individual protected areas, portfolios, and networks of protected areas. We emphasize the insights that follow and the links between the different issues, as well as highlight the major problems that remain unresolved. Copyright © 2008 by Annual Reviews. All rights reserved.
Abstract.
Storch D, Šizling AL, Reif J, Polechová J, Šizlingová E, Gaston KJ (2008). The quest for a null model for macroecological patterns: Geometry of species distributions at multiple spatial scales.
Ecology Letters,
11(8), 771-784.
Abstract:
The quest for a null model for macroecological patterns: Geometry of species distributions at multiple spatial scales
There have been several attempts to build a unified framework for macroecological patterns. However, these have mostly been based either on questionable assumptions or have had to be parameterized to obtain realistic predictions. Here, we propose a new model explicitly considering patterns of aggregated species distributions on multiple spatial scales, the property which lies behind all spatial macroecological patterns, using the idea we term 'generalized fractals'. Species' spatial distributions were modelled by a random hierarchical process in which the original 'habitat' patches were randomly replaced by sets of smaller patches nested within them, and the statistical properties of modelled species assemblages were compared with macroecological patterns in observed bird data. Without parameterization based on observed patterns, this simple model predicts realistic patterns of species abundance, distribution and diversity, including fractal-like spatial distributions, the frequency distribution of species occupancies/abundances and the species-area relationship. Although observed macroecological patterns may differ in some quantitative properties, our concept of random hierarchical aggregation can be considered as an appropriate null model of fundamental macroecological patterns which can potentially be modified to accommodate ecologically important variables. © 2008 Blackwell Publishing Ltd/CNRS.
Abstract.
Jackson SF, Gaston KJ (2008). The unpredictability of favourability: Condition assessment and protected areas in England.
Biodiversity and Conservation,
17(4), 749-764.
Abstract:
The unpredictability of favourability: Condition assessment and protected areas in England
The probability that protected areas will deliver their potential for maintaining or enhancing biodiversity is likely to be maximised if they are appropriately and effectively managed. As a result, governments and conservation agencies are devoting much attention to the management of protected areas. In the U.K. the demand for performance accountability has resulted in Public Service Agreements (PSA) that set out targets for government departments to deliver results in return for investments being made. One such target for England is to ensure that all nationally important wildlife sites are in favourable condition by 2010. Here, we tested the hypothesis, of potential strategic importance, that the ecological condition of these sites is predictable from relationships with a range of physical, environmental and demographic variables. We used binary logistic regression to investigate these relationships, using the results of English Nature's 1997-2003 condition assessment exercise. Generally, sites in unfavourable condition tend to be larger in area, located at higher elevations, but with higher human population density and are more spatially isolated from units of the same habitat. However, despite the range of different parameters included in our models, the extent to which the condition of any given site could be predicted was low. Our results have implications for the delivery of PSA targets, funding allocation, and the location of new protected areas. © 2007 Springer Science+Business Media B.V.
Abstract.
Blackburn TM, Cassey P, Duncan RP, Evans KL, Gaston KJ (2008). Threats to avifauna on oceanic islands revisited. Conservation Biology, 22(2), 492-494.
Loram A, Thompson K, Warren PH, Gaston KJ (2008). Urban domestic gardens (XII): the richness and composition of the flora in five UK cities.
Journal of Vegetation Science,
19(3), 321-330.
Abstract:
Urban domestic gardens (XII): the richness and composition of the flora in five UK cities
Question: What floras are typically associated with domestic gardens in cities? Location: the urban areas of the cities of Belfast, Cardiff, Edinburgh, Leicester and Oxford, UK. Methods: the composition and diversity of plant species in 267 urban domestic gardens in the five cities was recorded by complete census and quadrat sampling. Results: the entire garden flora consisted of 1056 species, of which 30% were native and 70% alien. 34% of the 50 most frequently recorded species in gardens were native, a number of them being weeds. Although plant species richness in individual gardens varied with garden area, the above breakdowns held true when the cities were considered individually. The only exception was Belfast where, overall, plant species richness was slightly lower than in any of the other cities. Comparing quadrat samples, species richness was found to be greater in the garden habitats of each of the cities than in a number of other habitats, with species accumulation curves showing no sign of reaching saturation at 120 quadrats. This is due to the high proportion of alien species found in gardens, and in particular those surviving at low densities as a result of human intervention. Conclusion: There was surprisingly little difference in plant species richness, diversity or composition between the cities, despite the variation in geographical and climatic factors. This suggests that human factors such as plant availability, garden management and social/economic status of individual householders had an overriding influence. © IAVS; Opulus Press Uppsala.
Abstract.
Loram A, Warren PH, Gaston KJ (2008). Urban domestic gardens (XIV): the characteristics of gardens in five cities.
Environ Manage,
42(3), 361-376.
Abstract:
Urban domestic gardens (XIV): the characteristics of gardens in five cities.
Domestic gardens make substantial contributions to the provision of green space in urban areas. However, the ecological functions provided by such gardens depend critically on their configuration and composition. Here, we present the first detailed analysis of variation in the composition of urban gardens, in relation to housing characteristics and the nature of the surrounding landscape, across different cities in the United Kingdom. In all five cities studied (Belfast, Cardiff, Edinburgh, Leicester, and Oxford), garden size had an overwhelming influence on garden composition. Larger gardens supported more of the land-use types recorded, in greater extents, and were more likely to contain particular features, including tall trees and mature shrubs, areas of unmown grass and uncultivated land, vegetable patches, ponds, and composting sites. The proportional contribution of non-vegetated land-uses decreased as garden area increased. House age was less significant in determining the land-use within gardens, although older houses, which were more likely to be found further from the urban edge of the city, contained fewer hedges and greater areas of vegetation canopy >2 m in height. Current UK government planning recommendations will ultimately reduce the area of individual gardens and are thus predicted to result in fewer tall trees and, in particular, less vegetation canopy >2 m. This might be detrimental from ecological, aesthetic, social, and economic stand points.
Abstract.
Author URL.
Newson SE, Evans KL, Noble DG, Greenwood JJD, Gaston KJ (2008). Use of distance sampling to improve estimates of national population sizes for common and widespread breeding birds in the UK.
Journal of Applied Ecology,
45(5), 1330-1338.
Abstract:
Use of distance sampling to improve estimates of national population sizes for common and widespread breeding birds in the UK
1. Population estimates are of fundamental importance for setting conservation priorities and for numerous aspects of conservation biology. 2. Distance sampling, which takes undetected individuals into account, is one of the most widely used methods for generating population estimates. We use this method to generate estimates of the national population size for all common and widespread non-marine breeding birds in the UK using Breeding Bird Survey data. 3. There is a strong positive relationship between our distance-sampled estimates and estimates generated using other methods. This implies that most methods get the broad picture right, even if one of them is less precise for individual species. 4. For some species, detectability may vary sufficiently between males and females to generate biases in population size estimates if these differences are not taken into account. We found a slight tendency for population estimates from distance sampling to be lower than existing estimates for species with marked sex biases in detectability. This may be a wider problem than is currently acknowledged in distance sampling. 5. Distance sampling provides a method for estimating total population size. Other bird population survey methods, such as intensive territory mapping, aim to count the number of breeding pairs, and thus exclude non-breeding individuals. Not surprisingly, we found that distance-sampled estimates tended to be higher for species with a large proportion of non-breeders. Both approaches are valid, but when calculating, reporting and using population estimates attention needs to be paid to which variable is of most interest. 6. The new estimates that we present are significantly larger than existing ones for species whose preferred habitat types were not previously well surveyed. This highlights the importance of sampling across all main habitat types. 7. Synthesis and applications. This study reviews alternative methods used for producing estimates of population size for common and widespread breeding birds in the UK. We assess a number of factors affecting population estimates generated by distance sampling. © 2008 the Authors.
Abstract.
Gaston KJ, Fuller RA (2007). Biodiversity and extinction: Losing the common and the widespread. Progress in Physical Geography, 31(2), 213-225.
Phillimore AB, Orme CDL, Davies RG, Hadfield JD, Reed WJ, Gaston KJ, Freckleton RP, Owens IPF (2007). Biogeographical basis of recent phenotypic divergence among birds: a global study of subspecies richness.
Evolution,
61(4), 942-957.
Abstract:
Biogeographical basis of recent phenotypic divergence among birds: a global study of subspecies richness
Theory predicts that biogeographic factors should play a central role in promoting population divergence and speciation. Previous empirical studies into biogeography and diversification have been relatively restricted in terms of the geographical area, phylogenetic scope, and the range of biogeographic factors considered. Here we present a global analysis of allopatric phenotypic divergence (measured as subspecies richness) across more than 9600 bird species. The main aim of this study was to examine the extent to which biogeographical factors can explain patterns of phenotypic divergence. Analysis of the taxonomic distribution of subspecies among species suggests that subspecies formation and extinction have occurred at a considerably faster rate than has species formation. However, the observed distribution departs from the expectation under a random birth-death model of diversification. Across 19 phylogenetic trees, we find no significant linear relationship between species age and subspecies richness, implying that species age is a poor predictor of subspecies richness. Both subspecies richness and subspecies diversification rate are found to exhibit low phylogenetic signal, meaning that closely related species do not tend to possess similar numbers of subspecies. As predicted by theory, high subspecies richness was associated with large breeding range size, island dwelling, inhabitation of montane regions, habitat heterogeneity, and low latitude. of these factors, breeding range size was the variable that explained the most variation. Unravelling whether species that have invaded previously glacial areas have more or fewer subspecies than expected proves to be complicated due to a covariation between the postglacial colonization, latitude, geographic range size, and subspecies richness. However, the effect of postglacial colonization on subspecies richness appears to be small. Mapping the distribution of species' subspecies richness globally reveals geographical patterns that correspond to many of the predictions of the statistical models, but may also reflect geographical variation in taxonomic practice. Overall, we demonstrate that biogeographic models can explain about 30% of the global variation in subspecies richness in birds. © 2007 the Author(s).
Abstract.
Tratalos J, Fuller RA, Evans KL, Davies RG, Newson SE, Greenwood JJD, Gaston KJ (2007). Bird densities are associated with household densities.
Global Change Biology,
13(8), 1685-1695.
Abstract:
Bird densities are associated with household densities
Increasing housing density is an important component of global land transformation, with major impacts on patterns of biodiversity. However, while there have been many studies of the changes in biodiversity across rural-urban gradients, which are influenced in large part by housing densities, how biodiversity changes across the full range of regional variation in housing density remains poorly understood. Here, we explore these relationships for the richness and abundance of breeding birds across Britain. Total richness, and that of 27 urban indicator species, increased from low to moderate household densities and then declined at greater household densities. The richness of all species increased initially faster with household density than did that of the urban indicator species, but nonurban indicator species richness declined consistently after peaking at a very low housing density. Avian abundance showed a rather different pattern. Total abundance and that summed across all urban indicator species increased over a wide range of household densities, and declined only at the highest household densities. The abundance of individual urban indicator species generally exhibited a hump-shaped relationship with housing density. While there was marked intraspecific variation in the form of such relationships, almost invariably avian abundance declined at housing densities below that at which the UK government requires new developments to be built. Our data highlight the difficulties of maintaining biodiversity while minimising land take for new development. High-density housing developments are associated with declines in many of those species otherwise best able to exploit urban environments, and those components of native biodiversity with which human populations are often most familiar. © 2007 Blackwell Publishing Ltd.
Abstract.
Fuller RA, Warren PH, Gaston KJ (2007). Daytime noise predicts nocturnal singing in urban robins.
Biol Lett,
3(4), 368-370.
Abstract:
Daytime noise predicts nocturnal singing in urban robins.
Ambient noise interferes with the propagation of acoustic signals through the environment from sender to receiver. Over the past few centuries, urbanization and the development of busy transport networks have led to dramatic increases in the levels of ambient noise with which animal acoustic communications must compete. Here we show that urban European robins Erithacus rubecula, highly territorial birds reliant on vocal communication, reduce acoustic interference by singing during the night in areas that are noisy during the day. The effect of ambient light pollution, to which nocturnal singing in urban birds is frequently attributed, is much weaker than that of daytime noise.
Abstract.
Author URL.
Petchey OL, Gaston KJ (2007). Dendrograms and measuring functional diversity.
Oikos,
116(8), 1422-1426.
Abstract:
Dendrograms and measuring functional diversity
Patterns and changes in functional diversity can inform about spatial and temporal variation in trait diversity, about the processes that drive assembly, and whether assemblages are likely to contain redundant species. We recently provided a new measure (termed FD) and detailed its advantages over previous ones. Since then an increasing amount of research effort has been directed towards both developing appropriate measures of functional diversity and critiquing previous ones, including FD. Podani and Schmera (2006) attempt to do both, though here we argue that they accomplish neither. First, they suggest that a particular distance measure and clustering method are appropriate. We suggest that this is not the case, and show that they may have little effect on quantitative patterns in FD. Second, they suggest that values of functional diversity must be insensitive to the number of functional traits used. We do not agree because we can envisage no relevant ecological question. Third, they observe that we originally defined an FD of zero for an empty assemblage, whereas it is more appropriate for single species assemblages to have FD of zero. We agree. Their solution, however, is to create a measure of functional diversity which violates set monotonicity. Our solution is a revised version of FD for which single species assemblages have FD=0, and which does not violate set monotonicity. In conclusion, we are confident that FD behaves appropriately and note that it remains the measure of functional diversity with greatest power to explain variation in ecosystem functioning. © Oikos.
Abstract.
Grenyer R, Orme CDL, Davies TJ, Jackson SF, Davies RG, Olson VA, Jones KE, Gaston KJ, Blackburn TM, Thomas GH, et al (2007). Effective global conservation strategies - Reply.
NATURE,
450(7171), E20-E20.
Author URL.
Davies RG, Orme CDL, Webster AJ, Jones KE, Blackburn TM, Gaston KJ (2007). Environmental predictors of global parrot (Aves: Psittaciformes) species richness and phylogenetic diversity.
Global Ecology and Biogeography,
16(2), 220-233.
Abstract:
Environmental predictors of global parrot (Aves: Psittaciformes) species richness and phylogenetic diversity
Aim: Spatial patterns of phylogenetic diversity (PD) aid our ability to discern diversification rate mechanisms underlying hypotheses for the large-scale distribution of biodiversity. We develop a predictive framework for the way in which spatial patterns of PD vary with those of species richness, depending on the balance between speciation and extinction rates. Within this framework, diversification processes thought to underlie the productive energy, ambient energy, topographic variability and habitat variety hypotheses predict that gradients of increase in species richness will be associated with: (1) decreasing extinction rates where driven by productive energy, hence increasing relative PD (i.e. PD controlling for species richness, or PDrel); (2) a similar positive relationship between ambient energy and PDrel; (3) increasing speciation rates where driven by topographic variability, hence decreasing PDrel; and (4) no consistent relationship between PDrel and habitat variety when driven by the latter. We test these predictions using distributional data on parrots. Location: Neotropical, Afrotropical, Indo-Malayan and Australasian realms. Methods: Spatial models were used to test the predictions. Results: Globally, a positive association between productive energy and PDrel confirms prediction (1). However, within realms, hump-shaped relationships suggest the importance of decreasing extinction rates up to a threshold level of productive energy, and the increasing importance of speciation rates thereafter. Ambient energy is positively associated with PD rel in Australasia, Indo-Malaya, and globally, supporting prediction (2). However, this is driven by the coincidence of highest PDrel in areas of high ambient energy and intermediate productive energy (i.e. in seasonal tropical environments), which may be characterized by relatively low speciation and extinction rates. In the Neotropics, increasing topographic variability is associated with decreasing PDrel and increasing species richness, suggesting an increasing gradient of speciation, supporting prediction (3). Elsewhere, the signal of this mechanism may be obscured by collinearities with energy gradients. The lack of an overall relationship between habitat diversity and PDrelconfirms prediction (4). Main conclusions: Spatial patterns of PDrel in relation to environmental gradients may be sensitive to collinearities among those gradients. Nevertheless, patterns emerge which have implications for the relative importance of speciation and extinction processes in generating latitudinal diversity gradients. © 2007 the Authors Journal compilation © 2007 Blackwell Publishing Ltd.
Abstract.
He F, Gaston KJ (2007). Estimating abundance from occurrence: an underdetermined problem. American Naturalist, 170(4), 655-659.
Bebber DP, Harris SA, Gaston KJ, Scotland RW (2007). Ethnobotany and the first printed records of British flowering plants.
Global Ecology and Biogeography,
16(1), 103-108.
Abstract:
Ethnobotany and the first printed records of British flowering plants
Aim: to determine the relative influence of medicinal use, height and geographical range on the chronological sequence of the first verifiable printed records of 1239 native species of flowering plants in the UK. Location: UK. Methods: We used Cox proportional hazards models to provide a direct estimate of the influence through time of explanatory variables on the hazard function. Results: in the period from 1538 to 1550, medicinal plants were 5-15 (95% confidence interval) times more likely to be discovered than non-medicinal plants. By 1600, 75% of medicinal plants had been discovered, and subsequently medicinal use had no significant influence on the probability of discovery. From 1538 to 1983, a 100-hectad increase in area resulted in a 4-6% increase in the probability of discovery. There was a small but significant decrease in the influence of area on the probability of discovery over the entire time period. In the same time period, a 10-fold increase in height resulted in a 3-35% increased probability of discovery. Main conclusions: Our results demonstrate that the first written records (1538-1600) of UK flowering plants were very strongly influenced by the perceived medicinal properties of the plants. © 2006 the Authors Journal compilation © 2006 Blackwell Publishing Ltd.
Abstract.
Mouillot D, Gaston KJ (2007). Geographical range size heritability: What do neutral models with different modes of speciation predict?.
Global Ecology and Biogeography,
16(3), 367-380.
Abstract:
Geographical range size heritability: What do neutral models with different modes of speciation predict?
Aim: Phylogenetic conservatism or heritability of the geographical range sizes of species (i.e. the tendency for closely related species to share similar range sizes) has been predicted to occur because of the strong phylogenetic conservatism of niche traits. However, the extent of such heritability in range size is disputed and the role of biology in shaping this attribute remains unclear. Here, we investigate the level of heritability of geographical range sizes that is generated from neutral models assuming no biological differences between species. Methods: We used three different neutral models, which differ in their speciation mode, to simulate the life-history of 250,000 individuals in a square lattice of 50 × 50 cells. These individuals can speciate, reproduce, migrate and die in the metacommunity according to stochastic events. We ran each model for 3000 steps and recorded the range size of each species at each step. The heritability of geographical range size was assessed using an asymmetry coefficient between range sizes of sister species and using the coefficient of correlation between the range sizes of ancestors and their descendants. Results: Our results demonstrated the ability of neutral models to mimic some important observed patterns in the heritability of geographical range size. Consistently, sister species exhibited higher asymmetry in range sizes than expected by chance, and correlations between the range sizes of ancestor-descendant species pairs, although often weak, were almost invariably positive. Main conclusions: Our findings suggest that, even without any biological trait differences, statistically significant heritability in the geographical range sizes of species can be found. This heritability is weaker than that observed in some empirical studies, but suggests that even here a substantial component of heritability may not necessarily be associated with niche conservatism. We also conclude that both present-day and fossil data sets may provide similar information on the heritability of the geographical range sizes of species, while the omission of rare species will tend to overestimate this heritability. © 2007 the Authors Journal compilation © 2007 Blackwell Publishing Ltd.
Abstract.
Grenyer R, Orme CDL, Davies TJ, Jackson SF, Davies RG, Olson VA, Jones KE, Gaston KJ, Blackburn TM, Thomas GH, et al (2007). Grenyer et al. reply. Nature, 450(7171).
Gaston KJ, Cush P, Ferguson S, Frost P, Gaston S, Knight D, Loram A, Smith RM, Thompson K, Warren PH, et al (2007). Improving the contribution of urban gardens for wildlife: Some guiding propositions. British Wildlife, 18(3), 171-177.
Gaston KJ (2007). Latitudinal gradient in species richness.
Curr Biol,
17(15).
Author URL.
Fuller RJ, Gaston KJ, Quine CP (2007). Living on the edge: British and Irish woodland birds in a European context.
Ibis,
149(SUPPL. 2), 53-63.
Abstract:
Living on the edge: British and Irish woodland birds in a European context
This paper reviews broad geographical patterns in the species composition of breeding woodland bird communities from Ireland to eastern Europe and outlines how processes affecting woodland birds in Britain and Ireland may differ from those operating in mainland Europe. Bird communities in British and Irish woodlands consist of a subset of the species occurring within European forests at similar latitudes. The occurrence of virtually all groups of forest birds is lower in Britain, and strikingly lower in Ireland, than in other temperate areas of mainland Europe. This phenomenon appears to form part of a west-east gradient in species diversity and is probably not just a consequence of insularity. Across this gradient there appears to be broad geographical constancy in the types (taxonomic, ecological and life-history groups) of species present. There is considerable spatial variation in habitat use by forest species within Europe. Some species in Britain probably use habitats in different ways to elsewhere for reasons related to competition, predation and historical adaptation to landscape change. Several species appear to reach the limits of their geographical ranges within Britain (i.e. in the absence of physical barriers). We suggest that range contraction of one of these species, the Common Nightingale Luscinia megarhynchos, in Britain may partially reflect redistribution into the highest quality areas in response to a wider population decline. It is argued that conclusions drawn from studies of forest birds in Britain do not necessarily apply in other regions and vice versa. There is a need for large-scale studies in Europe of the spatial variation in organization of forest bird assemblages, habitat use and the genetic structure of populations. © 2007 the Authors.
Abstract.
Petchey OL, Evans KL, Fishburn IS, Gaston KJ (2007). Low functional diversity and no redundancy in British avian assemblages.
J Anim Ecol,
76(5), 977-985.
Abstract:
Low functional diversity and no redundancy in British avian assemblages.
1. Spatial and temporal patterns in functional diversity can reveal the patterns and processes behind community assembly and whether ecological redundancy exists. Here, we analyse functional diversity in British avian assemblages over a period of about 20 years. 2. Functional diversity is generally lower than expected by chance, indicating that assemblages contain species with relatively similar functional traits. One potential explanation is filtering for traits suitable to particular habitats, though other explanations exist. 3. There was no evidence of ecological redundancy over the 20 years. In fact, changes in functional diversity were almost exactly proportional to changes in species richness. 4. The absence of functional redundancy results from little redundancy intrinsic to the species' functional relationships and also because compositional change was nonrandom. Observed extinction and colonization events caused greater changes in functional diversity than if these events were random. 5. Our findings suggest that community assembly is influenced by the traits of species and that observed changes in functional diversity provide no reason to believe that the functioning of natural systems is buffered against change by ecological redundancy.
Abstract.
Author URL.
Bebber DP, Marriott FHC, Gaston KJ, Harris SA, Scotland RW (2007). Predicting unknown species numbers using discovery curves.
Proceedings of the Royal Society B: Biological Sciences,
274(1618), 1651-1658.
Abstract:
Predicting unknown species numbers using discovery curves
A common approach to estimating the total number of extant species in a taxonomic group is to extrapolate from the temporal pattern of known species descriptions. A formal statistical approach to this problem is provided. The approach is applied to a number of global datasets for birds, ants, mosses, lycophytes, monilophytes (ferns and horsetails), gymnosperms and also to New World grasses and UK flowering plants. Overall, our results suggest that unless the inventory of a group is nearly complete, estimating the total number of species is associated with very large margins of error. The strong influence of unpredictable variations in the discovery process on species accumulation curves makes these data unreliable in estimating total species numbers. © 2007 the Royal Society.
Abstract.
Fuller RA, Irvine KN, Devine-Wright P, Warren PH, Gaston KJ (2007). Psychological benefits of greenspace increase with biodiversity.
Biol Lett,
3(4), 390-394.
Abstract:
Psychological benefits of greenspace increase with biodiversity.
The world's human population is becoming concentrated into cities, giving rise to concerns that it is becoming increasingly isolated from nature. Urban public greenspaces form the arena of many people's daily contact with nature and such contact has measurable physical and psychological benefits. Here we show that these psychological benefits increase with the species richness of urban greenspaces. Moreover, we demonstrate that greenspace users can more or less accurately perceive species richness depending on the taxonomic group in question. These results indicate that successful management of urban greenspaces should emphasize biological complexity to enhance human well-being in addition to biodiversity conservation.
Abstract.
Author URL.
Evans KL, Lennon JJ, Gaston KJ (2007). Slopes of Avian Species-Area Relationships, Human Population Density, and Environmental Factors.
AVIAN CONSERVATION AND ECOLOGY,
2(2).
Author URL.
Gaston KJ, Davies RG, Orme CDL, Olson VA, Thomas GH, Ding T-S, Rasmussen PC, Lennon JJ, Bennett PM, Owens IPF, et al (2007). Spatial turnover in the global avifauna.
Proc Biol Sci,
274(1618), 1567-1574.
Abstract:
Spatial turnover in the global avifauna.
Despite its wide implications for many ecological issues, the global pattern of spatial turnover in the occurrence of species has been little studied, unlike the global pattern of species richness. Here, using a database on the breeding distributions of birds, we present the first global maps of variation in spatial turnover for an entire taxonomic class, a pattern that has to date remained largely a matter of conjecture, based on theoretical expectations and extrapolation of inconsistent patterns from different biogeographic realms. We use these maps to test four predictions from niche theory as to the form that this variation should take, namely that turnover should increase with species richness, towards lower latitudes, and with the steepness of environmental gradients and that variation in turnover is determined principally by rare (restricted) species. Contrary to prediction, we show that turnover is high both in areas of extremely low and high species richness, does not increase strongly towards the tropics, and is related both to average environmental conditions and spatial variation in those conditions. These results are closely associated with a further important and novel finding, namely that global patterns of spatial turnover are driven principally by widespread species rather than the restricted ones. This complements recent demonstrations that spatial patterns of species richness are also driven principally by widespread species, and thus provides an important contribution towards a unified model of how terrestrial biodiversity varies both within and between the Earth's major land masses.
Abstract.
Author URL.
Evans KL, Greenwood JJD, Gaston KJ (2007). The positive correlation between avian species richness and human population density in Britain is not attributable to sampling bias.
Global Ecology and Biogeography,
16(3), 300-304.
Abstract:
The positive correlation between avian species richness and human population density in Britain is not attributable to sampling bias
Aim: to assess whether spatial variation in sampling effort drives positive correlations between human population density and species richness. Location: British 10 × 10 km squares. Methods: We calculated three measures of species richness from atlas data of breeding birds in Britain: total species richness, species richness standardised for sampling effort, and the number of species only recorded in supplementary casual records in a manner not standardised for survey effort. We then assessed the form of the relationship between these richness estimates and human population density, both with and without taking spatial autocorrelation into account. Results: Both total and standardised species richness exhibit similar species richness-human population density relationships; species richness generally increases with human population density, but decreases at the very highest densities. Supplementary species richness is very weakly correlated with human population density. Main conclusions: in this example, sampling effort only slightly influences the form of species richness-human population density relationships. The positive correlation between species richness and human population density and any resultant conservation conflicts are thus not artefactual patterns generated by confounding human density and sampling effort. © 2007 the Authors Journal compilation © 2007 Blackwell Publishing Ltd.
Abstract.
Davies RG, Orme CDL, Storch D, Olson VA, Thomas GH, Ross SG, Ding T-S, Rasmussen PC, Bennett PM, Owens IPF, et al (2007). Topography, energy and the global distribution of bird species richness.
Proc Biol Sci,
274(1614), 1189-1197.
Abstract:
Topography, energy and the global distribution of bird species richness.
A major goal of ecology is to determine the causes of the latitudinal gradient in global distribution of species richness. Current evidence points to either energy availability or habitat heterogeneity as the most likely environmental drivers in terrestrial systems, but their relative importance is controversial in the absence of analyses of global (rather than continental or regional) extent. Here we use data on the global distribution of extant continental and continental island bird species to test the explanatory power of energy availability and habitat heterogeneity while simultaneously addressing issues of spatial resolution, spatial autocorrelation, geometric constraints upon species' range dynamics, and the impact of human populations and historical glacial ice-cover. At the finest resolution (1 degree), topographical variability and temperature are identified as the most important global predictors of avian species richness in multi-predictor models. Topographical variability is most important in single-predictor models, followed by productive energy. Adjusting for null expectations based on geometric constraints on species richness improves overall model fit but has negligible impact on tests of environmental predictors. Conclusions concerning the relative importance of environmental predictors of species richness cannot be extrapolated from one biogeographic realm to others or the globe. Rather a global perspective confirms the primary importance of mountain ranges in high-energy areas.
Abstract.
Author URL.
Beckerman AP, Boots M, Gaston KJ (2007). Urban bird declines and the fear of cats.
ANIMAL CONSERVATION,
10(3), 320-325.
Author URL.
Loram A, Tratalos J, Warren PH, Gaston KJ (2007). Urban domestic gardens (X): the extent & structure of the resource in five major cities.
Landscape Ecology,
22(4), 601-615.
Abstract:
Urban domestic gardens (X): the extent & structure of the resource in five major cities
Private domestic gardens are known to constitute a considerable proportion of "green space" in urban areas and are therefore of potential significance for maintaining biodiversity and ecosystem service provision in such areas. However, little is known about the actual size and nature of this resource. This study provides the first detailed audit and comparison of the size and structure of the domestic garden resource across different cities in the U.K. (Edinburgh, Belfast, Leicester, Oxford and Cardiff). The urban area of each city covered by domestic gardens ranged from 21.8% to 26.8% and was positively correlated with variation in human population density and housing density. In a random sample of at least 500 houses in each city, 99% had associated gardens, the mean areas of which ranged from 155.4 m2 to 253.0 m2 and were closely associated with housing type (terraced, semi-detached or detached houses). Relatively small gardens (< 400 m 2) contributed disproportionately to the total garden area of each city, being more numerous than larger gardens. There was no clear relationship between garden area and distance to the edge of any of the cities. These and other results are discussed in terms of the potential role of urban gardens as wildlife habitats and the implications for housing policy. © 2007 Springer Science+Business Media, Inc.
Abstract.
Gaston KJ, Fuller RA, Loram A, MacDonald C, Power S, Dempsey N (2007). Urban domestic gardens (XI): Variation in urban wildlife gardening in the United Kingdom.
Biodiversity and Conservation,
16(11), 3227-3238.
Abstract:
Urban domestic gardens (XI): Variation in urban wildlife gardening in the United Kingdom
Two consequences of the continued urbanisation of the human population are that a growing proportion of the landscape is less hospitable to, and that a growing proportion of people are disconnected from, native biodiversity. One response of the UK government has been to establish a goal, and an associated baseline indicator, of increasing the extent and range of public participation in gardening for wildlife. The formulation of policy to attain this end requires, however, insight into the factors that are associated with the level of participation. Here we examine the relationships, across 15 areas in five UK cities, between the proportion of households providing various garden features for wildlife or participating in various wildlife gardening activities, and housing densities and characteristics of the garden resource. We show that significant numbers of households participate in some form of wildlife gardening, but that the predominant form this participation takes is feeding wild birds. Key variables associated with spatial variation in wildlife gardening activities are the proportion of households with access to a garden and, more importantly, average garden size and the proportion of land cover by gardens. There was no evidence for strong effects of household density or the socio-economic status of householders on the prevalence of wildlife friendly features in gardens or on the participation by householders in activities to encourage wildlife. Our results suggest important considerations in attempts to increase awareness and participation in wildlife gardening. © 2007 Springer Science+Business Media, Inc.
Abstract.
Tratalos J, Fuller RA, Warren PH, Davies RG, Gaston KJ (2007). Urban form, biodiversity potential and ecosystem services.
Landscape and Urban Planning,
83(4), 308-317.
Abstract:
Urban form, biodiversity potential and ecosystem services
Using data from selected areas in five UK cities, we studied the relationships between urban form and the following measures of ecosystem performance: availability and patch characteristics of tree cover, gardens and green space; storm-water run-off; maximum temperature; carbon sequestration. Although most measures of ecosystem performance declined with increasing urban density, there was considerable variability in the relationships. This suggests that at any given density, there is substantial scope for maximising ecological performance. The social status of residents was related to measures of tree cover. Housing type was significantly associated with some types of ecosystem service provision, indicating that the type of development may be important independent of its density. These findings have implications for understanding the distribution of ecosystem services and biodiversity across urban landscapes, and the management of development aimed at meeting UK government housing density targets. © 2007 Elsevier B.V. All rights reserved.
Abstract.
Barbosa O, Tratalos JA, Armsworth PR, Davies RG, Fuller RA, Johnson P, Gaston KJ (2007). Who benefits from access to green space? a case study from Sheffield, UK.
Landscape and Urban Planning,
83(2-3), 187-195.
Abstract:
Who benefits from access to green space? a case study from Sheffield, UK
Green spaces play a crucial role in supporting urban ecological and social systems, a fact recognised in public policy commitments in both the UK and Europe. The amount of provision, the distribution of green space and the ease of access to such spaces are key contributors to social and ecological function in urban environments. We measured distance along the transport network to public green space available to households in Sheffield, and compared this with the distribution of private garden space. In addition, we used a geodemographic database, Mosaic UK, to examine how access to green space varies across different sectors of society. Public green spaces are chronically underprovided relative to recommended targets. For example, 64% of Sheffield households fail to meet the recommendation of the regulatory agency English Nature (EN), that people should live no further than 300 m from their nearest green space. Moreover, this figure rises to 72% if we restrict attention to municipal parks recognised by the local council. There is an overall reduction in coverage by green space when moving from neighbourhoods where green space is primarily publicly provided to those where it is privately provided. While access to public green space varies significantly across different social groups, those enjoying the greatest access include more deprived groups and older people. This study highlights the need for additional green space to be created and existing green space to be protected in light of increasing development pressure. © 2007 Elsevier B.V. All rights reserved.
Abstract.
Pautasso M, Gaston KJ (2006). A test of the mechanisms behind avian generalized individuals-area relationships.
Global Ecology and Biogeography,
15(3), 303-317.
Abstract:
A test of the mechanisms behind avian generalized individuals-area relationships
Aim: Questions related to abundances of organisms are central to ecological research. A priori, a scale independent estimation of abundances would be expected. However, we find estimates of numbers of bird individuals from all over the world to increase less than proportionately with increasing plot size. At the whole assemblage level, the pattern holds across biogeographical regions and habitats. The slope of the interspecific and, for the majority of species, the intraspecific individuals-area relationship is also significantly shallower than 1. The question arises as to which mechanisms cause these patterns. Location: Global. Methods: at the assemblage, interspecific and intraspecific levels, we tested three mechanisms that could be responsible for these patterns by comparing the slope of the individuals-plot area relationship for subsets of a database compiled from the literature. Spatial autocorrelation was controlled for. Results: There was no evidence for an influence of plot area choice in order to sample a constant number of individuals. Evidence for higher survey efficiency was available only with increasing number of visits at the intraspecific level. Evidence for influences of habitat heterogeneity was present at the assemblage, interspecific and intraspecific levels. This mechanism can work only if small plots are delimited non-randomly in homogeneous habitat. Main conclusions: Avian population size estimates without indication of the area over which they were obtained are of substantially less value than those coupled with that information. Ecologists planning to compare avian abundances between plots varying in some other factor of interest should minimize variations in their areas and/or account for them in data analyses. Population viability analyses, regional and global population size estimates, site prioritization and the scaling of ecosystem and species energy utilization need to address the plot area effect on assemblage and individual species abundances. © 2006 Blackwell Publishing Ltd.
Abstract.
Gaston KJ, Borges PAV, He F, Gaspar C (2006). Abundance, spatial variance and occupancy: arthropod species distribution in the Azores.
J Anim Ecol,
75(3), 646-656.
Abstract:
Abundance, spatial variance and occupancy: arthropod species distribution in the Azores.
1. The positive abundance-occupancy and abundance-variance relationships are two of the most widely documented patterns in population and community ecology. 2. Recently, a general model has been proposed linking the mean abundance, the spatial variance in abundance, and the occupancy of species. A striking feature of this model is that it consists explicitly of the three variables abundance, variance and occupancy, and no extra parameters are involved. However, little is known about how well the model performs. 3. Here, we show that the abundance-variance-occupancy model fits extremely well to data on the abundance, variance and occupancy of a large number of arthropod species in natural forest patches in the Azores, at three spatial extents, and distinguishing between species of different colonization status. Indeed, virtually all variation about the bivariate abundance-occupancy and abundance-variance relationships is effectively explained by the third missing variable (variance in abundance in the case of the abundance-occupancy relationship, and occupancy in the case of the abundance-variance relationship). 4. Introduced species tend to exhibit lower densities, less spatial variance in these densities, and occupy fewer sites than native and endemic species. None the less, they all lie on the same bivariate abundance-occupancy and abundance-variance, and trivariate abundance-variance-occupancy, relationships. 5. Density, spatial variance in density, and occupancy appear to be all the things one needs to know to describe much of the spatial distribution of species.
Abstract.
Author URL.
Evans KL, James NA, Gaston KJ (2006). Abundance, species richness and energy availability in the North American avifauna.
Global Ecology and Biogeography,
15(4), 372-385.
Abstract:
Abundance, species richness and energy availability in the North American avifauna
Aim: to determine how species richness, abundance, biomass, energy use and mean number of individuals per species scale with environmental energy availability in wintering and breeding avian assemblages, and to contrast assemblages of (i) common and rare species and (ii) breeding residents and migrants. To assess whether such patterns are compatible with the 'more individuals hypothesis' (MIH) that high-energy areas are species-rich because they support larger populations that are buffered against extinction. Location: the North American continent (latitudinal range 23.4 °-48.1 °N; longitudinal range 124.2°-68.7° W). Methods: Avian species richness, abundance, biomass and energy use were calculated for 295 Resident Bird Count plots. Environmental energy availability was measured using ambient temperature and the Normalized Difference Vegetation Index (NDVI), a close correlate of plant productivity. Analyses took plot area into account, and were conducted (with and without taking habitat type into account) using general linear models and spatial mixed models. Results: Positive species-energy relationships were exhibited by both wintering and breeding assemblages, but were stronger in the former. The structure of winter assemblages responded more strongly to temperature than NDVI, while breeding assemblages tended to respond more strongly to NDVI. Breeding residents responded to annual measures of energy availability while breeding migrants and the winter assemblage responded more strongly to seasonal measures. In the winter assemblage, rare and common species exhibited species-energy relationships of a similar strength, but common breeding species exhibited a much stronger relationship than rare breeding species. In both breeding and wintering assemblages, abundance, biomass and energy use increased with energy availability and species richness. Energy availability was a poor predictor of the mean number of individuals per species. Main conclusions: the nature of the species-energy relationship varies seasonally and with the manner in which energy availability is measured. Our data suggest that residents are less able to respond to seasonal fluxes in resource availability than long-distance migrants. Increasing species richness and energy availability is associated with increasing numbers of individuals, biomass and energy use. While these observations are compatible with the MIH our data provide only equivocal support for this hypothesis, as the rarest species do not exhibit the strongest species-energy relationships. © 2006 Blackwell Publishing Ltd.
Abstract.
Gaston KJ (2006). Biodiversity and extinction: Macroecological patterns and people. Progress in Physical Geography, 30(2), 258-269.
Clarke A, Gaston KJ (2006). Climate, energy and diversity.
Proc Biol Sci,
273(1599), 2257-2266.
Abstract:
Climate, energy and diversity.
In recent years, a number of species-energy hypotheses have been developed to explain global patterns in plant and animal diversity. These hypotheses frequently fail to distinguish between fundamentally different forms of energy which influence diversity in dissimilar ways. Photosynthetically active radiation (PAR) can be utilized only by plants, though their abundance and growth rate is also greatly influenced by water. The Gibbs free energy (chemical energy) retained in the reduced organic compounds of tissue can be utilized by all heterotrophic organisms. Neither PAR nor chemical energy influences diversity directly. Both, however, influence biomass and/or abundance; diversity may then increase as a result of secondary population dynamic or evolutionary processes. Temperature is not a form of energy, though it is often used loosely by ecologists as a proxy for energy; it does, however, influence the rate of utilization of chemical energy by organisms. It may also influence diversity by allowing a greater range of energetic lifestyles at warmer temperatures (the metabolic niche hypothesis). We conclude that there is no single species/energy mechanism; fundamentally different processes link energy to abundance in plants and animals, and diversity is affected secondarily. If we are to make progress in elucidating these mechanisms, it is important to distinguish climatic effects on species' distribution and abundance from processes linking energy supply to plant and animal diversity.
Abstract.
Author URL.
Webb TJ, Gaston KJ, Hannah L, Woodward FI (2006). Coincident scales of forest feedback on climate and conservation in a diversity hot spot.
Proceedings of the Royal Society B: Biological Sciences,
273(1587), 757-765.
Abstract:
Coincident scales of forest feedback on climate and conservation in a diversity hot spot
The dynamic relationship between vegetation and climate is now widely acknowledged. Climate influences the distribution of vegetation; and through a number of feedback mechanisms vegetation affects climate. This implies that land-use changes such as deforestation will have climatic consequences. However, the spatial scales at which such feedbacks occur remain largely unknown. Here, we use a large database of precipitation and tree cover records for an area of the biodiversity-rich Atlantic forest region in south eastern Brazil to investigate the forest-rainfall feedback at a range of spatial scales from ca 101-104 km2. We show that the strength of the feedback increases up to scales of at least 103 km2, with the climate at a particular locality influenced by the pattern of landcover extending over a large area. Thus, smaller forest fragments, even if well protected, may suffer degradation due to the climate responding to land-use change in the surrounding area. Atlantic forest vertebrate taxa also require large areas of forest to support viable populations. Areas of forest of ca 103 km2 would be large enough to support such populations at the same time as minimizing the risk of climatic feedbacks resulting from deforestation. © 2005 the Royal Society.
Abstract.
Mouillot D, Krasnov BR, Shenbrot GI, Gaston KJ, Poulin R (2006). Conservatism of host specificity in parasites.
Ecography,
29(4), 596-602.
Abstract:
Conservatism of host specificity in parasites
As information becomes available for many groups of organisms a general pattern of phylogenetic conservatism in ecological characters or morphological traits is now widely recognized. Conversely, conservatism of external ecological attributes throughout a lineage is still a contentious theme in ecology. Moreover, the studies exploring this topic have focused on free-living organisms, and have ignored parasites. The main external ecological attribute of parasite species is certainly their host specificity, which is a key determinant of both their range size and local abundance. We address the subject of conservatism and predictability of host specificity using 2 large databases concerning, respectively, ectoparasites and endoparasites. We found a significant positive relationship between the numbers of host species infested by flea sister species. Moreover, this result was consistent whether we used sympatric or allopatric flea species, suggesting no influence of the mode of speciation on this conservatism of specificity. Additionally, our results showed that congeneric helminth species have more similar host taxonomic diversities than expected by chance, although this conservatism is due mostly to trematodes. Whilst there is evidence of conservatism, the moderate levels preclude robust prediction of host specificity for one species based on that of closely related species. © Ecography.
Abstract.
Mora C, Andréfouët S, Costello MJ, Kranenburg C, Rollo A, Veron J, Gaston KJ, Myers RA (2006). Coral reefs and the global network of marine protected areas.
Science,
312(5781), 1750-1751.
Abstract:
Coral reefs and the global network of marine protected areas
Existing marine reserves are largely ineffective and as a whole remain insufficient for the protection of coral reef diversity.
Abstract.
Storch D, Davies RG, Zajíček S, Orme CDL, Olson V, Thomas GH, Ding TS, Rasmussen PC, Ridgely RS, Bennett PM, et al (2006). Energy, range dynamics and global species richness patterns: Reconciling mid-domain effects and environmental determinants of avian diversity.
Ecology Letters,
9(12), 1308-1320.
Abstract:
Energy, range dynamics and global species richness patterns: Reconciling mid-domain effects and environmental determinants of avian diversity
Spatial patterns of species richness follow climatic and environmental variation, but could reflect random dynamics of species ranges (the mid-domain effect, MDE). Using data on the global distribution of birds, we compared predictions based on energy availability (actual evapotranspiration, AET, the best single correlate of avian richness) with those of range dynamics models. MDE operating within the global terrestrial area provides a poor prediction of richness variation, but if it operates separately within traditional biogeographic realms, it explains more global variation in richness than AET. The best predictions, however, are given by a model of global range dynamics modulated by AET, such that the probability of a range spreading into an area is proportional to its AET. This model also accurately predicts the latitudinal variation in species richness and variation of species richness both within and between realms, thus representing a compelling mechanism for the major trends in global biodiversity. © 2006 Blackwell Publishing Ltd/CNRS.
Abstract.
Petchey OL, Gaston KJ (2006). Functional diversity: back to basics and looking forward.
Ecol Lett,
9(6), 741-758.
Abstract:
Functional diversity: back to basics and looking forward.
Functional diversity is a component of biodiversity that generally concerns the range of things that organisms do in communities and ecosystems. Here, we review how functional diversity can explain and predict the impact of organisms on ecosystems and thereby provide a mechanistic link between the two. Critical points in developing predictive measures of functional diversity are the choice of functional traits with which organisms are distinguished, how the diversity of that trait information is summarized into a measure of functional diversity, and that the measures of functional diversity are validated through quantitative analyses and experimental tests. There is a vast amount of trait information available for plant species and a substantial amount for animals. Choosing which traits to include in a particular measure of functional diversity will depend on the specific aims of a particular study. Quantitative methods for choosing traits and for assigning weighting to traits are being developed, but need much more work before we can be confident about trait choice. The number of ways of measuring functional diversity is growing rapidly. We divide them into four main groups. The first, the number of functional groups or types, has significant problems and researchers are more frequently using measures that do not require species to be grouped. of these, some measure diversity by summarizing distances between species in trait space, some by estimating the size of the dendrogram required to describe the difference, and some include information about species' abundances. We show some new and important differences between these, as well as what they indicate about the responses of assemblages to loss of individuals. There is good experimental and analytical evidence that functional diversity can provide a link between organisms and ecosystems but greater validation of measures is required. We suggest that non-significant results have a range of alternate explanations that do not necessarily contradict positive effects of functional diversity. Finally, we suggest areas for development of techniques used to measure functional diversity, highlight some exciting questions that are being addressed using ideas about functional diversity, and suggest some directions for novel research.
Abstract.
Author URL.
Grenyer R, Orme CDL, Jackson SF, Thomas GH, Davies RG, Davies TJ, Jones KE, Olson VA, Ridgely RS, Rasmussen PC, et al (2006). Global distribution and conservation of rare and threatened vertebrates.
Nature,
444(7115), 93-96.
Abstract:
Global distribution and conservation of rare and threatened vertebrates
Global conservation strategies commonly assume that different taxonomic groups show congruent geographical patterns of diversity, and that the distribution of extinction-prone species in one group can therefore act as a surrogate for vulnerable species in other groups when conservation decisions are being made. The validity of these assumptions remains unclear, however, because previous tests have been limited in both geographical and taxonomic extent. Here we use a database on the global distribution of 19,349 living bird, mammal and amphibian species to show that, although the distribution of overall species richness is very similar among these groups, congruence in the distribution of rare and threatened species is markedly lower. Congruence is especially low among the very rarest species. Cross-taxon congruence is also highly scale dependent, being particularly low at the finer spatial resolutions relevant to real protected areas. 'Hotspots of rarity and threat are therefore largely non-overlapping across groups, as are areas chosen to maximize species complementarity. Overall, our results indicate that 'silver-bullet' conservation strategies alone will not deliver efficient conservation solutions. Instead, priority areas for biodiversity conservation must be based on high-resolution data from multiple taxa. ©2006 Nature Publishing Group.
Abstract.
Orme CDL, Davies RG, Olson VA, Thomas GH, Ding TS, Rasmussen PC, Ridgely RS, Stattersfield AJ, Bennett PM, Owens IPF, et al (2006). Global patterns of geographic range size in birds.
PLoS Biology,
4(7), 1276-1283.
Abstract:
Global patterns of geographic range size in birds
Large-scale patterns of spatial variation in species geographic range size are central to many fundamental questions in macroecology and conservation biology. However, the global nature of these patterns has remained contentious, since previous studies have been geographically restricted and/or based on small taxonomic groups. Here, using a database on the breeding distributions of birds, we report the first (to our knowledge) global maps of variation in species range sizes for an entire taxonomic class. We show that range area does not follow a simple latitudinal pattern. Instead, the smallest range areas are attained on islands, in mountainous areas, and largely in the southern hemisphere. In contrast, bird species richness peaks around the equator, and towards higher latitudes. Despite these profoundly different latitudinal patterns, spatially explicit models reveal a weak tendency for areas with high species richness to house species with significantly smaller median range area. Taken together, these results show that for birds many spatial patterns in range size described in geographically restricted analyses do not reflect global rules. It remains to be discovered whether global patterns in geographic range size are best interpreted in terms of geographical variation in species assemblage packing, or in the rates of speciation, extinction, and dispersal that ultimately underlie biodiversity. © 2006 Orme et al.
Abstract.
Mora C, Andrefouet S, Costello MJ, Kranenburg C, Rollo A, Veron J, Gaston KJ, Myers RA (2006). How protected are coral reefs? Response.
SCIENCE,
314(5800), 758-760.
Author URL.
Davies RG, Orme CDL, Olson V, Thomas GH, Ross SG, Ding T-S, Rasmussen PC, Stattersfield AJ, Bennett PM, Blackburn TM, et al (2006). Human impacts and the global distribution of extinction risk.
Proc Biol Sci,
273(1598), 2127-2133.
Abstract:
Human impacts and the global distribution of extinction risk.
Understanding the global geographical distribution of extinction risk is a key challenge in conservation biology. It remains controversial, however, to what extent areas become threat hotspots simply because of high human impacts or due to predisposing ecological conditions. Limits to the taxonomic and geographical extent, resolution and quality of previously available data have precluded a full global assessment of the relative roles of these factors. Here, we use a new global database on the geographical distributions of birds on continents and continental islands to show that, after controlling for species richness, the best predictors of the global pattern of extinction risk are measures of human impact. Ecological gradients are of secondary importance at a global scale. The converse is true for individual biogeographic realms, within which variation in human impact is reduced and its influence on extinction risk globally is therefore underestimated. These results underline the importance of a global perspective on the mechanisms driving spatial patterns of extinction risk, and the key role of anthropogenic factors in driving the current extinction crisis.
Abstract.
Author URL.
Vázquez LB, Gaston KJ (2006). People and mammals in Mexico: Conservation conflicts at a national scale.
Biodiversity and Conservation,
15(8), 2397-2414.
Abstract:
People and mammals in Mexico: Conservation conflicts at a national scale
Contrary to much supposition, recent studies, typically at global and continent-wide scales, have documented a positive relationship between spatial variations in human density and species richness of selected groups of vertebrates. How widely this pattern generalises remains unknown, and particularly how well it extends to analyses at the extent of a country and at reasonably fine spatial resolution, and to regions with well-developed mechanised agricultural infrastructure. Here, we demonstrate that there is a positive relationship between human density and mammal species richness across Mexico, and that this appears to follow from similar patterns between spatial environmental variation (particularly net primary productivity, precipitation and temperature) and both human density and mammal species richness. These results have some potentially important implications for conservation planning in the region, particularly given that optimal complementary sets of areas to represent all mammal species in Mexico tend to lie in areas of disproportionately high human density. © 2005 Springer.
Abstract.
Evans KL, van Rensburg BJ, Gaston KJ, Chown SL (2006). People, species richness and human population growth.
Global Ecology and Biogeography,
15(6), 625-636.
Abstract:
People, species richness and human population growth
Aim: to investigate how the magnitude of conservation conflicts arising from positive relationships between human population size and species richness is altered during a period of marked human population growth (2% year-1). Location: South Africa. Methods: Anuran and avian species richness were calculated from atlas distribution maps, and human population was measured in 1996 and 2001, all at a quarter-degree resolution. We investigated the relationships between human population size in, and its change during, these two periods and environmental energy availability. We then investigated the nature of relationships between species richness and human population size in both time periods, and its change during them; these analyses were conducted both with and without taking environmental energy availability into account. Finally, we investigated the nature of the relationships between human population size, and its change, and the proportion of protected land. Analyses were conducted both without and with taking spatial autocorrelation into account; the latter was achieved using mixed models that fitted a spatial covariance structure to the data. Results: Change in human population size between 1996 and 2001 exhibited marked spatial variation, with both large increases and decreases, but was poorly correlated with environmental energy availability. The nature of the relationship between human population size and environmental energy availability did not, however, exhibit statistically significant differences regardless of whether the former was measured in 1996 or 2001. Similarly, relationships between species richness and human population size did not exhibit significant differences between the two periods. The strengths of the species-human relationships were markedly reduced when energy availability was taken into account. Change in human population size was poorly correlated with species richness. The proportion of protected land was negatively, albeit rather weakly, correlated with human population size in 1996 and 2001, and with its change between these two periods. Main conclusions: Positive species-human relationships arise largely, but not entirely, because both species richness and human population size exhibit similar responses to environmental energy availability. During a period of rapid human population growth, and marked changes in the spatial variation in human population size, positive correlations remained between human population size and both anuran and avian species richness. The slope of these correlations did not, however, alter, and the most species-rich areas are not those with the largest increases in human population. Despite marked population growth, the magnitude of conservation conflicts arising from positive species-human relationships thus appears to have remained largely unchanged. © 2006 the Authors Journal compilation © 2006 Blackwell Publishing Ltd.
Abstract.
Evans KL, Rodrigues ASL, Chown SL, Gaston KJ (2006). Protected areas and regional avian species richness in South Africa.
Biol Lett,
2(2), 184-188.
Abstract:
Protected areas and regional avian species richness in South Africa.
Protected areas are generally regarded as essential for the long-term maintenance of biodiversity. Evidence for their effectiveness in this regard is, however, somewhat equivocal. Here, we document the relationship between the proportion of protected land and species richness in a region, both with and without taking spatial variation in environmental energy availability into account. Using the South African avifauna as a case study, we find that total and threatened species richness exhibit modest increases with the proportion of protected land. While the protected area network should be expanded, it is essential that conservation efforts also focus on maintaining biodiversity in the wider unprotected landscape that supports high species richness.
Abstract.
Author URL.
Mora C, Andréfouët S, Costello MJ, Kranenburg C, Rollo A, Veron J, Gaston KJ, Myers RA (2006). Response [5]. Science, 314(5800), 758-760.
Evans KL, Jackson SF, Greenwood JJD, Gaston KJ (2006). Species traits and the form of individual species-energy relationships.
Proceedings of the Royal Society B: Biological Sciences,
273(1595), 1779-1787.
Abstract:
Species traits and the form of individual species-energy relationships
Environmental energy availability explains much of the spatial variation in species richness at regional scales. While numerous mechanisms that may drive such total species-energy relationships have been identified, knowledge of their relative contributions is scant. Here, we adopt a novel approach to identify these drivers that exploits the composite nature of species richness, i.e. its summation from individual species distributions. We construct individual species-energy relationships (ISERs) for each species in the British breeding avifauna using both solar (temperature) and productive energy metrics (normalized difference vegetation index) as measures of environmental energy availability. We use the slopes of these relationships and the resultant change in deviance, relative to a null model, as measures of their strength and use them as response variables in multiple regressions that use ecological traits as predictors. The commonest species exhibit the strongest ISERs, which is counter to the prediction derived from the more individuals hypothesis. There is no evidence that predatory species have stronger ISERs, which is incompatible with the suggestion that high levels of energy availability increase the length of the food chain allowing larger numbers of predators to exist. We find some evidence that species with narrow niche breadths have stronger ISERs, thus providing one of the few pieces of supportive evidence that high-energy availability promotes species richness by increasing the occurrence of specialist species that use a narrow range of resources. © 2006 the Royal Society.
Abstract.
Gaston KJ, Charman K, Jackson SF, Armsworth PR, Bonn A, Briers RA, Callaghan CSQ, Catchpole R, Hopkins J, Kunin WE, et al (2006). The ecological effectiveness of protected areas: the United Kingdom.
Biological Conservation,
132(1), 76-87.
Abstract:
The ecological effectiveness of protected areas: the United Kingdom
Given the importance placed on protected areas, determining their effectiveness in representing and maintaining biodiversity is a core issue in conservation biology. Nonetheless, frameworks identifying the breadth of issues associated with this effectiveness, and case studies of how well these are understood in particular regions, remain lacking. In this paper, we provide such a framework and an overview of the current state of knowledge of the ecological effectiveness of protected areas in the United Kingdom. Arguably, better data are available to address such issues in this region than anywhere else in the world. Nonetheless, studies remain scarce and have focussed foremost on the, rather narrow, issue of the effectiveness of management actions on individual sites in order to deliver fixed conservation objectives and discharge statutory responsibilities. Some attention has also been paid to how well the regional collection or portfolio of protected areas performs, particularly in capturing biodiversity features. Work on the extent to which protected areas in the United Kingdom form effective functional networks is in its infancy, but initiatives are under development. We identify some of the questions about the effectiveness of protected areas to which answers need to be known at the site, portfolio and network levels, and how significant progress might be achieved in addressing these. © 2006 Elsevier Ltd. All rights reserved.
Abstract.
Blackburn TM, Gaston KJ (2006). There's more to macroecology than meets the eye.
Global Ecology and Biogeography,
15(6), 537-540.
Abstract:
There's more to macroecology than meets the eye
Macroecology sits at the junction of, and can contribute to, the fields of ecology, biogeography, palaeontology and macroevolution, using a broad range of approaches to tackle a diverse set of questions. Here, we argue that there is more to macroecology than mapping, and that while they are potentially useful, maps are insufficient to assess macroecological pattern and process. The true nature of pattern can only be assessed, and competing hypotheses about process can only be disentangled, by adopting a statistical approach, and it is this that has been key to the development of macroecology as a respected and rigorous scientific discipline. © 2006 the Authors Journal compilation © 2006 Blackwell Publishing Ltd.
Abstract.
Smith RM, Thompson K, Hodgson JG, Warren PH, Gaston KJ (2006). Urban domestic gardens (IX): Composition and richness of the vascular plant flora, and implications for native biodiversity.
Biological Conservation,
129(3), 312-322.
Abstract:
Urban domestic gardens (IX): Composition and richness of the vascular plant flora, and implications for native biodiversity
Garden floras interact with native biodiversity by providing resources for wildlife and by acting as a source of non-native species. Understanding the composition and richness of garden floras will help evaluate the relationships between these floras and the wider environment. The composition and richness of vascular plant floras were measured in a stratified sample of 61 urban, domestic gardens in Sheffield, UK, based on complete garden inventories. The entire garden flora contained 1166 species, of which 30% were native and 70% alien. Across gardens, aliens showed lower occupancy than natives, comprising 79% of the species recorded only once. The garden flora contained 146 plant families, which included 72% of the native, naturalised or recurrent casual families recorded in the wild in Britain and Ireland. Gardens contained on average 45% natives, irrespective of garden size. Garden area explained 30% of the variation in species richness within individual gardens. Doubling garden size led to an increase in species richness of 25%. The garden flora comprised 10% annuals, 63% biennial/perennials, 18% shrubs and 8% trees; shrubs were disproportionately composed of alien species. The floras of urban domestic gardens probably form the greatest source of potentially invasive alien plants. However, the plants found in domestic gardens have closer affinities with the uncultivated flora than is often perceived, and their role for wildlife in gardens deserves reassessment. Declines in garden size that result from recommendations on the density of new housing are unlikely to have major consequences for plant richness in gardens. © 2005 Elsevier Ltd. All rights reserved.
Abstract.
Smith RM, Warren PH, Thompson K, Gaston KJ (2006). Urban domestic gardens (VI): Environmental correlates of invertebrate species richness.
Biodiversity and Conservation,
15(8), 2415-2438.
Abstract:
Urban domestic gardens (VI): Environmental correlates of invertebrate species richness
Domestic gardens associated with residential zones form a major component of undeveloped land in towns and cities. Such gardens may play a vital role in maintaining biodiversity in urban areas, but explanations for the variation in the richness of species assemblages in gardens are lacking. We report the results from a case study of 12 invertebrate groups in 61 domestic gardens in the city of Sheffield, UK. The mean number of species within a taxon, recorded per garden, was no greater than 3, 10, and 20 species in litter, pitfall trap and Malaise trap samples, respectively. Relatively speciose groups exhibited high turnover between gardens, with typically 50% of the group occurring only once. In contrast, several species-poor taxa were virtually ubiquitous. Species richness was analysed by multiple regression and hierarchical tree analysis in relation to garden and landscape variables. In general, the two methods of analysis corroborated one another. In total, 22 explanatory variables entered into regression models, although 12 of them only did so once. The amount of variation in species richness explained in models was generally quite high, with the factors involved operating over a range of scales. However, the patterns that emerged were not consistent across taxa. The most important predictors of species richness, of relevance to land use planners, were components of garden vegetation, especially the abundance of trees. Likely reasons for inconsistencies in the relationships are discussed in the context of sampling and species biology. © 2005 Springer.
Abstract.
Smith RM, Gaston KJ, Warren PH, Thompson K (2006). Urban domestic gardens (VIII): Environmental correlates of invertebrate abundance.
Biodiversity and Conservation,
15(8), 2515-2545.
Abstract:
Urban domestic gardens (VIII): Environmental correlates of invertebrate abundance
Domestic gardens associated with residential zones form a major component of vegetated land in towns and cities. Such gardens may play a vital role in maintaining biodiversity in urban areas, but variation in the abundance of organisms in gardens has been little explored. We report the results from a case study of 61 domestic gardens in the city of Sheffield, UK. Across 22 invertebrate groups, the median number of individuals recorded per garden was 49, 178, and 1012 in litter collections, pitfall and Malaise trap samples, respectively. Abundance was analysed by stepwise multiple regression and hierarchical tree analysis in relation to garden and landscape variables. The amount of variation explained in regression models ranged from 4 to 56%, for data based on pitfall and litter samples, and from 16 to 92% for data from Malaise traps. In total, 31 out of 36 explanatory variables entered into stepwise regression models, and 29 of them did so more than once. Although there was strong evidence only for approximately half of such relationships, in these cases the two methods of analysis corroborated one another. General correlates of invertebrate abundance were lacking, and likely reasons for inconsistencies in the relationships are discussed in the context of sampling and species biology. Correlates of the greatest significance occurred at both landscape (e.g. altitude) and garden scales (e.g. area of canopy vegetation). These factors were associated with species richness as well as abundance. © 2006 Springer.
Abstract.
Blackburn TM, Cassey P, Gaston KJ (2006). Variations on a theme: Sources of heterogeneity in the form of the interspecific relationship between abundance and distribution.
Journal of Animal Ecology,
75(6), 1426-1439.
Abstract:
Variations on a theme: Sources of heterogeneity in the form of the interspecific relationship between abundance and distribution
1. A positive interspecific relationship between abundance and distribution is widely considered to be one of the most general patterns in ecology. However, the relationship appears to vary considerably across assemblages, from significant positive to significant negative correlations and all shades in between. 2. This variation has led to the suggestion that the abundance-distribution relationship has multiple forms, with the corollary that different patterns may inform about, or have different, causes. However, this variation has never been formally quantified, nor has it been determined whether the observed variation is indicative of sampling error in estimating a single effect or of real heterogeneity in such relationships. Here, we use the meta-analytical approach to assess variation in abundance-distribution relationships, and to test different hypotheses for it. 3. Analysis of 279 relationships found a mean effect size of 0.655, which was both highly significantly different from zero and indicative of a strong positive association between abundance and distribution. However, effect sizes were highly heterogeneous, supporting the contention that this relationship does indeed have multiple forms. 4. Most notably, relationships vary significantly in strength across realms, with the strongest in the marine and intertidal, intermediate relationships for terrestrial and parasitic assemblages, and the weakest relationships in freshwater systems. Effect sizes in all of the aquatic realms are homogeneous, suggesting that realm is an important source of the heterogeneity observed across all studies. We posit that this may be because the different spatial structure of the environment in each realm affects the opportunity for the dispersal of individuals between sites. 5. Some of the remaining heterogeneity in effect sizes for terrestrial assemblages could be explained by partitioning assemblages by habitat, scale, biogeographical region and taxon, but considerable heterogeneity in effect sizes for terrestrial and parasitic assemblages remained unexplained. © 2006 the Authors.
Abstract.
Gaston KJ (2005). Biodiversity and extinction: Species and people. Progress in Physical Geography, 29(2), 239-247.
Evans KL, Gaston KJ (2005). Can the evolutionary-rates hypothesis explain species-energy relationships?.
Functional Ecology,
19(6), 899-915.
Abstract:
Can the evolutionary-rates hypothesis explain species-energy relationships?
1. There is growing consensus that much of the marked broad-scale spatial variation in species richness is associated with variation in environmental energy availability, but at least nine principal mechanisms have been proposed that may explain these patterns. 2. The evolutionary-rates hypothesis suggests that high environmental energy availability elevates rates of molecular evolution, promoting faster speciation, so that more species occur in high-energy areas because more evolve there. Direct tests of this hypothesis are rare and their conclusions inconsistent. Here we focus on assessing the support for its underlying assumptions. 3. First, the evolutionary-rates hypothesis assumes that high energy levels promote mutation. There is certainly evidence that high levels of ultraviolet radiation increase mutation rates. High temperatures may also reduce generation times and elevate metabolic rates, which may promote mutation. On balance, data support a link between rates of metabolism and mutation, but a link between the latter and generation time is more equivocal and is particularly unlikely in plants. 4. Second, the evolutionary-rates hypothesis assumes that mutation rates limit speciation rates. This may be true if all else was equal, but correlations between mutation and speciation are probably very noisy as many other factors may influence rates both of sympatric and allopatric speciation, including the occurrence of physical isolation barriers, the magnitude of selection and population size. 5. Third, the evolutionary-rates hypothesis assumes that there is a strong correlation between current and historical energy levels. Factors such as tectonic drift may weaken such relationships, but are likely to have had negligible effects over the time period during which the majority of extant species evolved. 6. Fourth, the evolutionary-rates hypothesis assumes that changes in species ranges following speciation do not sufficiently weaken the correlation between the rate of speciation in an area and species richness. The ranges of many species appear to alter dramatically following speciation, and this may markedly reduce the strength of the relationship, but to what extent is unclear. 7. In sum, the degree to which the evolutionary-rates hypothesis can explain spatial variation in species richness remains surprisingly uncertain. We suggest directions for further research. © 2005 British Ecological Society.
Abstract.
Bonn A, Gaston KJ (2005). Capturing biodiversity: Selecting priority areas for conservation using different criteria.
Biodiversity and Conservation,
14(5), 1083-1100.
Abstract:
Capturing biodiversity: Selecting priority areas for conservation using different criteria
International treaties call for the protection of biodiversity in all its manifestations, including ecosystem and species diversities. The selection of most priority area networks focuses, however, primarily on species richness and occurrence. The effectiveness of this approach in capturing higher order manifestations of biodiversity, that is ecosystem and environmental diversity patterns, remains poorly understood. Using a case study of birds and environmental data from South Africa and Lesotho, we test how complementary networks that maximise species diversity perform with regard to their representation of ecosystem and environmental diversity, and vice versa. We compare these results to the performance of the existing reserve network. We conclude that focusing on any single biodiversity component alone is insufficient to protect other components. We offer explanations for this in terms of the autocorrelation of species diversity in environmental space. © Springer 2005.
Abstract.
Cassey P, Blackburn TM, Duncan RP, Gaston KJ (2005). Causes of exotic bird establishment across oceanic islands.
Proceedings of the Royal Society B: Biological Sciences,
272(1576), 2059-2063.
Abstract:
Causes of exotic bird establishment across oceanic islands
The probability that exotic species will successfully establish viable populations varies between regions, for reasons that are currently unknown. Here, we use data for exotic bird introductions to 41 oceanic islands and archipelagos around the globe to test five hypotheses for this variation: the effects of introduction effort, competition, predation, human disturbance and habitat diversity (island biogeography). Our analyses demonstrate the primary importance of introduction effort for avian establishment success across regions, in concordance with previous analyses within regions. However, they also reveal a strong negative interaction across regions between establishment success and predation; exotic birds are more likely to fail on islands with species-rich mammalian predator assemblages. © 2005 the Royal Society.
Abstract.
Cerdeira JO, Gaston KJ, Pinto LS (2005). Connectivity in priority area selection for conservation.
Environmental Modeling and Assessment,
10(3), 183-192.
Abstract:
Connectivity in priority area selection for conservation
The spatial relations of sites within networks of priority areas for conservation is critical to the long-term maintenance of key genetic, population and ecosystem processes. However, these relations have received relatively little attention in the development of mathematical methods for objectively identifying such networks. Here we present a novel heuristic for incorporating connectivity explicitly as part of the model constraints, provide an integer linear programming formulation for the same problem, describe an integer cutting procedure which defines a sequence of non-decreasing lower bounds on the optimal solution and report the results of some computational experiments using these algorithms. © Springer 2005.
Abstract.
Stuart SN, Archibald GW, Ball J, Berry RJ, Emmerich SD, Evans DM, Flenley JR, Gaston KJ, Given DR, Gosler AG, et al (2005). Conservation theology for conservation biologists - a reply to David Orr. Conservation Biology, 19(6), 1689-1692.
Parr CL, Sinclair BJ, Andersen AN, Gaston KJ, Chown SL (2005). Constraint and competition in assemblages: a cross-continental and modeling approach for ants.
American Naturalist,
165(4), 481-494.
Abstract:
Constraint and competition in assemblages: a cross-continental and modeling approach for ants
The mechanisms leading to structure in local assemblages are controversial. On the one hand, assemblage structure is thought to be the outcome of local interactions determined by the properties of species and their responses to the local environment. Alternatively, this structure has been shown to be an emergent property of assemblages of identical individuals or of random sampling of a regional assemblage. In ants at baits, a combination of environmental stress and interspecific competition is widely held to lead to a unimodal relationship between the abundance of dominant ants and species richness. It is thought that in comparatively adverse environments, both abundance and richness are low. As habitats become more favorable, abundance increases until the abundance of dominant ants is so high that they exclude those that are subordinate and so depress richness. Here we demonstrate empirically that this relationship is remarkably similar across three continents. Using a null model approach, we then show that the ascending part of the relationship is largely constrained to take this form not simply as a consequence of stress but also as a result of the shape of abundance frequency distributions. While the form of the species-abundance frequency distribution can also produce the descending part of the relationship, interspecific competition might lead to it too. Scatter about the relationship, which is generally not discussed in the literature, may well be a consequence of resource availability and environmental patchiness. Our results draw attention to the significance of regional processes in structuring ant assemblages. © 2005 by the University of Chicago.
Abstract.
Evans KL, Greenwood JJD, Gaston KJ (2005). Dissecting the species-energy relationship.
Proc Biol Sci,
272(1577), 2155-2163.
Abstract:
Dissecting the species-energy relationship.
Environmental energy availability can explain much of the spatial variation in species richness. Such species-energy relationships encompass a diverse range of forms, and there is intense debate concerning which of these predominate, and the factors promoting this diversity. Despite this there has been relatively little investigation of whether the form, and relative strength, of species-energy relationships varies with (i) the currency of energy availability that is used, and (ii) the ecological characteristics of the constituent species. Such investigations can, however, shed light on the causal mechanisms underlying species-energy relationships. We illustrate this using the British breeding avifauna. The strength of the species-energy relationship is dependent on the energy metric used, with species richness being more closely correlated with temperature than the Normalized Difference Vegetation Index, which is a strong correlate of net primary productivity. We find little evidence, however, for the thermoregulatory load hypothesis that high temperatures enable individuals to invest in growth and reproduction, rather than thermoregulation, increasing population sizes that buffer species from extinction. High levels of productive energy may also elevate population size, which is related to extinction risk by a negative decelerating function. Therefore, the rarest species should exhibit the strongest species-energy relationship. We find evidence to the contrary, together with little support for suggestions that high-energy availability elevates species richness by increasing the numbers of specialists or predators.
Abstract.
Author URL.
Evans KL, Warren PH, Gaston KJ (2005). Does energy availability influence classical patterns of spatial variation in exotic species richness?.
Global Ecology and Biogeography,
14(1), 57-65.
Abstract:
Does energy availability influence classical patterns of spatial variation in exotic species richness?
At macroecological scales, exotic species richness is frequently positively correlated with human population density. Such patterns are typically thought to arise because high human densities are associated with increased introduction effort and/or habitat modification and disturbance. Exotic and native species richness are also frequently positively correlated, although the causal mechanisms remain unclear. Energy availability frequently explains much of the variation in species richness and we test whether such species-energy relationships may influence the relationships of exotic species richness with human population density and native species richness. Location: Great Britain. Methods: We first investigate how spatial variation in the distributions of the 10 exotic bird species is related to energy availability. We then model exotic species richness using native avian species richness, human population density and energy availability as predictors. Species richness is modelled using two sets of models: one assumes independent errors and the other takes spatial correlation into account. Results: the probability of each exotic species occurring, in a 10-km quadrat, increases with energy availability. Exotic species richness is positively correlated with energy availability, human population density and native species richness in univariate tests. When taking energy availability into account, exotic species richness is negligibly influenced by human population density, but remains positively associated with native species richness. Main conclusions: We provide one of the few demonstrations that energy availability exerts a strong positive influence on exotic species richness. Within our data, the positive relationship between exotic species richness and human population density probably arises because both variables increase with energy availability, and may be independent of the influence of human density on the probability of establishment. Positive correlations between exotic and native species richness remain when controlling for the influence of energy on species richness. The relevance of such a finding to the debate on the relationship between diversity and invasibility is discussed. © 2005 Blackwell Publishing Ltd.
Abstract.
Webb TJ, Ian Woodward F, Hannah L, Gaston KJ (2005). Forest cover-rainfall relationships in a biodiversity hotspot: the Atlantic forest of Brazil.
Ecological Applications,
15(6), 1968-1983.
Abstract:
Forest cover-rainfall relationships in a biodiversity hotspot: the Atlantic forest of Brazil
It is now generally accepted that the relationship between vegetation and climate is dynamic: vegetation is influenced by climate, but feedbacks between terrestrial ecosystems and the atmosphere mean that vegetation also affects climate. From this it follows that land-use changes may have climatic consequences. Specifically, it is widely believed that forest clearance may inhibit rainfall. Although models often support this view, this is not universally the case, and empirical evidence is scarce. We have compiled a database of forest cover and precipitation for the state of São Paulo, which lies within the diverse and highly endangered Atlantic forest region of Brazil. We do not find a strong relationship between forest cover and total rainfall, which appears to be influenced primarily by factors such as distance to the coast; but significant positive relationships between tree cover and the number of rain days consistently emerge. The degree of forest fragmentation seems to influence this relationship, with patchier forests associated with fewer rain days; and tree cover also predicts interannual variability in rainfall. The directionality of these relationships is inferred by considering only sites which are known to have been forested in the recent past. Given that across São Paulo state there is no overall trend for a reduction in rainfall over the study period (1962-1992), it would appear that important local-scale processes may be hidden by regional trends. We discuss these results with reference to conservation strategies in fragmented landscapes. For instance, the spatial scale over which tree cover-precipitation relationships occur appears to be somewhat larger than that over which studies of tropical forest fragmentation typically operate, but similar to the area of habitat deemed necessary to maintain viable populations of several Atlantic forest species. © 2005 by the Ecological Society of America.
Abstract.
Blackburn TM, Petchey OL, Cassey P, Gaston KJ (2005). Functional diversity of mammalian predators and extinction in island birds.
Ecology,
86(11), 2916-2923.
Abstract:
Functional diversity of mammalian predators and extinction in island birds
The probability of a bird species going extinct on oceanic islands in the period since European colonization is predicted by the number of introduced predatory mammal species, but the exact mechanism driving this relationship is unknown. One possibility is that larger exotic predator communities include a wider array of predator functional types. These predator communities may target native bird species with a wider range of behavioral or life history characteristics. We explored the hypothesis that the functional diversity of the exotic predators drives bird species extinctions. We also tested how different. combinations of functionally important traits of the predators explain variation in extinction probability. Our results suggest a unique impact of each introduced mammal species on native bird populations, as opposed to a situation where predators exhibit functional redundancy. Further, the impact of each additional predator may be facilitated by those already present, suggesting the possibility of "invasional meltdown.". © 2005 by the Ecological Society of America.
Abstract.
Orme CDL, Davies RG, Burgess M, Eigenbrod F, Pickup N, Olson VA, Webster AJ, Ding TS, Rasmussen PC, Ridgely RS, et al (2005). Global hotspots of species richness are not congruent with endemism or threat.
Nature,
436(7053), 1016-1019.
Abstract:
Global hotspots of species richness are not congruent with endemism or threat
Biodiversity hotspots have a prominent role in conservation biology, but it remains controversial to what extent different types of hotspot are congruent. Previous studies were unable to provide a general answer because they used a single biodiversity index, were geographically restricted, compared areas of unequal size or did not quantitatively compare hotspot types. Here we use a new global database on the breeding distribution of all known extant bird species to test for congruence across three types of hotspot. We demonstrate that hotspots of species richness, threat and endemism do not show the same geographical distribution. Only 2.5% of hotspot areas are common to all three aspects of diversity, with over 80% of hotspots being idiosyncratic. More generally, there is a surprisingly low overall congruence of biodiversity indices, with any one index explaining less than 24% of variation in the other indices. These results suggest that, even within a single taxonomic class, different mechanisms are responsible for the origin and maintenance of different aspects of diversity. Consequently, the different types of hotspots also vary greatly in their utility as conservation tools.
Abstract.
Webb TJ, Gaston KJ (2005). Heritability of geographic range sizes revisited: a reply to Hunt et al. American Naturalist, 166(1), 136-143.
Chown SL, Hull B, Gaston KJ (2005). Human impacts, energy availability and invasion across Southern Ocean Islands.
Global Ecology and Biogeography,
14(6), 521-528.
Abstract:
Human impacts, energy availability and invasion across Southern Ocean Islands
Aim Ongoing biological invasions will enhance the impacts of humans on biodiversity. Nonetheless, the effects of exotic species on diversity are idiosyncratic. Increases in diversity might be a consequence of similar responses by species to available energy, or because of positive relationships between human density, energy and propagule pressure. Here we use data from the Southern Ocean island plants and insects to investigate these issues. Location the Southern Ocean Islands ranging from Tristan da Cunha to Heard Island and South Georgia. Methods Generalized linear models are used to explore the relationships between indigenous and exotic species richness for plants and insects on two different islands. Similar models are used to examine interactions between indigenous and exotic species richness, energy availability and propagule pressure at the regional scale. Results Positive relationships were found between indigenous and exotic species richness at local scales, although for plants, the relationship was partially triangular. Across the Southern Ocean Islands, there was strong positive covariation between indigenous and exotic plant species richness and insect species richness, even taking spatial autocorrelation into account. Both exotic and indigenous plant and insect species richness covaried with energy availability, as did human visitor frequency. When two islands with almost identical numbers of human visits were contrasted, it was clear that energy availability, or perhaps differences in climate-matching, were responsible for differences in the extent of invasion. Conclusion in plants and insects, there are positive relationships between indigenous and exotic diversity at local and regional scales across the Southern Ocean islands. These relationships are apparently a consequence of similar responses by both groups and by human occupants to available energy. When visitor frequency is held constant, energy availability is the major correlate of exotic species richness, though the exact mechanistic cause of this relationship requires clarification. © 2005 Blackwell Publishing Ltd.
Abstract.
Greve M, Gremmen NJM, Gaston KJ, Chown SL (2005). Nestedness of Southern Ocean island biotas: Ecological perspectives on a biogeographical conundrum.
Journal of Biogeography,
32(1), 155-168.
Abstract:
Nestedness of Southern Ocean island biotas: Ecological perspectives on a biogeographical conundrum
Aim: to use patterns of nestedness in the indigenous and non-indigenous biotas of the Southern Ocean islands to determine the influence of dispersal ability on biogeographical patterns, and the importance of accounting for variation in dispersal ability in their subsequent interpretation, especially in the context of the Insulantarctic and multi-regional hypotheses proposed to explain the biogeography of these islands. Location: Southern Ocean islands. Methods: Nestedness was determined using a new metric, d1 (a modification of discrepancy), for the indigenous and introduced seabirds, land birds, insects and vascular plants of 26 Southern Ocean islands. To assess the possible confounding effects of spatial autocorrelation on the results, islands were assigned to 11 major island groups and each group was treated as a single island in a following analysis. In addition, nestedness of the six Southern Ocean islands comprising the South Pacific Province (New Zealand islands) was analysed. All analyses were conducted for species and genera, for each of the taxa on its own, and for the complete data sets. Results: Statistically significant nestedness was found in all of the taxa examined, with nestedness declining in the order seabirds > land birds > vascular plants > insects for the indigenous species. Vagility had a marked influence on nestedness and the biogeographical patterns shown by the indigenous species. This influence was borne out by additional analyses of marine taxa and small-sized terrestrial species, both of which were more nested than the most nested group examined here, the seabirds. Assemblages of non-indigenous species also showed nestedness, and nestedness was generally more pronounced than in the indigenous species. Surprisingly, vagility had a significant effect on nestedness in these assemblages too. Main conclusions: Nestedness analyses provide a quantitative means of comparing biogeographical patterns for groups differing in vagility. These comparisons revealed that vagility has a considerable influence on biogeographical patterns and should be taken into account in analyses. Here, investigations of more vagile taxa support hypotheses for a single origin of the Southern Ocean island biota (the Insulantarctica scenario), whilst those of less mobile taxa support the more commonly held, multi-regional hypothesis. All biogeographical analyses across the Southern Ocean (and elsewhere) will be influenced by the effects of dispersal ability, with composite analyses dominated by sedentary groups likely to favour multi-regional scenarios, and those dominated by mobile groups favouring single origins. Mechanisms underlying nestedness in the region range from nested physiological tolerances in more mobile groups to colonization ability and patterns of speciation in less vagile taxa. Considerable nestedness in the non-indigenous assemblages is largely a consequence of the fact that many of these species are European weedy species.
Abstract.
Gaston KJ, Chown SL (2005). Neutrality and the niche. Functional Ecology, 19(1), 1-6.
Evans KL, Gaston KJ (2005). People, energy and avian species richness.
Global Ecology and Biogeography,
14(2), 187-196.
Abstract:
People, energy and avian species richness
Aim to investigate the inter-relationships between energy availability, species richness and human population density, particularly whether human population density influences the manner in which species richness responds to energy availability. Location British 10-km grid cells. Methods Using regressions, we inves tigate how human population density varies with energy availability and the nature of relationships between the numbers of species, classified by abundance and threat categories, and human population density. We then assess whether the relationships between these species richness measures and energy availability are altered when accounting for human population density. We conduct analyses using both independent error models and ones that control for spatial autocorrelation. Results Human population density was strongly and positively correlated with energy availability. Total species richness, and that of unthreatened, threatened, common and moderately common species, increases in a positive decelerating manner with human density. When human population density was taken into account, these species groups exhibited similar species-energy relationships, but the slopes of these relationships were significantly reduced in independent error models and, in the case of total richness, in spatial models. Main conclusions Positive correlations between human density and species richness probably arise as both increase with energy availability. Our data are compatible with the suggestion that high human population densities reduce the rate at which species richness increases with energy availability, but additional research is required before causality can be confirmed. © 2005 Blackwell Publishing Ltd.
Abstract.
Pérez-Arteaga A, Jackson SF, Carrera E, Gaston KJ (2005). Priority sites for wildfowl conservation in Mexico.
Animal Conservation,
8(1), 41-50.
Abstract:
Priority sites for wildfowl conservation in Mexico
A set of priority sites for wildfowl conservation in Mexico was determined using contemporary count data (1991-2000) from the U.S. Fish & Wildlife Service mid-winter surveys. We used a complementarity approach implemented through linear integer programming that addresses particular conservation concerns for every species included in the analysis and large fluctuations in numbers through time. A set of 31 priority sites was identified, which held more than 69% of the mid-winter count total in Mexico during all surveyed years. Six sites were in the northern highlands, 12 in the central highlands, six on the Gulf of Mexico coast and seven on the upper Pacific coast. Twenty-two sites from the priority set have previously been identified as qualifying for designation as wetlands of international importance under the Ramsar Convention and 20 sites are classified as Important Areas for Bird Conservation in Mexico. The information presented here provides an accountable, spatially-explicit, numerical basis for ongoing conservation planning efforts in Mexico, which can be used to improve existing wildfowl conservation networks in the country and can also be useful for conservation planning exercises elsewhere. © 2005 the Zoological Society of London.
Abstract.
Evans KL, Greenwood JJD, Gaston KJ (2005). Relative contribution of abundant and rare species to species-energy relationships.
Biol Lett,
1(1), 87-90.
Abstract:
Relative contribution of abundant and rare species to species-energy relationships.
A major goal of ecology is to understand spatial variation in species richness. The latter is markedly influenced by energy availability and appears to be influenced more by common species than rare ones; species-energy relationships should thus be stronger for common species. Species-energy relationships may arise because high-energy areas support more individuals, and these larger populations may buffer species from extinction. As extinction risk is a negative decelerating function of population size, this more-individuals hypothesis (MIH) predicts that rare species should respond more strongly to energy. We investigate these opposing predictions using British breeding bird data and find that, contrary to the MIH, common species contribute more to species-energy relationships than rare ones.
Abstract.
Author URL.
Pautasso M, Gaston KJ (2005). Resources and global avian assemblage structure in forests.
Ecology Letters,
8(3), 282-289.
Abstract:
Resources and global avian assemblage structure in forests
Explaining spatial variation in a number of bird species, particularly from temperate to tropical regions, has been a longstanding challenge. We test at a global scale whether species-rich forest assemblages are associated with division of a larger resource pool, a finer division of that pool, or some combination of the two. Species richness increases with increasing assemblage abundance, biomass and energy use. As assemblage abundance, biomass and energy use increase with increasing energy availability, and as per species numbers of individuals, biomass and energy use do not decrease with increasing energy availability, we provide direct evidence that the avian species-energy relationship in forests is associated foremost with an increase in the size of the resource pool and not with a finer level of its subdivision. ©2005 Blackwell Publishing Ltd/CNRS.
Abstract.
Blackburn TM, Cassey P, Duncan RP, Evans KL, Gaston KJ (2005). Response to comment on "Avian extinction and mammalian introductions on oceanic islands".
SCIENCE,
307(5714), 1412-1412.
Author URL.
Evans KL, Warren PH, Gaston KJ (2005). Species-energy relationships at the macroecological scale: a review of the mechanisms.
Biol Rev Camb Philos Soc,
80(1), 1-25.
Abstract:
Species-energy relationships at the macroecological scale: a review of the mechanisms.
Correlations between the amount of energy received by an assemblage and the number of species that it contains are very general, and at the macro-scale such species-energy relationships typically follow a monotonically increasing curve. Whilst the ecological literature contains frequent reports of such relationships, debate on their causal mechanisms is limited and typically focuses on the role of energy availability in controlling the number of individuals in an assemblage. Assemblages from high-energy areas may contain more individuals enabling species to maintain larger, more viable populations, whose lower extinction risk elevates species richness. Other mechanisms have, however, also been suggested. Here we identify and clarify nine principal mechanisms that may generate positive species-energy relationships at the macro-scale. We critically assess their assumptions and applicability over a range of spatial scales, derive predictions for each and assess the evidence that supports or refutes them. Our synthesis demonstrates that all mechanisms share at least one of their predictions with an alternative mechanism. Some previous studies of species-energy relationships appear not to have recognised the extent of shared predictions, and this may detract from their contribution to the debate on causal mechanisms. The combination of predictions and assumptions made by each mechanism is, however, unique, suggesting that, in principle, conclusive tests are possible. Sufficient testing of all mechanisms has yet to be conducted, and no single mechanism currently has unequivocal support. Each may contribute to species-energy relationships in some circumstances, but some mechanisms are unlikely to act simultaneously. Moreover, a limited number appear particularly likely to contribute frequently to species-energy relationships at the macro-scale. The increased population size, niche position and diversification rate mechanisms are particularly noteworthy in this context.
Abstract.
Author URL.
He F, Gaston KJ, Connor EF, Srivastava DS (2005). The local-regional relationship: Immigration, extinction, and scale.
Ecology,
86(2), 360-365.
Abstract:
The local-regional relationship: Immigration, extinction, and scale
While local processes (e.g. competition, predation, and disturbance) presumably cause species exclusion and thus limit diversity in individual communities, regional processes (e.g. historical events, immigration, and speciation) are assumed to provide a source of species to colonize and thus enrich local communities. Ecologists have attempted to distinguish between these two sets of processes using graphical evidence for local assemblage saturation. However, such efforts have been controversial and are antithetical to the fact that local diversity bears an imprint of both. We examine the local-regional species richness relationship from the perspective of the theory of island biogeography and develop a model that can produce the full range of observed local-regional richness relationships from linear to curvilinear. Importantly, unlike previous models, we do not require species interactions to produce the curvilinear pattern. Curvilinear relationships arise if per-species stochastic extinction rates are substantially higher than colonization rates, while linear relationships result if colonization rates are higher than extinction rates. Because we also show that merely changing the sampling scale can make local-regional relationships appear either saturated or unsaturated, an inference of ecological processes, derived solely from local-regional relationships, is unwarranted. © 2005 by the Ecological Society of America.
Abstract.
Williamson M, Gaston KJ (2005). The lognormal distribution is not an appropriate null hypothesis for the species-abundance distribution.
Journal of Animal Ecology,
74(3), 409-422.
Abstract:
The lognormal distribution is not an appropriate null hypothesis for the species-abundance distribution
1. of the many models for species-abundance distributions (SADs), the lognormal has been the most popular and has been put forward as an appropriate null model for testing against theoretical SADs. In this paper we explore a number of reasons why the lognormal is not an appropriate null model, or indeed an appropriate model of any sort, for a SAD. 2. We use three empirical examples, based on published data sets, to illustrate features of SADs in general and of the lognormal in particular: the abundance of British breeding birds, the number of trees > 1 cm diameter at breast height (d.b.h.) on a 50 ha Panamanian plot, and the abundance of certain butterflies trapped at Jatun Sacha, Ecuador. The first two are complete enumerations and show left skew under logarithmic transformation, the third is an incomplete enumeration and shows right skew. 3. Fitting SADs by χ2 test is less efficient and less informative than fitting probability plots. The left skewness of complete enumerations seems to arise from a lack of extremely abundant species rather than from a surplus of rare ones. One consequence is that the logit-normal, which stretches the right-hand end of the distribution, consistently gives a slightly better fit. 4. The central limit theorem predicts lognormality of abundances within species but not between them, and so is not a basis for the lognormal SAD. Niche breakage and population dynamical models can predict a lognormal SAD but equally can predict many other SADs. 5. The lognormal sits uncomfortably between distributions with infinite variance and the log-binomial. The latter removes the absurdity of the invisible highly abundant half of the individuals abundance curve predicted by the lognormal SAD. The veil line is a misunderstanding of the sampling properties of the SAD and fitting the Poisson lognormal is not satisfactory. A satisfactory SAD should have a thinner right-hand tail than the lognormal, as is observed empirically. 6. The SAD for logarithmic abundance cannot be Gaussian. © 2005 British Ecological Society.
Abstract.
Zapata FA, Gaston KJ, Chown SL (2005). The mid-domain effect revisited.
AMERICAN NATURALIST,
166(5), E144-E148.
Author URL.
Evans KL, Greenwood JJD, Gaston KJ (2005). The roles of extinction and colonization in generating species-energy relationships.
Journal of Animal Ecology,
74(3), 498-507.
Abstract:
The roles of extinction and colonization in generating species-energy relationships
1. Positive correlations between energy and species richness are frequently observed, but the causal mechanisms of such species-energy relationships have rarely been identified conclusively. 2. The more individuals hypothesis (MIH) describes one possible cause of positive species-energy relationships. It suggests that greater resource availability in high-energy areas increases population sizes, reducing local extinction rates and promoting species richness. It predicts that extinction rates will be lower in high-energy areas and that, because a given change in population size has a greater influence on extinction risk when initial populations are small, such relationships will be more pronounced in numerically rare species than more abundant ones. 3. Colonization rates may also influence local species richness, and they may respond positively to the greater resource abundance in high-energy areas. 4. We provide the first empirical test of relationships between extinction/ colonization rates and energy availability and of the influence of population size on these relationships. We use data on the changing distributions of British birds, in which positive species-energy relationships have previously been documented. 5. We find that extinction rates are lower in high-energy areas, but that such patterns are stronger in more abundant species. Spatial variation in colonization rates is influenced less markedly by energy availability, but such patterns are also more marked in numerically abundant species. While these results provide little overall support for the MIH, nor some of its alternatives, they add to increasing evidence that common species drive much of the spatial variation in species richness. © 2005 British Ecological Society.
Abstract.
Storch D, Evans KL, Gaston KJ (2005). The species-area-energy relationship.
Ecol Lett,
8(5), 487-492.
Abstract:
The species-area-energy relationship.
Area and available energy are major determinants of species richness. Although scale dependency of the relationship between energy availability and species richness (the species-energy relationship) has been documented, the exact relationship between the species-area and the species-energy relationship has not been studied explicitly. Here we show, using two extensive data sets on avian distributions in different biogeographic regions, that there is a negative interaction between energy availability and area in their effect on species richness. The slope of the species-area relationship is lower in areas with higher levels of available energy, and the slope of the species-energy relationship is lower for larger areas. This three-dimensional species-area-energy relationship can be understood in terms of probabilistic processes affecting the proportions of sites occupied by individual species. According to this theory, high environmental energy elevates species' occupancies, which depress the slope of the species-area curve.
Abstract.
Author URL.
Gaston KJ, Davies RG, Gascoigne CE, Williamson M (2005). The structure of global species-range size distributions: Raptors & owls.
Global Ecology and Biogeography,
14(1), 67-76.
Abstract:
The structure of global species-range size distributions: Raptors & owls
Aims to determine the shape of global species - range size distributions, the influence on these of island species, threatened species and patterns of latitudinal variation in range sizes, and the fit to logit-normal distributions. Location: Global. Methods: We takethe spatial distributions of the raptors and owls of the world as exemplar data sets, document the shapes of their species-range size distributions, the influence of particular groups of species and of latitudinal variation in range sizes on these shapes, and the fit of these distributions to a variety of models. Results: the global species- range size distributions of both raptors and owls are extremely right skewed on untransformed axes. They are not lognormally distributed, as has commonly been stated for species - range size distributions, nor logit-normally distributed as has been suggested might be the case. For raptors, departures from either a lognormal or a logit-normal are little mitigated by excluding groups of species that might be thought to distort the observed species - range size distribution, nor by the latitudinal gradient in geographical range size. For owls, the effects of excluding island and threatened species are more marked, with the fit of the species - range size distribution to a lognormal or a logit-normal becoming much closer. Conclusions: a simple general description of the shape of species - range size distributions remains elusive. This constitutes a significant constraint on the development of theory as to how they are determined. Whilst in principle the fit of any given mechanistic model can be tested against one or more empirical data sets, whatever their form, a simple general mathematical description of species - range size distributions would make the process of rapidly testing the appropriateness of mechanistic models more straightforward. © 2005 Blackwell Publishing Ltd.
Abstract.
Cannon AR, Chamberlain DE, Toms MP, Hatchwell BJ, Gaston KJ (2005). Trends in the use of private gardens by wild birds in Great Britain 1995-2002.
Journal of Applied Ecology,
42(4), 659-671.
Abstract:
Trends in the use of private gardens by wild birds in Great Britain 1995-2002
1. Wild birds are commonly observed in private residential gardens in Great Britain. However, little is known about how their use of this significant and increasingly important habitat is changing and how such changes relate to their population status. 2. Trends in the use of private residential gardens by wild birds in Great Britain were investigated using weekly bird records from 18 300 gardens over 8 years. 3. We showed that the use of this habitat is seasonal and cyclic, with the timing and regularity of its periodicity variable between species. 4. We evaluated the significance of the underlying trends in the cyclic reporting rates. Eighteen species showed clear trends, the three with the most negative year term parameter estimates being 'red-listed' as high conservation concern. 5. Examining correlations with national scale survey data suggested that garden reporting rates are related to general population trends in a number of species, including several of conservation importance. Other species exhibit important differences between national and garden trends. 6. Synthesis and applications. Our analysis demonstrates ecologically meaningful trends and provides novel insights into seasonal cycles of habitat exploitation, using relatively simple and cost-effectively collected data. This will lead to greater understanding of the relationships between gardens and general bird populations and of the times of year at which garden habitats are most important for birds. We have demonstrated the practicality and productivity of 'citizen science' in this context, and provided new information on the status of some birds of conservation concern. © 2005 British Ecological Society.
Abstract.
Storch D, Marquet PA, Gaston KJ (2005). Untangling an entangled bank. Science, 307(5710), 684-686.
Gaston KJ, Smith RM, Thompson K, Warren PH (2005). Urban domestic gardens (II): Experimental tests of methods for increasing biodiversity.
Biodiversity and Conservation,
14(2), 395-413.
Abstract:
Urban domestic gardens (II): Experimental tests of methods for increasing biodiversity
The extent and continued expansion of urbanisation has focused attention on the significance for native biodiversity of those green spaces remaining within such areas and the most appropriate methods of managing them. In the UK, a high proportion of urban space is comprised of the private or domestic gardens associated with residential dwellings, and many recommendations have been made for simple changes to improve their value for biodiversity ('wildlife gardening'). Here, we report the results of replicated experimental tests of five such common recommendations, involving the introduction to gardens of (i) artificial nest sites for solitary bees and wasps; (ii) artificial nest sites for bumblebees; (iii) small ponds; (iv) dead wood for fungi and other saproxylic organisms; and (v) patches of nettles Urtica dioica L. for butterfly larvae. The broad conclusion is that whilst some methods for increasing the biodiversity of garden environments may be very effective, others have a low probability of success on the timescales and spatial scales likely to be acceptable to many garden owners. If one of the functions of small scale biodiversity enhancement is to develop and encourage awareness of biodiversity and its conservation, then encouragement to conduct particular activities must be balanced with a realistic appraisal of their likely success. © Springer 2005.
Abstract.
Gaston KJ, Warren PH, Thompson K, Smith RM (2005). Urban domestic gardens (IV): the extent of the resource and its associated features.
Biodiversity and Conservation,
14(14), 3327-3349.
Abstract:
Urban domestic gardens (IV): the extent of the resource and its associated features
Domestic ('private') gardens constitute a substantial proportion of 'green space' in urban areas and hence are of potential significance for the maintenance of biodiversity in such areas. However, the size and nature of this resource and its associated features are poorly known. In this study, we provide the first detailed audit, using domestic gardens in the city of Sheffield as a model study system. Domestic gardens, the mean area of which was 151 m 2, cover approximately 33 km2 or 23% of the predominantly urban area of the city. The smaller gardens contribute disproportionately to this total because, although individually they add little, they are large in number. Conversely, the regions of the city with proportionately more garden area contribute most to the total garden area of the city, although such regions are limited in number. Based on the findings of a telephone based survey, 14.4% of dwellings with gardens were estimated to have ponds, 26% to have nest-boxes, 29% to have compost heaps, 48% to hold trees more than 3 m tall, and 14% of dwellings were estimated to be home to one or more cats. Whilst the absolute frequency of these features is low to moderate, by extrapolation they nonetheless yield estimates for domestic gardens in Sheffield of a total of 25,200 ponds, 45,500 nest boxes, 50,750 compost heaps, 360,000 trees, and a population of 52,000 domestic cats. These results are considered in the context of the role of gardens in urban areas as habitats for wildlife and the implications for housing policy. © Springer 2005.
Abstract.
Smith RM, Gaston KJ, Warren PH, Thompson K (2005). Urban domestic gardens (V): Relationships between landcover composition, housing and landscape.
Landscape Ecology,
20(2), 235-253.
Abstract:
Urban domestic gardens (V): Relationships between landcover composition, housing and landscape
The contribution to urban green space by private or domestic gardens in residential zones was investigated in the city of Sheffield, UK, as part of a wider study of the garden resource and its associated biodiversity. The attributes of 61 gardens, including patterns of landcover and vegetation cover, were explored in relation to housing characteristics and the nature of the surrounding landscape. The number of surrounding houses, and the areas of buildings and of roads were negatively correlated with garden area. The proportion of a housing parcel comprising garden increased with parcel size, although the proportion that was rear garden remained relatively constant. Garden size played an overwhelming role in determining garden composition: larger gardens supported more landcovers, contained greater extents of three-quarters of the recorded landcovers, and were more likely to contain trees taller than 2 m, vegetable patches, and composting sites. Unvegetated landcovers made greater proportional contributions as garden size declined. All categories of vegetation canopy increased with garden size, and large gardens supported disproportionately greater cover above 3 m. House age was a less significant factor determining garden landcover. Gardens of newer houses were more likely to occur towards the edge of the urban area, and older properties, that contained fewer hedges, possessed less canopy between 2-3 m. The extent and occurrence of different landcovers in gardens, and their consequences for wildlife, are considered for residential patches in urban areas. The implications for urban planners are discussed. © Springer 2005.
Abstract.
Thompson K, Colsell S, Carpenter J, Smith RM, Warren PH, Gaston KJ (2005). Urban domestic gardens (VII): a preliminary survey of soil seed banks.
Seed Science Research,
15(2), 133-141.
Abstract:
Urban domestic gardens (VII): a preliminary survey of soil seed banks
As part of a larger survey of biodiversity in private gardens in Sheffield, UK, we examined the composition and diversity of the soil seed banks in each of 56 gardens. Six soil cores from each garden revealed 2759 seedlings of 119 taxa, although the real species richness is likely to be much higher than this. By far the most abundant species were weedy natives, while the most common alien was Buddleja davidii. Seeds of perennial herbs were more abundant than hundreds of all other life forms combined. More frequent species were also more abundant, but the relationship was weak. Numbers of species in the seed bank and in the garden flora were positively but very weakly related. Seeds were quite evenly distributed between 0-5 cm and 5-10 cm soil layers, and most seeds were of species known to have persistent seed banks. Seeds of some species were largely confined to gardens in which the plant was growing, but others were not. © CAB International 2005.
Abstract.
Gaston KJ, O'Neill MA (2004). Automated species identification: why not?.
Philos Trans R Soc Lond B Biol Sci,
359(1444), 655-667.
Abstract:
Automated species identification: why not?
Where possible, automation has been a common response of humankind to many activities that have to be repeated numerous times. The routine identification of specimens of previously described species has many of the characteristics of other activities that have been automated, and poses a major constraint on studies in many areas of both pure and applied biology. In this paper, we consider some of the reasons why automated species identification has not become widely employed, and whether it is a realistic option, addressing the notions that it is too difficult, too threatening, too different or too costly. Although recognizing that there are some very real technical obstacles yet to be overcome, we argue that progress in the development of automated species identification is extremely encouraging that such an approach has the potential to make a valuable contribution to reducing the burden of routine identifications. Vision and enterprise are perhaps more limiting at present than practical constraints on what might possibly be achieved.
Abstract.
Author URL.
Blackburn TM, Cassey P, Duncan RP, Evans KL, Gaston KJ (2004). Avian extinction and mammalian introductions on oceanic islands.
Science,
305(5692), 1955-1958.
Abstract:
Avian extinction and mammalian introductions on oceanic islands
The arrival of humans on oceanic islands has precipitated a wave of extinctions among the islands' native birds. Nevertheless, the magnitude of this extinction event varies markedly between avifaunas. We show that the probability that a bird species has been extirpated from each of 220 oceanic islands is positively correlated with the number of exotic predatory mammal species established on those islands after European colonization and that the effect of these predators is greater on island endemic species. In contrast, the proportions of currently threatened species are independent of the numbers of exotic mammalian predator species, suggesting that the principal threat to island birds has changed through time as species susceptible to exotic predators have been driven extinct.
Abstract.
Gaston KJ, Evans KL (2004). Birds and people in Europe.
Proc Biol Sci,
271(1548), 1649-1655.
Abstract:
Birds and people in Europe.
At a regional scale, species richness and human population size are frequently positively correlated across space. Such patterns may arise because both species richness and human density increase with energy availability. If the species-energy relationship is generated through the 'more individuals' hypothesis, then the prediction is that areas with high human densities will also support greater numbers of individuals from other taxa. We use the unique data available for the breeding birds in Europe to test this prediction. Overall regional densities of bird species are higher in areas with more people; species of conservation concern exhibit the same pattern. Avian density also increases faster with human density than does avian biomass, indicating that areas with a higher human density have a higher proportion of small-bodied individuals. The analyses also underline the low numbers of breeding birds in Europe relative to humans, with a median of just three individual birds per person, and 4 g of bird for every kilogram of human.
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Author URL.
Van Rensburg BJ, Erasmus BFN, Van Jaarsveld AS, Gaston KJ, Chown SL (2004). Conservation during times of change: Correlations between birds, climate and people in South Africa.
South African Journal of Science,
100(5-6), 266-272.
Abstract:
Conservation during times of change: Correlations between birds, climate and people in South Africa
Few studies have investigated the ability of national conservation networks to adapt to changes in underlying environmental drivers (such as precipitation) and their consequences for factors such as human density and species richness patterns. In this article, the South African avifauna is used as the basis for such analysis to ascertain the likely extent of current, and future, anthropogenic impacts on priority conservation areas. We show that human population pressure is high in or around most of these priority areas and is likely to increase, given the magnitude of post-climate change estimated from predicted changes in precipitation and relationships between species richness, human densities, and rainfall. Although additional conservation areas, such as the Important Bird Area (IBA) network, are likely to introduce valuable flexibility to conservation management, only limited options are available for such expansions, and the conservation value of these areas is likely to be compromised by changing climate. Ultimately, a more integrated conservation approach is needed for effective conservation policies. Such an approach should confer adequate protection on current reserves and emphasize sustainable utilization of non-reserve areas.
Abstract.
Lennon JJ, Koleff P, Greenwood JJD, Gaston KJ (2004). Contribution of rarity and commonness to patterns of species richness.
Ecology Letters,
7(2), 81-87.
Abstract:
Contribution of rarity and commonness to patterns of species richness
There is little understanding in ecology as to how biodiversity patterns emerge from the distribution patterns of individual species. Here we consider the question of the contributions of rare (restricted range) and common (widespread) species to richness patterns. Considering a species richness pattern, is most of the spatial structure, in terms of where the peaks and troughs of diversity lie, caused by the common species or the rare species (or neither)? Using southern African and British bird richness patterns, we show here that commoner species are most responsible for richness patterns. While rare and common species show markedly different species richness patterns, most spatial patterning in richness is caused by relatively few, more common, species. The level of redundancy we found suggests that a broad understanding of what determines the majority of spatial variation in biodiversity may be had by considering only a minority of species.
Abstract.
Cowling J, Spicer JI, Gaston KJ, Weeks JM (2004). Current status of an amphipod invader, Arcitalitrus dorrieni (Hunt, 1925), in Britain. Journal of Natural History, 38(13), 1665-1675.
Rodrigues ASL, Andelman SJ, Bakan MI, Boitani L, Brooks TM, Cowling RM, Fishpool LDC, Da Fonseca GAB, Gaston KJ, Hoffmann M, et al (2004). Effectiveness of the global protected area network in representing species diversity.
Nature,
428(6983), 640-643.
Abstract:
Effectiveness of the global protected area network in representing species diversity
The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform-that is, 'one size fits all'-conservation targets.
Abstract.
Gaston KJ, Smith RM, Thompson K, Warren PH (2004). Gardens and wildlife - the BUGS project. British Wildlife, 16(1), 1-9.
Rodrigues ASL, Akçakaya HR, Andelman SJ, Bakarr MI, Boitani L, Brooks TM, Chanson JS, Fishpool LDC, Da Fonseca GAB, Gaston KJ, et al (2004). Global gap analysis: Priority regions for expanding the global protected-area network.
BioScience,
54(12), 1092-1100.
Abstract:
Global gap analysis: Priority regions for expanding the global protected-area network
Protected areas are the single most important conservation tool. The global protected-area network has grown substantially in recent decades, now occupying 11.5% of Earth's land surface, but such growth has not been strategically aimed at maximizing the coverage of global biodiversity. In a previous study, we demonstrated that the global network is far from complete, even for the representation of terrestrial vertebrate species. Here we present a first attempt to provide a global framework for the next step of strategically expanding the network to cover mammals, amphibians, freshwater turtles and tortoises, and globally threatened birds. We identify unprotected areas of the world that have remarkably high conservation value (irreplaceability) and are under serious threat. These areas concentrate overwhelmingly in tropical and subtropical moist forests, particularly on tropical mountains and islands. The expansion of the global protected-area network in these regions is urgently needed to prevent the loss of unique biodiversity.
Abstract.
Chown SL, Sinclair BJ, Leinaas HP, Gaston KJ (2004). Hemispheric asymmetries in biodiversity - a serious matter for ecology. PLoS Biology, 2(11).
Petchey OL, Hector A, Gaston KJ (2004). How do different measures of functional diversity perform?.
Ecology,
85(3), 847-857.
Abstract:
How do different measures of functional diversity perform?
Biodiversity can influence ecosystem functioning through changes in the amount of resource use complementary among species. Functional diversity is a measure of biodiversity that aims to quantify resource use complementarity and thereby explain and predict ecosystem functioning. The primary goal of this article is to compare the explanatory power of four measures of functional diversity: species richness, functional group richness, functional attribute diversity, and FD. The secondary goal is to showcase the novel methods required for calculating functional attribute diversity and FD. We find that species richness and functional group richness explain the least variation in aboveground biomass production within and across grassland biodiversity manipulations at six European locations; functional attribute diversity and FD explain greater variation. Reasons for differences in explanatory power are discussed, such as the relatively greater amount of information and fewer assumptions included in functional attribute diversity and FD. We explore the opportunities and limitations of the particular methods we used to calculate functional attribute diversity and FD. These mainly concern how best to select the information used to calculate them.
Abstract.
Blackburn TM, Gaston KJ (2004). Macroecology. Basic and Applied Ecology, 5(5), 385-387.
Gaston KJ (2004). Macroecology and people.
Basic and Applied Ecology,
5(4), 303-307.
Abstract:
Macroecology and people
A macroecological perspective has become recognised as an important component of ecological studies, serving particularly to crystallise the notion that processes operating at large spatial (geographic) and temporal scales often play important roles in shaping species assemblages and communities at more local scales. However, within the field, consideration has been surprisingly lacking of the influence of humans in shaping macroecological patterns, the determinants of those patterns, or their consequences for local assemblages and communities. Here I briefly review the reasons why this might be so, and the possible interactions between macroecology and people, and suggest some simple steps for exploring this issue. © 2004 Elsevier GmbH. All rights reserved.
Abstract.
Chown SL, Gaston KJ, Robinson D (2004). Macrophysiology: Large-scale patterns in physiological traits and their ecological implications. Functional Ecology, 18(2), 159-167.
Cowling JE, Weeks JA, Spicer JI, Gaston KJ (2004). Physiological tolerances of the euterrestrial amphipod Arcitalitrus dorrieni (Hunt) as a key to its geographical distribution? a test using mesocosms. Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology, 139(2), 251-259.
Vázquez LB, Gaston KJ (2004). Rarity, commonness, and patterns of species richness: the mammals of Mexico.
Global Ecology and Biogeography,
13(6), 535-542.
Abstract:
Rarity, commonness, and patterns of species richness: the mammals of Mexico
Aim to determine whether rare or common species contribute most to overall patterns of spatial variation in extant species richness. Location Mexico. Methods Using data on the distribution of mammal species across Mexico at a quarter degree resolution, we ranked species from the most widespread to the most restricted (common-to-rare) within the study area, and from the most restricted to the most widespread (rare-to-common), and generated a sequence of patterns of species richness for increasing numbers of species. At each stage along both series of richness patterns, we correlated the species richness pattern for the subassemblage with that of the full assemblage. This allows comparison of subassemblages of the n most common with the n most rare species, in terms of how well they match the full assemblage richness pattern. Further analyses examined the effects on these patterns of correlation of the amount of raw information contained in the distributions of given numbers of rare and common species. Results for the mammals of Mexico the more widely distributed species contribute disproportionately to patterns of species richness compared with more restricted species, particularly for non-volant species and endemic species. This is not simply a consequence of differences in the volumes of information contained in the distributions of rare and common species, with the disproportionate contribution of common species if anything being sharpened when these differences are taken into account. The pattern is most clearly demonstrated by endemic species, suggesting that the contribution of common species is clearest when the causes of rarity and commonness are limited to those genuinely resulting in narrow and widespread geographical ranges, respectively, rather than artificial (e.g. geopolitical) boundaries to the extents of study regions. Conclusions Perhaps surprisingly, an understanding of the determinants of overall patterns of species richness may gain most from consideration of why common species occur in some areas and are absent from others, rather than consideration of the distributions of rare species. © 2004 Blackwell Publishing Ltd.
Abstract.
Jackson SF, Kershaw M, Gaston KJ (2004). Size matters: the value of small populations for wintering waterbirds.
Animal Conservation,
7(3), 229-239.
Abstract:
Size matters: the value of small populations for wintering waterbirds
Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks. © 2004 the Zoological Society of London.
Abstract.
Van Rensburg BJ, Koleff P, Gaston KJ, Chown SL (2004). Spatial congruence of ecological transition at the regional scale in South Africa.
Journal of Biogeography,
31(5), 843-854.
Abstract:
Spatial congruence of ecological transition at the regional scale in South Africa
Aim: to determine whether patterns of avian species turnover reflect either biome or climate transitions at a regional scale, and whether anthropogenic landscape transformation affects those patterns. Location: South Africa and Lesotho. Methods: Biome and land transformation data were used to identify sets of transition areas, and avian species occurrence data were used to measure species turnover rates (β-diversity). Spatial congruence between areas of biome transition, areas of high vegetation heterogeneity, high climatic heterogeneity, and high β-diversity was assessed using random draw techniques. Spatial overlap in anthropogenically transformed areas, areas of high climatic heterogeneity and high β-diversity areas was also assessed. Results: Biome transition areas had greater vegetation heterogeneity, climatic heterogeneity, and β-diversity than expected by chance. For the land transformation transition areas, this was only true for land transformation heterogeneity values and for one of the β-diversity measures. Avian presence/ absence data clearly separated the biome types but not the land transformation types. Main conclusions: Biome edges have elevated climatic and vegetation heterogeneity. More importantly, elevated β-diversity in the avifauna is clearly reflected in the heterogeneous biome transition areas. Thus, there is spatial congruence in biome transition areas (identified on vegetation and climatic grounds) and avian turnover patterns. However, there is no congruence between avian turnover and land transformation transition areas. This suggests that biogeographical patterns can be recovered using modern data despite landscape transformation.
Abstract.
Bonn A, Storch D, Gaston KJ (2004). Structure of the species--energy relationship.
Proc Biol Sci,
271(1549), 1685-1691.
Abstract:
Structure of the species--energy relationship.
The relationship between energy availability and species richness (the species-energy relationship) is one of the best documented macroecological phenomena. However, the structure of species distribution along the gradient, the proximate driver of the relationship, is poorly known. Here, using data on the distribution of birds in southern Africa, for which species richness increases linearly with energy availability, we provide an explicit determination of this structure. We show that most species exhibit increasing occupancy towards more productive regions (occurring in more grid cells within a productivity class). However, average reporting rates per species within occupied grid cells, a correlate of local density, do not show a similar increase. The mean range of used energy levels and the mean geographical range size of species in southern Africa decreases along the energy gradient, as most species are present at high productivity levels but only some can extend their ranges towards lower levels. Species turnover among grid cells consequently decreases towards high energy levels. In summary, these patterns support the hypothesis that higher productivity leads to more species by increasing the probability of occurrence of resources that enable the persistence of viable populations, without necessarily affecting local population densities.
Abstract.
Author URL.
Jackson SF, Kershaw M, Gaston KJ (2004). The buffer effect and the selection of protected areas for waterbirds in Britain.
Biological Conservation,
120(1), 137-143.
Abstract:
The buffer effect and the selection of protected areas for waterbirds in Britain
The buffer effect predicts that where the reproductive success and survivorship of a species vary between potential habitats, sites will be sequentially filled according to a preference hierarchy. Once favoured sites reach saturation, numbers on the less-suitable/poorer quality sites will show a greater rate of increase compared with those on favoured sites. Supporting evidence for a buffer effect is readily available in the literature for many species, although this is generally restricted to small-scale analyses. In this paper we test for a buffer effect on a national scale for 19 species of waterbirds regularly wintering in the UK for which populations have increased nationally. The results provide little support for the effect, with only four species showing significant negative correlations. Nonetheless, a number of factors are likely to confound the occurrence/identification of a buffer effect for these species, including site area and data limitations. By contrast, for the majority of these 19 species, those sites where initial population totals are largest are also those with the fastest rates of population increase. Encouragingly, these sites are, therefore, more likely to be classified and managed as Special Protection Areas (SPAs) or Ramsar sites using the current numerical criteria for identifying such conservation areas. © 2004 Elsevier Ltd. All rights reserved.
Abstract.
Gaston KJ, Genney DR, Thurlow M, Hartley SE (2004). The geographical range structure of the holly leaf-miner. IV. Effects of variation in host-plant quality.
Journal of Animal Ecology,
73(5), 911-924.
Abstract:
The geographical range structure of the holly leaf-miner. IV. Effects of variation in host-plant quality
1. Spatial variation and covariation in host-plant quality, herbivore abundance and herbivore mortality were examined across the natural geographical range in Europe of holly Ilex aquifolium and the host-specific holly leaf-miner Phytomyza ilicis. 2. Although measures of host-plant quality showed substantial between-site variation, no simple spatial pattern in any of the measures (only phosphorus content and leaf mass showed correlations with latitude, longitude or altitude) was detected, and few correlations with tree or local site characteristics. 3. In contrast, measures of the abundance of the leaf-miner exhibited marked spatial patterns, resulting in a lack of simple covariance between leaf-miner abundance and host-plant quality. 4. Different apparent mortalities of the leaf-miner exhibited varied spatial patterns in their intensity, but no evidence of range-wide density dependence, again resulting in few patterns of covariance between intensity of mortality and measures of host-plant quality. 5. The population dynamics of the holly leaf-miner across its geographical range are complex. At any site, the mortality that a population experiences is the sum of largely independent yet spatially structured components, against a background of varying host-plant quality. Despite lacking any marked spatial structure, host-plant quality may have important local effects. These are difficult to detect regionally, and thus may principally contribute noise to regional patterns of levels of oviposition, abundance and mortality.
Abstract.
Holt AR, Warren PH, Gaston KJ (2004). The importance of habitat heterogeneity, biotic interactions and dispersal in abundance-occupancy relationships.
Journal of Animal Ecology,
73(5), 841-851.
Abstract:
The importance of habitat heterogeneity, biotic interactions and dispersal in abundance-occupancy relationships
1. In simple microcosm systems, the form of interspecific abundance-occupancy relationships has been found to be dependent on biotic interactions. However, in more complex systems such effects may be obscured by those of habitat heterogeneity. Here we test this proposal using laboratory microcosms of protists and bacteria. 2. The independent effects of species interactions and heterogeneity were tested by comparison of the abundance-occupancy relationship formed in multiple habitat patch systems containing all species together, with that relationship formed by combining data from equivalent systems containing each protist species alone and between homogeneous and heterogeneous environments. 3. There was more residual variation about positive interspecific abundance-occupancy relationships formed in heterogeneous environments in interacting and non-interacting communities as the majority of species were more restricted in the number of patches they could occupy compared to homogeneous landscapes. 4. Abundance-occupancy relationships in interacting communities were better defined than those in non-interacting communities. The inclusion of interspecific interactions caused a reduction in the abundance and occupancy of the majority of species and changed the position of species within the relationship. 5. Our results show that biotic interactions influence the abundance-occupancy relationships even with imposed environmental heterogeneity. However, in heterogeneous environments, for some species these processes occurred in fewer patches, causing increased residual variation about positive interspecific abundance-occupancy relationships compared to homogeneous environments.
Abstract.
Jackson SF, Kershaw M, Gaston KJ (2004). The performance of procedures for selecting conservation areas: Waterbirds in the UK.
Biological Conservation,
118(2), 261-270.
Abstract:
The performance of procedures for selecting conservation areas: Waterbirds in the UK
In recent years, much attention has been directed to the ways in which the most important areas for inclusion in reserve networks can be identified, and the most effective ways in which existing networks can be expanded. In contrast, rather little attention has been paid to the present and likely future performance of the approaches that have actually been employed. Using Wetland Bird Survey data, the effectiveness of the current Special Protection Area (SPA) network in the UK was assessed by comparing annual counts for 17 species of migratory waterbird on SPAs with the numbers supported by hypothetical site networks selected by five alternative site-selection methods. These analyses suggest that focusing on complementarity between component sites rather than applying criteria to each site individually improved the level of representation for each species, conserved a greater percentage of the national total across the 17 species and was robust over time. © 2003 Elsevier Ltd. All rights reserved.
Abstract.
Storch D, Gaston KJ (2004). Untangling ecological complexity on different scales of space and time.
Basic and Applied Ecology,
5(5), 389-400.
Abstract:
Untangling ecological complexity on different scales of space and time
Ecological systems are complex and essentially unpredictable, because of the multitude of interactions among their constituents. However, there are general statistical patterns emerging on particular spatial and temporal scales, which indicate the existence of some universal principles behind many ecological phenomena, and which can even be used for the prediction of phenomena occurring on finer scales of resolution. These generalities comprise regular frequency distributions of particular macroscopic variables within higher taxa (body size, abundance, range size), relationships between such variables, and general patterns in species richness. All the patterns are closely related to each other and although there are only a few major explanatory principles, there are plenty of alternative explanations. Reconciliation of different approaches cannot be obtained without careful formulation of testable hypotheses and rigorous quantitative empirical research. Two especially promising ways of untangling ecological complexity comprise: (1) analysis of invariances, i.e. universal quantitative relationships observed within many different systems, and (2) detailed analysis of the anatomy of macroecological phenomena, i.e. explorations of how emergent multispecies patterns are related to regular patterns concerning individual species. © 2004 Elsevier GmbH. All rights reserved.
Abstract.
Thompson K, Hodgson JG, Smith RM, Warren PH, Gaston KJ (2004). Urban domestic gardens (III): Composition and diversity of lawn floras.
Journal of Vegetation Science,
15(3), 373-378.
Abstract:
Urban domestic gardens (III): Composition and diversity of lawn floras
Question: How do lawn floras compare with those of semi-natural grasslands? Are the compositions of lawn floras determined by local, within-garden factors (e.g. lawn management and size) or by regional factors (e.g. climate and location)? Are lawn floras nested (like semi-natural grasslands) or not (like cultivated parts of gardens)? Are there gradients of species composition within lawns? Location: Sheffield, UK. Methods: We examined the composition of the floras of entire lawns and of two 1-m2 lawn quadrats in 52 gardens. Results: a total of 159 species of vascular plants was recorded, 60 of them only once. Most lawn species were forbs, but most lawn cover consisted of grasses. Lawn species were predominantly natives. Bigger lawns had more species, but richness was not closely linked to other environmental or management variables. Composition of lawn floras varied with altitude, with woodland and wetland plants more common in the higher west of the city, and weeds of waste ground in the east. The species-area curve derived from 1-m2 lawn quadrats was very similar to that of semi-natural grasslands. Lawn quadrats were significantly nested, with rarer species mostly confined to more species-rich quadrats. Trampling-tolerant Poa annua was more abundant in the part of the lawn nearer the house. Conclusions: in most respects, lawns behaved much more like semi-natural grasslands than like cultivated flower beds and borders. Species composition of lawns is strongly influenced by local climate. Most lawns show an internal gradient of composition, linked to a gradient of intensity of use.
Abstract.
Pérez-Arteaga A, Gaston KJ (2004). Wildfowl population trends in Mexico, 1961-2000: a basis for conservation planning.
Biological Conservation,
115(3), 343-355.
Abstract:
Wildfowl population trends in Mexico, 1961-2000: a basis for conservation planning
We analysed population trends of 24 wildfowl species in Mexico. Wildfowl numbers peaked during the early 1980s; lowest counts were recorded in 1997. Total wildfowl numbers (all species combined) and duck numbers (duck species combined) showed significant short-term (1981-2000) declines, while geese (goose species combined) showed a significant long-term (1961-2000) increase. Six wildfowl species suffered significant long-term declines, while four showed increases. During 1981-2000, 11 species declined, but none had significant increases. Redhead (Aythya americana), Mexican duck (Anas diazi), northern pintail (A. acuta) and black brant (Branta bernicla nigricans) should be given high conservation priority because of the high proportions of their North American populations in Mexico. Declining numbers of the later two species should trigger further investigation into the possibility of assigning them legal protection status. Other species with apparent declines in numbers should also be more closely monitored. For setting hunting limits in the country, the population status of each species should be accounted for, as well as the condition of breeding populations the previous spring. Other species with poor data or combined counts should be targeted for basic population studies. We suggest that the mid-winter counts be expanded to cover non-surveyed areas and conducted every year to more precisely detect wildfowl population change. Integrated to a site-selection analysis, the information presented here can provide the basis for a wildfowl conservation strategy in Mexico. © 2003 Elsevier Ltd. All rights reserved.
Abstract.
Jones AG, Chown SL, Ryan PG, Gremmen NJM, Gaston KJ (2003). A review of conservation threats on Gough Island: a case study for terrestrial conservation in the Southern Oceans.
Biological Conservation,
113(1), 75-87.
Abstract:
A review of conservation threats on Gough Island: a case study for terrestrial conservation in the Southern Oceans
Gough Island is a remote Southern Ocean Island that, despite having no permanent human population, is under substantial conservation threat as a result of human activity. A considerable proportion of the flora and fauna has been accidentally introduced, and new data are presented showing that ca. 70% of the free-living pterygote insect species are introductions. We describe how endangered seabirds that breed on the island may suffer from human fisheries activities and present new evidence showing that local temperatures have risen significantly since 1963, threatening to alter the architecture and composition of species communities. These observations are an indication that the terrestrial ecosystems of other remote islands in the Southern Oceans may be under greater conservation threat than previously thought. In light of the threats described, we discuss conservation management priorities for Gough Island. To facilitate conservation of the indigenous biota, and that of similar islands elsewhere, we suggest that a combination of proactive measures designed to maintain the integrity of island communities, and monitoring programs designed rapidly to identify new conservation threats, should be implemented conscientiously. © 2003 Elsevier Science Ltd. All rights reserved.
Abstract.
Koleff P, Lennon JJ, Gaston KJ (2003). Are there latitudinal gradients in species turnover?.
Global Ecology and Biogeography,
12(6), 483-498.
Abstract:
Are there latitudinal gradients in species turnover?
Aim. To examine the effect on the observed relationship between spatial turnover and latitude of both the measure of beta diversity used and the method of analysis. Location. The empirical analyses presented herein are for the New World. Methods. We take the spatial distributions of the owls of the New World as an exemplar data set to investigate the patterns of beta diversity across latitudes revealed by different analytical methods. To illustrate the strenghts and weaknesses of alternative measures of beta diversity and different analytical approaches, we also use a simple random distribution model, focusing in particular on the influence of richness gradients and landmass geometry. Results. Our simple spatial model of turnover demonstrates that different combinations of analytical approach and measure of beta diversity can give rise to strikingly different ralationships between turnover and latitude. The analyses of the bird data for the owls of the New World demonstrate that this observation extends to real data. Conclusions. For the particular assemblage considered, we present strong evidence that species richness declines at higher latitudes, and there is also some evidence that species turnover is greater nearer the equator, despite conceptual and practical difficulties involved in analysing spatial patterns of species turnover. We suggest some ways of overcoming these difficulties.
Abstract.
Gaston KJ, Blackburn TM (2003). Dispersal and the interspecific abundance-occupancy relationship in British birds.
Global Ecology and Biogeography,
12(5), 373-379.
Abstract:
Dispersal and the interspecific abundance-occupancy relationship in British birds
Aim to test the prediction that deviations of species from the positive interspecific relationship between abundance and occupancy (a measure of geographical range size) are related to differences in dispersal. Location Great Britain. Methods Quantitative data on the abundances, occupancy and dispersal distances of British birds are compared using phylogenetic comparative methods. Results Measures of natal and adult dispersal distance, and the intraspecific variance in these parameters, explain little variation in occupancy in addition to that accounted for by population size. Individual dispersal variables failed to explain significant variance when added individually to a model with population size as a predictor. Migrants and species using wet habitats tend to disperse further than residents and dry habitat species. Analysing these four groups separately revealed effects of dispersal only on the occupancy attained by dry habitat species. Conclusions the only consistent predictor of occupancy in these analyses was population size.
Abstract.
Storch D, Konvicka M, Benes J, Martinková J, Gaston KJ (2003). Distribution patterns in butterflies and birds of the Czech Republic: Separating effects of habitat and geographical position.
Journal of Biogeography,
30(8), 1195-1205.
Abstract:
Distribution patterns in butterflies and birds of the Czech Republic: Separating effects of habitat and geographical position
Aim: to evaluate the relative role of environmental factors and geographical position (latitude and longitude) in determining species distribution and composition of local assemblages of butterflies and birds. Location: Czech Republic, central Europe. Methods: Canonical correspondence analysis that ordinates species and samples (grid cells in distribution atlases) such that interspecific and intersample differences attributable to environmental factors are maximized. The technique allowed us to test the significance of individual factors, including the geographical ones, by controlling the other factors and accounting for spatial autocorrelation. Results: Altitude and climate (temperature and precipitation) accounted for most variance in the interspecific differences in distribution of both butterflies and birds. The distribution of birds was also strongly affected by the area of water bodies, and less strongly, but still significantly, by the area of meadows and mountain open habitats. Habitat types important for the differences in butterfly distribution were deciduous forests, meadows, swamps and mountain open habitats. Some less common habitat types were important only because of the presence of rare species. Latitude and longitude invariably accounted for a large proportion of total variance, and their effect was highly significant even after controlling for the effect of all other environmental factors. Main conclusions: Although environmental factors, especially those related to elevation and climate, represent the main determinants of species distribution and composition of local assemblages, the geographical position is very important on this scale of resolution. Understanding distribution patterns, thus, must include not only an understanding of species ecological requirements, but also an understanding of geographical context, which affects structure and dynamics of species' geographical ranges.
Abstract.
Gaston KJ (2003). Ecology - the how and why of biodiversity.
NATURE,
421(6926), 900-901.
Author URL.
Chown SL, Van Rensburg BJ, Gaston KJ, Rodrigues ASL, Van Jaarsveld AS (2003). Energy, species richness, and human population size: Conservation implications at a national scale.
Ecological Applications,
13(5), 1233-1241.
Abstract:
Energy, species richness, and human population size: Conservation implications at a national scale
The maintenance of biodiversity rests on understanding and resolving conflict between patterns of species occurrence and human activity. Recent debate has centered on the relationship between species richness and human population density. However, conclusions have been limited by the lack of investigations of these relationships for individual countries, at which level most practical conservation actions are determined, and for a spatial resolution at which practical conservation planning takes place. Here, we report the results of the first such analysis, for birds in South Africa. Species richness and human density are positively correlated, apparently because both respond positively to increasing levels of primary productivity. High species richness is maintained by currently designated reserves, but the areas surrounding these have higher human population densities than expected by chance, placing the reserves under increasing external pressure. Not all species lie within protected areas, but the options are limited for building on the present network to generate a more comprehensive one, which protects all species and significantly reduces the conflict with human activities by designating new reserves in areas with lower human populations. Ultimately, the only solution to the conflict between biodiversity and people is likely to be individual-based regulation of human population size.
Abstract.
Cowling JE, Spicer JI, Weeks JM, Gaston KJ (2003). Environmental tolerances of an invasive terrestrial amphipod, Arcitalitrus dorrieni (Hunt) in Britain. Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology, 136(3), 735-747.
Storch D, Šizling AL, Gaston KJ (2003). Geometry of the species-area relationship in central European birds: Testing the mechanism.
Journal of Animal Ecology,
72(3), 509-519.
Abstract:
Geometry of the species-area relationship in central European birds: Testing the mechanism
1. The species-area relationship (SAR) is one of the major patterns in community ecology, but the mechanisms that contribute to its exact shape have remained obscure. In continuous mainland areas, the SAR has been attributed to sampling effects (large areas contain species that are too rare to be present in small areas), habitat heterogeneity (large areas contain more types of habitat allowing more species to coexist), and population and metapopulation processes causing spatial aggregation. We tested the contribution of these effects to SARs using data on breeding bird distributions in the Czech Republic, their total population sizes and spatial distributions of their preferred habitats. 2. The relationship between number of species and sampled area is more or less linear on a log-log scale within the Czech Republic, although it reveals saturation when the area is expanded to the whole of central Europe. 3. Neither sampling effect nor habitat heterogeneity alone explain the observed SAR shape: both models predict much higher species richness within any area and a SAR of much lower slope than observed. 4. A combined model based on random sampling constrained by the amount of suitable habitat within an area gives quite realistic predictions of species numbers within different sample areas. Nevertheless, the observed pattern reveals much higher variance of species richness amongst areas, species often being significantly more spatially aggregated than predicted by habitat distribution. 5. Moreover, the relationship between the amount of suitable habitat and the probability of quadrat occupancy is actually nonsignificant for about two-thirds of species, indicating that assumptions of the combined model are unrealistic. Therefore, the shape and slope of SARs are actually affected both by habitat heterogeneity that represents the major driver of distribution of some species, and by spatial aggregation that is not attributable to habitat heterogeneity in other species.
Abstract.
Balmford A, Gaston KJ, Blyth S, James A, Kapos V (2003). Global variation in terrestrial conservation costs, conservation benefits, and unmet conservation needs.
Proceedings of the National Academy of Sciences of the United States of America,
100(3), 1046-1050.
Abstract:
Global variation in terrestrial conservation costs, conservation benefits, and unmet conservation needs
Our ability to identify cost-efficient priorities for conserving biological diversity is limited by the scarcity of data on conservation costs, particularly at fine scales. Here we address this issue using data for 139 terrestrial programs worldwide. We find that the annual costs of effective field-based conservation vary enormously, across seven orders of magnitude, from $1,000,000 per km2. This variation can be closely predicted from positive associations between costs per unit area and an array of indices of local development. Corresponding measures of conservation benefit are limited but show opposing global trends, being higher in less developed parts of the world. The benefit-to-cost ratio of conservation is thus far greater in less developed regions, yet these are where the shortfall in current conservation spending is most marked. Substantially increased investment in tropical conservation is therefore urgently required if opportunities for cost-effective action are not to be missed.
Abstract.
Gaston KJ, Blackburn TM, Klein Goldewijk K (2003). Habitat conversion and global avian biodiversity loss.
Proc Biol Sci,
270(1521), 1293-1300.
Abstract:
Habitat conversion and global avian biodiversity loss.
The magnitude of the impacts of human activities on global biodiversity has been documented at several organizational levels. However, although there have been numerous studies of the effects of local-scale changes in land use (e.g. logging) on the abundance of groups of organisms, broader continental or global-scale analyses addressing the same basic issues remain largely wanting. None the less, changing patterns of land use, associated with the appropriation of increasing proportions of net primary productivity by the human population, seem likely not simply to have reduced the diversity of life, but also to have reduced the carrying capacity of the environment in terms of the numbers of other organisms that it can sustain. Here, we estimate the size of the existing global breeding bird population, and then make a first approximation as to how much this has been modified as a consequence of land-use changes wrought by human activities. Summing numbers across different land-use classes gives a best current estimate of a global population of less than 100 billion breeding bird individuals. Applying the same methodology to estimates of original land-use distributions suggests that conservatively this may represent a loss of between a fifth and a quarter of pre-agricultural bird numbers. This loss is shared across a range of temperate and tropical land-use types.
Abstract.
Author URL.
Holt AR, Gaston KJ (2003). Interspecific abundance-occupancy relationships of British mammals and birds: is it possible to explain the residual variation?.
Global Ecology and Biogeography,
12(1), 37-46.
Abstract:
Interspecific abundance-occupancy relationships of British mammals and birds: is it possible to explain the residual variation?
Aim. The majority of studies concerning positive interspecific abundance-occupancy relationships have used broad-scale and microcosm data to test the occurrence and correlates of the relationship to determine which of the proposed mechanisms give rise to it. It has been argued recently that studying the residual variation about abundance-occupancy relationships is a more logical analysis and may yield faster progress in identifying the relative roles of the mechanisms. However, to date this approach has been largely unsuccessful. Here we test if fundamental species traits such as the status (native and introduced), habitat and trophic group of mammal and bird species may explain any of the residual variation about their respective abundance-occupancy relationships. Location. The study used British mammal and bird species. Methods. We tested if species traits explained any of the variation about abundance-occupancy relationships using linear regression techniques both treating species as independent data points for analysis and controlling for phylogenetic association. Results. None of the species traits could explain any residual variation about the positive interspecific abundance-occupancy relationships of British mammals and birds. This applied both when treating species as independent data points and after controlling for phylogenetic association. Conclusion. Given the lack of explanatory power of the species traits here and in other studies using this approach it seems that the variation about positive interspecific abundance-occupancy relationships is not explicable in a simple fashion. Predicting the likely influence of traits that are independent of phylogeny is also problematic. Therefore, the general utility of this approach and its future role in understanding the mechanisms causing positive interspecific abundance-occupancy relationships is doubtful.
Abstract.
Jones AG, Chown SL, Gaston KJ (2003). Introduced house mice as a conservation concern on Gough Island.
Biodiversity and Conservation,
12(10), 2107-2119.
Abstract:
Introduced house mice as a conservation concern on Gough Island
House mice have previously been identified as a significant threat to both species and ecosystems on Southern Ocean islands. To date, these impacts have been quantified on several sub-Antarctic islands, but the role of house mice on more temperate islands is poorly known. On South Atlantic Gough Island, non-commensal house mice (Mus musculus L.) were probably introduced in the early 19th century and are now extremely abundant. To assess the likely impacts of mice on the fauna and flora at Gough Island we examined the diet of this population from September 1999 to July 2000 using conventional snap trapping techniques. The population has a single breeding season from September to March and mean body mass is notable in being amongst the largest reported for non-laboratory M. musculus. At low elevations (
Abstract.
Koleff P, Gaston KJ, Lennon JJ (2003). Measuring beta diversity for presence-absence data.
Journal of Animal Ecology,
72(3), 367-382.
Abstract:
Measuring beta diversity for presence-absence data
1. Little consensus has been reached as to general features of spatial variation in beta diversity, a fundamental component of species diversity. This could reflect a genuine lack of simple gradients in beta diversity, or a lack of agreement as to just what constitutes beta diversity. Unfortunately, a large number of approaches have been applied to the investigation of variation in beta diversity, which potentially makes comparisons of the findings difficult. 2. We review 24 measures of beta diversity for presence/absence data (the most frequent form of data to which such measures are applied) that have been employed in the literature, express many of them for the first time in common terms, and compare some of their basic properties. 3. Four groups of measures are distinguished, with a fundamental distinction arising between 'broad sense' measures incorporating differences in composition attributable to species richness gradients, and 'narrow sense' measures that focus on compositional differences independent of such gradients. On a number of occasions on which the former have been employed in the literature the latter may have been more appropriate, and there are many situations in which consideration of both kinds of measures would be valuable. 4. We particularly recommend (i) considering beta diversity measures in terms of matching/mismatching components (usually denoted a, b and c) and thereby identifying the contribution of different sources of variation in species composition, and (ii) the use of ternary plots to express the relationship between the values of these measures and of the components, and as a way of understanding patterns in beta diversity.
Abstract.
Zapata FA, Gaston KJ, Chown SL (2003). Mid-domain models of species richness gradients: Assumptions, methods and evidence.
Journal of Animal Ecology,
72(4), 677-690.
Abstract:
Mid-domain models of species richness gradients: Assumptions, methods and evidence
1. Patterns of species richness along latitudinal, elevational and depth gradients often exhibit a mid-gradient peak. Similar patterns with a mid-domain peak in richness are produced, as a result of geometric constraints on species distributions, by models that randomize species range size and placement over a bounded gradient. 2. Proponents of these so-called mid-domain models argue that they provide an appropriate null hypothesis for examining species richness patterns along spatial gradients. Furthermore, some claim that because these models seem to explain a large proportion of the large-scale spatial variation in richness, geometric constraints on species distribution are in fact the cause of these patterns. 3. A critical examination of model assumptions reveals that some are unrealistic, conceptually flawed or internally inconsistent. Additionally, tests of mid-domain models have suffered from methodological deficiencies derived from arbitrariness and circularity in the definition of domain boundaries, collapsing two-dimensional (2-D) patterns into a single dimension (1-D), and the use of interpolated ranges, all of which can bias test results in favour of the models. Tests have also been statistically naive by using fairly insensitive measures of deviation between observed and predicted patterns and ignoring the increased probability of Type I error that can result in analyses of spatially autocorrelated data. 4. In spite of this, a review of the empirical evidence indicates that most studies do not show a high degree of concordance between observed and predicted species richness patterns, particularly in 2-D. Additionally, spatial patterns of variation in range size and species turnover do not unequivocally support mid-domain models. Thus, the models do not adequately describe observed species richness gradients and thus fail to explain them. 5. Although mid-domain models have served a useful purpose in drawing attention to the need to clarify the null expectation in the study of species richness gradients, their use appears to be severely limited by difficulties associated with the treatment of ranges, boundary definitions and a lack of clarity regarding the extent to which the observed data should be used to generate the null patterns.
Abstract.
He F, Gaston KJ (2003). Occupancy, Spatial Variance, and the Abundance of Species. American Naturalist, 162(3), 366-375.
Webb TJ, Gaston KJ (2003). On the heritability of geographic range sizes.
Am Nat,
161(4), 553-566.
Abstract:
On the heritability of geographic range sizes.
Within taxonomic groups, most species are restricted in their geographic range sizes, with only a few being widespread. The possibility that species-level selection on range sizes contributes to the characteristic form of such species-range size distributions has previously been raised. This would require that closely related species have similar range sizes, an indication of "heritability" of range sizes at the species level. Support for this view came from a positive correlation between the range sizes of closely related pairs of fossil mollusc species. We extend this analysis by considering the relationship between the geographic range sizes of 103 pairs of contemporary avian sister species. Range sizes in these sister species show no evidence of being more similar to each other than expected by chance. A reassessment of the mollusc data also suggests that the high correlation was probably overestimated because of the skewed nature of range size data. The fact that sister species tend to have similar life histories and ecologies suggests that any relationship between range sizes and biology is likely to be complicated and will be influenced by historical factors, such as mode of speciation and postspeciation range size transformations.
Abstract.
Author URL.
Chown SL, Addo-Bediako A, Gaston KJ (2003). Physiological diversity: Listening to the large-scale signal. Functional Ecology, 17(4), 568-572.
Gaston KJ, Jones AG, Hänel C, Chown SL (2003). Rates of species introduction to a remote oceanic island.
Proc Biol Sci,
270(1519), 1091-1098.
Abstract:
Rates of species introduction to a remote oceanic island.
The introduction of species to areas beyond the limits of their natural distributions has a major homogenizing influence, making previously distinct biotas more similar. The scale of introductions has frequently been commented on, but their rate and spatial pervasiveness have been less well quantified. Here, we report the findings of a detailed study of pterygote insect introductions to Gough Island, one of the most remote and supposedly pristine temperate oceanic islands, and estimate the rate at which introduced species have successfully established. Out of 99 species recorded from Gough Island, 71 are established introductions, the highest proportion documented for any Southern Ocean island. Estimating a total of approximately 233 landings on Gough Island since first human landfall, this equates to one successful establishment for every three to four landings. Generalizations drawn from other areas suggest that this may be only one-tenth of the number of pterygote species that have arrived at the island, implying that most landings may lead to the arrival of at least one alien. These rates of introduction of new species are estimated to be two to three orders of magnitude greater than background levels for Gough Island, an increase comparable to that estimated for global species extinctions (many of which occur on islands) as a consequence of human activities.
Abstract.
Author URL.
Gaston KJ, Rodrigues ASL (2003). Reserve selection in regions with poor biological data.
Conservation Biology,
17(1), 188-195.
Abstract:
Reserve selection in regions with poor biological data
New approaches to the identification of priority areas for conservation are gaining popularity for their efficiency in maximizing species representation. However, their dependence on detailed distributional data severely hinders their application to regions where such information is limited, although these are commonly also the regions where conservation planning and action are most urgently required. We used exemplar data on the distribution of southern African birds to assess how sampling effort affects the performance of reserve networks selected by methods based on complementarity. We derived four scenarios of data availability from the initial data, resulting from different levels of sampling effort: abundance data, presence/absence data, low sampling effort, and absence of data. Reserve selection based on data obtained with low sampling effort can be highly effective in the representation of species, with a good relative performance also in terms of representation of species in peaks of abundance. This is because although the data on low sampling effort represent far fewer records than the original data, the records retained are biased toward the selection of peaks of abundance, even for the restricted-range species. Although the best results were naturally obtained from the most effort-intensive data set (with abundance data), these results suggest that methods based on complementarity are potentially valuable tools for reserve selection in regions for which biological data are poor.
Abstract.
Jones AJ, Chown SL, Webb TJ, Gaston KJ (2003). The free-living pterygote insects of gough island, south Atlantic Ocean.
Systematics and Biodiversity,
1(2), 213-273.
Abstract:
The free-living pterygote insects of gough island, south Atlantic Ocean
Gough Island, the furthest outlier of the Tristan da Cunha Island group, is a remote land mass in the South Atlantic Ocean. Pterygote insect species representing nine orders have been recorded on the island, the Psocoptera (booklice), Hemiptera (leafhoppers, aphids etc.), Thysanoptera (thrips), Coleoptera (beetles), Diptera (flies), Lepidoptera (moths), Hymenoptera (wasps etc.), and parasites of vertebrates in the Phthiraptera (lice) and Siphonaptera (fleas). Excluding parasites of vertebrates, 99 species have been recorded, 54 of which are recorded here for the first time. In total, 24 species occurring on Gough Island are thought to be endemic to the Tristan da Cunha Island group, four species are naturally occurring but found elsewhere, and 71 species are accidental introductions. The indigenous species have predominantly Neotropical associations, whilst the introduced ones are almost all globally widespread, the majority being of Holarctic origin. Approximately 28% of the introduced species are known to exhibit parthenogenesis compared with 7% of the indigenous species. In this paper we present keys and descriptions of all 99 species of pterygote insects, with notes on ecology, biology and conservation issues. © 2003 Taylor and Francis Group, LLC.
Abstract.
Klok CJ, Chown SL, Gaston KJ (2003). The geographical range structure of the Holly Leaf-miner. III. Cold hardiness physiology.
Functional Ecology,
17(6), 858-868.
Abstract:
The geographical range structure of the Holly Leaf-miner. III. Cold hardiness physiology
1. The thermal tolerances of a phytophagous insect, the Holly Leaf-miner Phytomyza ilicis Curtis, a specialist on holly Ilex aquifolium L. were investigated to determine whether these contribute to the high levels of miscellaneous larval mortalities that play an important role in determining the local abundances of this species across its geographical range. 2. Temperatures of crystallization, lower and upper lethal temperatures and rapid cold hardening experiments indicated that the Holly Leaf-miner has a pronounced cold hardiness, exceeding that of its host plant. Acute exposure to cold does not therefore contribute directly to miscellaneous mortalities and neither do summer temperatures exceed the upper lethal limits of the larvae. 3. Holly Leaf-miner densities are north-skewed; in the south densities gradually taper off and disappear well north of the distribution limits of the host plant. The parasitoid Chrysocharis gemma causes high larval mortalities in the centre of the distribution of the Holly Leaf-miner and is absent in the cold north, with the level of parasitism being positively correlated with miscellaneous mortalities. Only C. gemma adults overwinter and the attacks on Holly Leaf-miner, starting late winter, are likely opportunistic. This, and C. gemma's absence in the cold north, suggest significant cold susceptibility in C. gemma larvae. Thus, the greater proportion of miscellaneous larval mortalities of the Holly Leaf-miner are possibly the result of pre-premature deaths when C. gemma larvae are killed by cold snaps in late winter.
Abstract.
Brewer AM, Gaston KJ (2003). The geographical range structure of the holly leaf-miner. II. Demographic rates.
Journal of Animal Ecology,
72(1), 82-93.
Abstract:
The geographical range structure of the holly leaf-miner. II. Demographic rates
1. Few studies have sought to document the variation in demographic rates exhibited by local populations across the geographical range of a species. None the less, such information has the potential to yield insights into the factors that determine the internal abundance structure of ranges. 2. Major components of demographic rates are reported here for the holly leaf-miner Phytomyza ilicis Curtis across its natural geographical range in Europe, including areas at each of the extreme limits and at the core of its occurrence. 3. Correlograms reveal that a number of these components exhibit significant spatial structure across the geographical range and, in conjunction with interpolated maps, suggest that some of these patterns are, in terms of broad trends, reasonably simple. 4. Across the whole range, individual mortality components are largely independent of one another and of leaf-miner population densities, often exhibiting very different spatial patterns. Thus, P. ilicis populations experience markedly different mortality profiles across the range. 5. While some correlations between broad-scale environmental variation and the components of demographic rates were found, it was not possible to separate these effects from shared spatial structure. 6. In sum, the contribution of different components of demographic rates to local densities varies markedly across the geographical range of P. ilicis, and in isolation the pattern observed in any one locality provides limited information on what is occurring elsewhere, but these components none the less often exhibit systematic geographical patterns of variation.
Abstract.
Gaston KJ (2003). The how and why of biodiversity.
Nature,
421(6926), 900-901.
Abstract:
The how and why of biodiversity
A study of reef fish in the Indian and Pacific oceans reveals that the structures of local communities and their regional context are intricately entwined. New species spread far from an oceanic 'hotspot' of diversity.
Abstract.
Thompson K, Austin KC, Smith RM, Warren PH, Angold PG, Gaston KJ (2003). Urban domestic gardens (I): Putting small-scale plant diversity in context.
Journal of Vegetation Science,
14(1), 71-78.
Abstract:
Urban domestic gardens (I): Putting small-scale plant diversity in context
As part of a larger survey of biodiversity in gardens in Sheffield, UK, we examined the composition and diversity of the flora in two 1-m2 quadrats in each of 60 gardens, and compared this with floristic data from semi-natural habitats in central England and derelict urban land in Birmingham, UK. Garden quadrats contained more than twice as many taxa as those from any other habitat type. Ca. 33 % of garden plants were natives and 67 % aliens, mainly from Europe and Asia. A higher proportion of garden aliens originated from Asia and New Zealand than in the UK alien flora as a whole; 18 of the 20 most frequent plants in garden quadrats were natives, mostly common weeds. Garden quadrats showed no evidence of 'nestedness', i.e. a tendency for scarce species to be confined to the highest diversity quadrats. Conversely, species in all semi-natural and derelict land data sets were significantly nested. Compared to a range of semi-natural habitats, species richness of garden quadrats was intermediate, and strikingly similar to the richness of derelict land quadrats. Although species accumulation curves for all other habitats showed signs of saturation at 120 quadrats, gardens did not. Correlations between Sørensen similarity index and physical distance were insignificant for all habitat types, i.e. there was little evidence that physical distance played any part in structuring the composition of the quadrats in any of the data sets. However, garden quadrats were much less similar to each other than quadrats from semi-natural habitats or derelict land.
Abstract.
Williamson M, Gaston KJ, Lonsdale WM (2002). An asymptote is an asymptote and not found in species-area relationships. Journal of Biogeography, 29(12).
Jackson SF, Gaston KJ, Kershaw M (2002). Dealing with population fluctuations in waterbird conservation.
AVIAN LANDSCAPE ECOLOGY: PURE AND APPLIED ISSUES IN THE LARGE-SCALE ECOLOGY OF BIRDS, 242-250.
Author URL.
Petchey OL, Gaston KJ (2002). Extinction and the loss of functional diversity.
Proc Biol Sci,
269(1501), 1721-1727.
Abstract:
Extinction and the loss of functional diversity.
Although it is widely thought to influence ecosystem processes, there is little consensus on an appropriate measure of functional diversity. The two major perspectives, to date, are to assume that every species is functionally unique, or to assume that some species are functionally identical, such that functional groups exist. Using a continuous measure of functional diversity (FD) derived from the quantitative functional traits of species, we show that the loss of functional diversity from six natural assemblages was rapid compared with rates of loss from comparable simulated assemblages. Loss of FD occurred faster than loss of functional-group diversity in four of the six natural assemblages. Patterns of functional-group diversity loss depended on the number of functional groups and the number of species in an assemblage. Extinctions that occurred first for species with particular traits (e.g. low leaf nitrogen concentration, deep roots and large body size) caused greater loss of FD than expected by chance in four of the six natural assemblages. In two real assemblages, these trait-dependent extinctions had more severe effects on FD than our simulated worst-case extinction scenario. These data suggest that conserving a large proportion of the functional traits of species requires conserving a large proportion of all species.
Abstract.
Author URL.
Blackburn TM, Gaston KJ (2002). Extrinsic factors and the population sizes of threatened birds.
Ecology Letters,
5(4), 568-576.
Abstract:
Extrinsic factors and the population sizes of threatened birds
Attempts to explain the orders-of-magnitude variation observed in animal population sizes have principally focused on intrinsic differences between the taxa compared, but with limited success: most variation remains unexplained by such studies. However, animal population sizes may also vary in response to extrinsic factors, such as the environment occupied or the influence of human activities. Here, we use new estimates of the global population sizes of threatened bird species to examine extrinsic correlates of variation in their numbers, using general linear modelling and methods to control for phylogenetic relatedness. Threatened bird population sizes varied significantly with several extrinsic factors, including altitude, biogeographical region inhabited, type of extinction threat faced, and habitat used. They also vary with geographical range size, which was included in the analysis to control for its potentially confounding effects on the results. Details of the observed relationships, which vary with analytical method, are discussed. However, apart from geographical range size, none of the extrinsic variables analysed here explain more than a small percentage of the variation in threatened bird population sizes. Thus, it seems likely that a comprehensive explanation for why some species are common while others are rare will not be dominated by a single factor.
Abstract.
Petchey OL, Gaston KJ (2002). Functional diversity (FD), species richness and community composition.
Ecology Letters,
5(3), 402-411.
Abstract:
Functional diversity (FD), species richness and community composition
Functional diversity is an important component of biodiversity, yet in comparison to taxonomic diversity, methods of quantifying functional diversity are less well developed. Here, we propose a means for quantifying functional diversity that may be particularly useful for determining how functional diversity is related to ecosystem functioning. This measure of functional diversity "FD" is defined as the total branch length of a functional dendrogram. Various characteristics of FD make it preferable to other measures of functional diversity, such as the number of functional groups in a community. Simulating species' trait values illustrates how the relative importance of richness and composition for FD depends on the effective dimensionality of the trait space in which species separate. Fewer dimensions increase the importance of community composition and functional redundancy. More dimensions increase the importance of species richness and decreases functional redundancy. Clumping of species in trait space increases the relative importance of community composition. Five natural communities show remarkably similar relationships between FD and species richness.
Abstract.
Gaston KJ, Matter SF (2002). Individuals-area relationships: Comment. Ecology, 83(1), 288-293.
Gaston KJ, Blackburn TM (2002). Large-scale dynamics in colonization and extinction for breeding birds in Britain.
Journal of Animal Ecology,
71(3), 390-399.
Abstract:
Large-scale dynamics in colonization and extinction for breeding birds in Britain
1. A number of generalizations have been made as to the effects of the area of occupancy, population size, dispersal ability and body size of species on their relative rates of local colonization and extinction. 2. Here, data on the breeding bird assemblage of Britain are used to test these generalizations. The complete geographical ranges of British birds have been censused twice, in the periods 1968-72 and 1988-91, allowing rates of colonization and extinction between these periods to be estimated. 3. The local colonization dynamics of species are influenced independently by their range sizes and the dispersal abilities of adult birds: species with smaller range sizes and larger dispersal distances were more likely to have colonized new areas between the two census periods. 4. The local extinction dynamics of species are influenced independently by their population sizes and body masses: species with smaller population sizes and body sizes were more likely to have gone extinct from areas inhabited in the first census period. 5. These results remain when controlling for the effects of phylogenetic relatedness. 6. These analyses uphold many commonly held generalizations about the correlates of local colonization and extinction, and suggest that the long-term evolutionary history of these bird species has influenced their potential to respond to current ecological conditions.
Abstract.
Blackburn TM, Gaston KJ (2002). Macroecology is distinct from biogeography.
NATURE,
418(6899), 723-723.
Author URL.
Rodrigues ASL, Gaston KJ (2002). Maximising phylogenetic diversity in the selection of networks of conservation areas.
Biological Conservation,
105(1), 103-111.
Abstract:
Maximising phylogenetic diversity in the selection of networks of conservation areas
Phylogenetic diversity (PD) is a biodiversity measure that takes account of phylogenetic relationships (hence evolutionary history) between taxa. It may therefore provide a better currency for conservation evaluation than taxonomic richness. Here, we demonstrate that, contrary to recent assertions, optimisation tools can be used to maximise PD in the context of complementary reserve selection, and that the spatial overlap between sets of sites maximising genus diversity and PD cannot be used as evidence that the first measure is a good surrogate for the second. Nevertheless, in our own analyses using data on bird genera in northwest South Africa we found that near equally effective results are obtained in the selection of complementary sets of sites when maximising for each of these two measures of biodiversity. © 2002 Elsevier Science Ltd. All rights reserved.
Abstract.
Addo-Bediako A, Chown SL, Gaston KJ (2002). Metabolic cold adaptation in insects: a large-scale perspective.
Functional Ecology,
16(3), 332-338.
Abstract:
Metabolic cold adaptation in insects: a large-scale perspective
1. Despite its significance from both life-history and physiological perspectives, metabolic cold adaptation (MCA) in insects remains controversial. Although several smallscale studies have provided support for such adaptation, many others have not. 2. Using a global-scale analysis of the standard metabolic rates of 346 species, it is shown that after removing the effects of trial temperature and body mass, environmental temperature significantly influences interspecific variation in metabolic rate, such that insects from colder environments tend to have higher, whole-organism, metabolic rates. Although this effect is weak, it does provide evidence in favour of MCA in this important terrestrial group. 3. Although data from the Southern Hemisphere are limited, we show that this adaptation also takes the form of an increase in the slope of the metabolic rate-temperature relationship in Northern, but not in Southern, Hemisphere species. 4. Metabolic cold adaptation and its variation among the hemispheres should be counted among the causes of interspecific variation in metabolic rate.
Abstract.
McGeoch MA, Gaston KJ (2002). Occupancy frequency distributions: Patterns, artefacts and mechanisms.
Biological Reviews of the Cambridge Philosophical Society,
77(3), 311-331.
Abstract:
Occupancy frequency distributions: Patterns, artefacts and mechanisms
Numerous hypotheses have been proposed to explain the shape of occupancy frequency distributions (distributions of the numbers of species occupying different numbers of areas). Artefactual effects include sampling characteristics, whereas biological mechanisms include organismal, niche-based and metapopulation models. To date, there has been little testing of these models. In addition, although empirically derived occupancy distributions encompass an array of taxa and spatial scales, comparisons between them are often not possible because of differences in sampling protocol and method of construction. In this paper, the effects of sampling protocol (grain, sample number, extent, sampling coverage and intensity) on the shape of occupancy distributions are examined, and approaches for minimising artefactual effects recommended. Evidence for proposed biological determinants of the shape of occupancy distributions is then examined. Good support exists for some mechanisms (habitat and environmental heterogeneity), little for others (dispersal ability), while some hypotheses remain untested (landscape productivity, position in geographic range, range size frequency distributions), or are unlikely to be useful explanations for the shape of occupancy distributions (species specificity and adaptation to habitat, extinction-colonization dynamics). The presence of a core (class containing species with the highest occupancy) mode in occupancy distributions is most likely to be associated with larger sample units, and small homogenous sampling areas positioned well within and towards the range centers of a sufficient proportion of the species in the assemblage. Satellite (class with species with the lowest occupancy) modes are associated with sampling large, heterogeneous areas that incorporate a large proportion of the assemblage range. However, satellite modes commonly also occur in the presence of a core mode, and rare species effects are likely to contribute to the presence of a satellite mode at most sampling scales. In most proposed hypotheses, spatial scale is an important determinant of the shape of the observed occupancy distribution. Because the attributes of the mechanisms associated with these hypotheses change with spatial scale, their predictions for the shape of occupancy distributions also change. To understand occupancy distributions and the mechanisms underlying them, a synthesis of pattern documentation and model testing across scales is thus needed. The development of null models, comparisons of occupancy distributions across spatial scales and taxa, documentation of the movement of individual species between occupancy classes with changes in spatial scale, as well as further testing of biological mechanisms are all necessary for an improved understanding of the distribution of species and assemblages within their geographic ranges.
Abstract.
Holt AR, Gaston KJ, He F (2002). Occupancy-abundance relationships and spatial distribution: a review.
Basic and Applied Ecology,
3(1), 1-13.
Abstract:
Occupancy-abundance relationships and spatial distribution: a review
One of the most general patterns in community ecology is the positive relationship between the number of sites or areas in which a species in a taxonomic assemblage occurs regionally and its local abundance. A number of hypotheses have been proposed to explain this interspecific occupancy-abundance relationship, but it has recently been argued that the pattern is most profitably viewed as a consequence of the spatial distribution of the individuals of each species. In this paper we explore the link between spatial distribution and the occupancy-abundance relationship, with particular reference to statistical models that have been suggested to describe the pattern, and discuss its connections with a broad understanding of how organisms are distributed in space. A range of models describe observed occupancy-abundance relationships reasonably well, but are commonly not well differentiated over the range of abundances implicit in such relationships. There is little evidence that species exhibit great commonality in the form of their aggregative behaviour, but this does not matter in terms of the generation of a positive interspecific occupancy-abundance relationship.
Abstract.
He FL, Gaston KJ, Wu JG (2002). On species occupancy-abundance models.
ECOSCIENCE,
9(1), 119-126.
Author URL.
Rodrigues ASL, Gaston KJ (2002). Optimisation in reserve selection procedures - Why not?.
Biological Conservation,
107(1), 123-129.
Abstract:
Optimisation in reserve selection procedures - Why not?
Linear programming techniques provide an appropriate tool for solving reserve selection problems. Although this has long been known, most published analyses persist in the use of intuitive heuristics, which cannot guarantee the optimality of the solutions found. Here, we dispute two of the most common justifications for the use of intuitive heuristics, namely that optimisation techniques are too slow and cannot solve the most realistic selection problems. By presenting an overview of processing times obtained when solving a diversity of reserve selection problems, we demonstrate that most of those published could almost certainly be solved very quickly by standard optimisation software using current widely available computing technology. Even for those problems that take longer to solve, solutions with low levels of sub-optimality can be obtained quite quickly, presenting a better alternative to intuitive heuristics. © 2002 Elsevier Science Ltd. All rights reserved.
Abstract.
Gaston KJ, Pressey RL, Margules CR (2002). Persistence and vulnerability: retaining biodiversity in the landscape and in protected areas.
JOURNAL OF BIOSCIENCES,
27(4), 361-384.
Author URL.
Chown SL, Addo-Bediako A, Gaston KJ (2002). Physiological variation in insects: large-scale patterns and their implications.
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY,
131(4), 587-602.
Author URL.
Storch D, Gaston KJ, Cepák J (2002). Pink landscapes: 1/f spectra of spatial environmental variability and bird community composition.
Proc Biol Sci,
269(1502), 1791-1796.
Abstract:
Pink landscapes: 1/f spectra of spatial environmental variability and bird community composition.
Temporal and spatial environmental variability are predicted to have reddened spectra that reveal increases in variance with the period or length sampled. However, spectral analyses have seldom been performed on ecological data to determine whether these predictions hold true in the case of spatial environmental variability. For a 50 km long continuous transect of 128 point samples across a heterogeneous cultural landscape in the Czech Republic, both habitat composition and bird species composition decomposed by standard ordination techniques did indeed exhibit reddened spectra. The values of main ordination axes have relationships between log spectral density and log frequency with slopes close to -1, indicating 1/f, or 'pink' noise type of variability that is characterized by scale invariance. However, when habitat composition was controlled for and only residuals for bird species composition were analysed, the spectra revealed a peak at intermediate frequencies, indicating that population processes that structure bird communities but are not directly related to the structure of the environment might have some typical correlation length. Spatial variability of abundances of individual species was mostly reddened as well, but the degree was positively correlated to their total abundance and niche position (strength of species-habitat association). If 'pink' noise type of variability is as generally typical for spatial environmental variability as for temporal variability, the consequences may be profound for patterns of species diversity on different spatial scales, the form of species-area relationships and the distribution of abundances within species ranges.
Abstract.
Author URL.
Perez-Arteaga A, Gaston KJ, Kershaw M (2002). Population trends and priority conservation sites for Mexican Duck Anas diazi.
Bird Conservation International,
12(1), 35-52.
Abstract:
Population trends and priority conservation sites for Mexican Duck Anas diazi
Little is known about Mexican Duck Anas diazi biology and populations. We analyse long-term (1960-2000) trends of Mexican Duck numbers in Mexico and employ contemporary count data (1991-2000) from the U.S. Fish and Wildlife Service midwinter surveys to identify key sites for conservation using a complementarity approach. The overall Mexican Duck population showed a significant long-term increase of 2.5% per year, with large fluctuations throughout the study period. The Northern highlands population increased at an annual rate of 7.7%, while the Central highlands population showed no significant long-term trend. During the last decade, counts in both the Northern and Central highlands exhibited no significant change. At the site level, significant long-term increases occurred in four localities in the Northern highlands (Laguna BabPcora +13.9% annually, Laguna Bustillos +25.9%, Laguna Mexicanos +20.4% and Laguna Santiaguillo +16.9%) and in three localities in the Central highlands (Languillo +15.3% annually, Presa Solis +8.9%, Zacapu +13.4%). Two sites in the Central highlands showed significant declines, in the long term (Lago de Chapala, -5.2% per year) and during the last decade (Lerma, -11.8% per year). The Northern highlands held 16% and the Central highlands 84% of the Mexican Duck population in the period 1960-2000; during the last decade, these figures were 31% and 69%, respectively. A set of priority sites for conservation of the Mexican Duck was identified, consisting of 15 sites holding more than 70% of the midwinter Mexican Duck counts in Mexico. Ten sites from the priority set also qualify for designation as wetlands of international importance under the Ramsar Convention on Wetlands, by holding ≥ 1% of the estimated population. Four of the priority sites are in the Northern highlands and 11 in the Central highlands, of which eight are distributed along the Rio Lerma drainage. The most urgent actions that need to be undertaken are to estimate the current minimum population size in Mexico; to establish a programme for monitoring populations in the priority sites, especially those located within the highly degraded Rio Lerma drainage; and to determine the most feasible management actions for the species, concentrating efforts around the priority sites.
Abstract.
Rodrigues ASL, Gaston KJ (2002). Rarity and conservation planning across geopolitical units.
Conservation Biology,
16(3), 674-682.
Abstract:
Rarity and conservation planning across geopolitical units
Conservation planning is usually done within geopolitical units that tend to encompass only part of the geographic range of most species. Consequently, the relative rarity of a species within the study area considered does not necessarily reflect its relative global rarity or its conservation relevance. We investigated the implications of species' rarity in complementary reserve selection across geopolitical boundaries based on data on the distribution of birds in southern Africa. Our results demonstrate that restricted-range species have a disproportionate effect on the number and identity of the cells selected by complementarity. The most extreme situation occurs when species whose ranges occupy single cells impose the selection of those particular sites as irreplaceable cells. Not all restricted-range species are equally important. Some are "apparent rarities" in the study area because they are vagrants, occur very marginally to their range, or have been introduced, and these are mainly irrelevant to conservation planning in a region. Filtering rare nontarget species from the data before reserve selection results in a significant increase in the efficiency of minimum complementary sets. It is particularly recommended for taxa with high mobility, in which vagrancy is more likely. Dividing the study area into geopolitical units has a profound effect on the sites selected by complementarity. It results in loss of overall efficiency, in a tendency for selection of sites at the periphery of the units, and in some species receiving more protection at the edge of their ranges than at the center. Geopolitical coordination in conservation planning may not only result in improved overall efficiency but also a better allocation of resources that improves the long-term robustness of reserve networks.
Abstract.
Blackburn TM, Gaston KJ (2002). Scale in macroecology.
Global Ecology and Biogeography,
11(3), 185-189.
Abstract:
Scale in macroecology
The past 15 years have seen the development of macroecology as a respectable discipline within the biological sciences. Initial concerns about the utility of a large-scale approach to ecology have been quietened, if not eliminated, but other arguments about spatial scale in ecology have arisen to take their place. The situation has moved from the absolute advocacy of small-scale over large-scale studies to an advocacy of some large scales in preference to others. Here, we argue that there is no general sense in which one scale of study (either in terms of spatial extent or sampling resolution) is better than any other. As long as there are sensible reasons for using the scale chosen, studies at all scales have the potential to inform about the structure and function of the ecological systems that clothe this planet.
Abstract.
van Rensburg BJ, Chown SL, Gaston KJ (2002). Species richness, environmental correlates, and spatial scale: a test using South African birds.
AMERICAN NATURALIST,
159(5), 566-577.
Author URL.
Jones AG, Chown SL, Gaston KJ (2002). Terrestrial invertebrates of Gough Island: an assemblage under threat?.
African Entomology,
10(1), 83-91.
Abstract:
Terrestrial invertebrates of Gough Island: an assemblage under threat?
The natural communities of Gough Island have the reputation of being amongst the most pristine of any cool-temperate oceanic island. However, Gough Island is relatively depauperate in indigenous invertebrates, and preliminary results of an ongoing terrestrial invertebrate survey have shown that introduced species now equal, or exceed, the numbers of indigenous species in many groups. Furthermore, many of these introductions are likely to have occurred within the last 50 years. Such high rates of recent introductions constitute a significant conservation threat to the indigenous invertebrates and the island's biodiversity as a whole. In addition, endemic invertebrate species are amongst the prey of a non-invertebrate introduction, the house mouse (Mus musculus Linn.). In this paper, we review the present knowledge of the invertebrates of Gough, report on the preliminary observations of the ongoing Gough Island Terrestrial Invertebrate Survey, and discuss the implications of introduced species for the conservation of Gough Island's indigenous species.
Abstract.
Gaston KJ, He F (2002). The distribution of species range size: a stochastic process.
Proc Biol Sci,
269(1495), 1079-1086.
Abstract:
The distribution of species range size: a stochastic process.
The major role played by environmental factors in determining the geographical range sizes of species raises the possibility of describing their long-term dynamics in relatively simple terms, a goal which has hitherto proved elusive. Here we develop a stochastic differential equation to describe the dynamics of the range size of an individual species based on the relationship between abundance and range size, derive a limiting stationary probability model to quantify the stochastic nature of the range size for that species at steady state, and then generalize this model to the species-range size distribution for an assemblage. The model fits well to several empirical datasets of the geographical range sizes of species in taxonomic assemblages, and provides the simplest explanation of species-range size distributions to date.
Abstract.
Author URL.
Brewer AM, Gaston KJ (2002). The geographical range structure of the holly leaf-miner. I. Population density.
Journal of Animal Ecology,
71(1), 99-111.
Abstract:
The geographical range structure of the holly leaf-miner. I. Population density
1. The local population density structure of a phytophagous insect, the holly leaf-miner Phytomyza ilicis Curtis, was examined across its natural geographical range in Europe. 2. The frequency distribution of the number of sample sites at which the leaf-miner attained different densities per tree was strongly right-skewed, with the species being absent from a large number of sites at which its host occurred, particularly in southern regions. 3. There was a decline in the spatial autocorrelation of leaf-miner densities with increasing distance between sample sites, with negative autocorrelation at long lags resulting in part from high densities being attained at the north-eastern range limits and low densities at the southern range limits. 4. Partial regression analysis was used to model leaf-miner densities in terms of spatial position within the geographical range and the broad climate experienced at the sample localities. This accounted for between 40 and 65% of the variation in densities, dependent upon how the leaf-miner's geographical range was defined. 5. While overall these results are at odds with common and intuitively appealing assertions about the abundance structure of geographical ranges, they can readily be interpreted in terms of a simple modification of a general model of such structures.
Abstract.
Holt AR, Warren PH, Gaston KJ (2002). The importance of biotic interactions in abundance-occupancy relationships.
Journal of Animal Ecology,
71(5), 846-854.
Abstract:
The importance of biotic interactions in abundance-occupancy relationships
1. Metapopulation dynamics have been postulated as a possible mechanism giving rise to positive interspecific relationships between local abundance and regional occupancy. These may operate through the carrying capacity or the rescue effect hypotheses. However, both are based on single species models that sum independent occurrences of species to form an assemblage, ignoring interspecific interactions. 2. Here we test experimentally whether interspecific interactions and dispersal influence the formation of the abundance-occupancy relationship in metapopulation systems in laboratory microcosms containing protists and bacteria. 3. The effect of species interactions was tested by comparison of the abundance-occupancy relationship in multiple habitat patch systems containing all species together, with the relationship formed by combining data from equivalent systems containing each protist species alone. 4. Abundance-occupancy relationships in interacting communities were better defined than those in non-interacting communities. The inclusion of interspecific interactions was found to cause a reduction in the abundance and occupancy of the majority of species, as a consequence of which the position of species within the relationship changed drastically.
Abstract.
Koleff P, Gaston KJ (2002). The relationships between local and regional species richness and spatial turnover.
Global Ecology and Biogeography,
11(5), 363-375.
Abstract:
The relationships between local and regional species richness and spatial turnover
Aim to determine the empirical relationships between species richness and spatial turnover in species composition across spatial scales. These have remained little explored despite the fact that such relationships are fundamental to understanding spatial diversity patterns. Location South-east Scotland. Methods Defining local species richness simply as the total number of species at a finer resolution than regional species richness and spatial turnover as turnover in species identity between any two or more areas, we determined the empirical relationships between all three, and the influence of spatial scale upon them, using data on breeding bird distributions. We estimated spatial turnover using a measure independent of species richness gradients, a fundamental feature which has been neglected in theoretical studies. Results Local species richness and spatial turnover exhibited a negative relationship, which became stronger as larger neighbourhood sizes were considered in estimating the latter. Spatial turnover and regional species richness did not show any significant relationship, suggesting that spatial species replacement occurs independently of the size of the regional species pool. Local and regional species richness only showed the expected positive relationship when the size of the local scale was relatively large in relation to the regional scale. Conclusions Explanations for the relationships between spatial turnover and local and regional species richness can be found in the spatial patterns of species commonality, gain and loss between areas.
Abstract.
Bonn A, Rodrigues ASL, Gaston KJ (2002). Threat and endemism: good indicators of patterns of biodiversity on a national scale?.
AVIAN LANDSCAPE ECOLOGY: PURE AND APPLIED ISSUES IN THE LARGE-SCALE ECOLOGY OF BIRDS, 281-281.
Author URL.
Bonn A, Rodrigues ASL, Gaston KJ (2002). Threatened and endemic species: Are they good indicators of patterns of biodiversity on a national scale?.
Ecology Letters,
5(6), 733-741.
Abstract:
Threatened and endemic species: Are they good indicators of patterns of biodiversity on a national scale?
Endemic and/or threatened species are often targeted to set conservation priorities. It is tempting to assume that a reserve network focusing on these species will be an effective umbrella for overall species richness of a country. For South Africa and Lesotho we tested whether complementary networks selected for threatened and/or endemic bird species satisfactorily represent all bird species, both in terms of capturing areas where other species are present or areas where they are more abundant (and, presumably, more viable). We found that areas selected for threatened and endemic species perform considerably better than areas selected at random. However, they do not guarantee the representation of overall bird species diversity, particularly not in peak abundance locations. Although nationally threatened and endemic species are important conservation targets, our results indicate that reserve networks focusing solely on these species may not be sufficient to preserve overall species diversity in a country.
Abstract.
Pérez-Arteaga A, Gaston KJ, Kershaw M (2002). Undesignated sites in Mexico qualifying as wetlands of international importance.
Biological Conservation,
107(1), 47-57.
Abstract:
Undesignated sites in Mexico qualifying as wetlands of international importance
Those sites designated under the Ramsar Convention on Wetlands of International Importance especially as Waterfowl Habitat constitute the most important wetland conservation network at a global level, with more than 1000 sites of international importance. With only seven designated sites, waterfowl and wetlands in Mexico are evidently under-represented in the list. We identify 34 currently undesignated sites in Mexico that qualify as wetlands of international importance, based on waterfowl count data from 1991-1997, using the Ramsar Convention criteria based on waterfowl. Using a complementarity approach implemented by linear integer programming, the sites were prioritised into two categories on the basis of their importance for designation. Twelve sites were categorised as Priority 1 (higher), and 22 sites as Priority 2 (lower). The Priority 1 set has held a waterfowl count average of 1.2 million individuals, and between 1% (ruddy duck, Oxyura j. jamaicensis) and 51% (black brant, Branta bernicla nigricans) of the populations of 10 species of waterfowl, and includes sites from eight biogeographic regions. © 2002 Elsevier Science Ltd. All rights reserved.
Abstract.
Gaston KJ (2002). World Atlas of biodiversity: Earth's living resources in the 21st century.
NATURE,
419(6907), 562-+.
Author URL.
James A, Gaston KJ, Balmford A (2001). Can we afford to conserve biodiversity?. BioScience, 51(1), 43-52.
Gaston KJ, Rodrigues ASL, Van Rensburg BJ, Koleff P, Chown SL (2001). Complementary representation and zones of ecological transition.
Ecology Letters,
4(1), 4-9.
Abstract:
Complementary representation and zones of ecological transition
Minimum complementary sets of sites that represent each species at least once have been argued to provide a nominal core reserve network and the starting point for regional conservation programs. However, this approach may be inadequate if there is a tendency to represent several species at marginal areas within their ranges, which may occur if high efficiency results from preferential selection of sites in areas of ecological transition. Here we use data on the distributions of birds in South Africa and Lesotho to explore this idea. We found that for five measures that are expected to reflect the location of areas of ecological transition, complementary sets tend to select higher values of these measures than expected by chance. We recommend that methods for the identification of priority areas for conservation that incorporate viability concerns be preferred to minimum representation sets, even if this results in more costly reserve networks.
Abstract.
Cowley MJR, Thomas CD, Roy DB, Wilson RJ, León-Cortés JL, Gutiérrez D, Bulman CR, Quinn RM, Moss D, Gaston KJ (2001). Density-distribution relationships in British butterflies I: the effect of mobility and spatial scale. Journal of Animal Ecology, 70, 410-425.
Rodrigues ASL, Gaston KJ (2001). How large do reserve networks need to be?.
Ecology Letters,
4(6), 602-609.
Abstract:
How large do reserve networks need to be?
Reserve networks are essential for the long-term persistence of biodiversity. To fulfil this goal, they need not only to represent all species to be conserved but also to be sufficiently large to ensure species' persistence over time. An extensive literature exists on the required size of individual reserves, but to date there has been little investigation regarding the appropriate size of entire networks. The IUCN's proposal that 10% of each nation be reserved is often presented as a desirable target, but concerns have been raised that this is insufficient and is dictated primarily by considerations of feasibility and politics. We found that the minimum percentage of area needed to represent all species within a region increases with the number of targeted species, the size of selection units, and the level of species' endemism. This has important implications for conservation planning. First, no single universal target is appropriate, as ecosystems or nations with higher diversity and/or higher levels of endemism require substantially larger fractions of their areas to be protected. Second, a minimum conservation network sufficient to capture the diversity of vertebrates is not expected to be effective for biodiversity in general. Third, the 10% target proposed by the IUCN is likely to be wholly insufficient, and much larger fractions of area are estimated to be needed, especially in tropical regions.
Abstract.
Koleff P, Gaston KJ (2001). Latitudinal gradients in diversity: Real patterns and random models.
Ecography,
24(3), 341-351.
Abstract:
Latitudinal gradients in diversity: Real patterns and random models
Mid-domain models have been argued to provide a default explanation for the best known spatial pattern in biodiversity, namely the latitudinal gradient in species richness, These models assume no environmental gradients, but merely a random latitudinal association between the size and placement of the geographic ranges of species. A mid-domain peak in richness is generated because when the latitudinal extents of species in a given taxonomic group are bounded to north and south, perhaps by a physical constraint such as a continental edge or perhaps by a climatic constraint such as a critical temperature or precipitation threshold, then the number of ways in which ranges can be distributed changes systematically between the bounds. In addition, such models make predictions about latitudinal variation in the latitudinal extents of the distributions of species, and in beta diversity (the spatial turnover in species identities). Here we test how well five mid-domain models predict observed latitudinal patterns of species richness, latitudinal extent and beta diversity in two groups of birds, parrots and woodpeckers, across the New World. Whilst both groups exhibit clear gradients in richness and beta diversity and the general trend in species richness is acceptably predicted (but not accurately, unless substantial empirical information is assumed), the fit of these models is uniformly poor for beta diversity and latitudinal range extent. This suggests either that, at least for these data, as presently formulated mid-domain models are too simplistic, or that in practice the mid-domain effect is not significant in determining geographical variation in diversity.
Abstract.
Blackburn TM, Gaston KJ (2001). Linking patterns in macroecology.
Journal of Animal Ecology,
70(2), 338-352.
Abstract:
Linking patterns in macroecology
1. Associated with the development of the field of macroecology has been the recognition and analysis of a number of different patterns in the large-scale abundance and distribution of species. The mechanistic bases of these patterns have usually been considered in isolation, yet the patterns are necessarily linked, as the same individual animals contribute to all of them. 2. Here, a model linking macroecological patterns in abundance, distributional extent and body mass is developed, based on how the finite amount of energy available to the species in a region is divided between them. The energy available to a species is assumed to support some quantity of biomass, which must then be allocated to either many small-bodied or fewer larger-bodied individuals. This identifies a necessary link between population size and body mass, which predicts when the variety of relationships between these variables in the published literature are expected to occur. 3. Although framed in terms of energy use by species, the model does not assume that energy per se is necessarily limiting populations. How individuals use space determines the form of relationships between population size and distributional extent, distributional extent and body mass, and population density and body mass. The model additionally allows a number of falsifiable predictions about the anatomy of macroecological patterns. 4. Support for the assumptions of the model is discussed.
Abstract.
Blackburn TM, Gaston KJ (2001). Local avian assemblages as random draws from regional pools.
Ecography,
24(1), 50-58.
Abstract:
Local avian assemblages as random draws from regional pools
It is becoming increasingly apparent that the ecological structure of local assemblages depends to some degree on the regional context within which they are embedded. Here, the structure of one such local assemblage, the avifauna of Eastern Wood, southern England, is modelled as a random draw from the pool of British deciduous woodland species. The random draw model accurately predicts most (> 90%) of a suite of descriptive statistics calculated from the Eastern Wood avifauna, when the probability that a species is selected for inclusion in a random assemblage is weighted by its British geographic range size. Models for which a species selection is weighted by its British population size, or is unweighted, perform less well. This suggests that how widespread a species is in a region affects the likelihood that it will occur at any given local site, and hence that large-scale patterns in the distribution of species can strongly influence the composition and structure of local assemblages.
Abstract.
Blackburn TM, Gaston KJ, Duncan RP (2001). Population density and geographical range size in the introduced and native passerine faunas of New Zealand.
Diversity and Distributions,
7(5), 209-221.
Abstract:
Population density and geographical range size in the introduced and native passerine faunas of New Zealand
The current avifauna of New Zealand comprises species with two distinct origins: those that evolved in New Zealand or colonized naturally from neighbouring landmasses, and those that were deliberately introduced to the islands by European settlers. Elsewhere, it has been shown that for species introduced to New Zealand from Britain there is a positive interspecific correlation between the geographical range sizes attained in both countries. Since positive relationships between abundance, measured either as population size or density, and geographical range size are a near ubiquitous feature of assemblages of closely related animal species, this suggests that species' abundances may also be so correlated between the two countries. Here, data for 12 passerine bird species introduced to New Zealand from Britain are used to compare population densities and density-range size relationships in their native and alien ranges. In addition, the density-range size relationship for 12 passerine bird species that can be considered native to New Zealand is compared to that for the introduced species. The geographical range size and the mean and maximum densities of introduced species in New Zealand were significantly positively correlated with those values for the same species in Britain. However, in no case was the relationship between mean density and range size significant. While not statistically significant, density-range size relationships for introduced species are similar in New Zealand and Britain, but those for introduced and native species in New Zealand are quite different. Implications of these patterns are discussed.
Abstract.
Addo-Bediako A, Chown SL, Gaston KJ (2001). Revisiting water loss in insects: a large scale view.
Journal of Insect Physiology,
47(12), 1377-1388.
Abstract:
Revisiting water loss in insects: a large scale view
Desiccation resistance in insects has long been thought to covary with environmental water availability, and to involve changes in both cuticular and respiratory transpiration. Here, we adopt a large-scale approach to address both issues. Water loss rate and precipitation are positively related at global scales, a significant proportion (68%) of the interspecific variation in water loss rate is explained at the genus level or above. The relationship between metabolic rate and water loss rate differs substantially between mesic and xeric species. While these variables covary as a consequence of their independent covariation with body mass in mesic species, this is not the case in xeric species. In the latter, there is a strong relationship between the residuals of the water loss rate-body mass and metabolic rate-body mass relationships, and water loss rate is much reduced. Moreover, because metabolic rate does not differ significantly between xeric and mesic species of a similar size, respiratory transpiration constitutes a greater proportion of total water loss in xeric than in mesic species of a similar size. This implies that respiratory transpiration and the extent to which it can be modified must be of considerable importance in xeric insect species, although finer scale studies suggest otherwise. © 2001 Elsevier Science Ltd. All rights reserved.
Abstract.
Gaston KJ, Chown SL, Mercer RD (2001). The animal species-body size distribution of Marion Island.
Proc Natl Acad Sci U S A,
98(25), 14493-14496.
Abstract:
The animal species-body size distribution of Marion Island.
Body size is one of the most significant features of animals. Not only is it correlated with many life history and ecological traits, but it also may influence the abundance of species within, and their membership of, assemblages. Understanding of the latter processes is frequently based on a comparison of model outcomes with the frequency of species of different body mass within natural assemblages. Consequently, the form of these frequency distributions has been much debated. Empirical data usually concern taxonomically delineated groups, such as classes or orders, whereas the processes ultimately apply to whole assemblages. Here, we report the most complete animal species-body size distribution to date for those free-living species breeding on sub-Antarctic Marion Island and using the terrestrial environment. Extending over 15 orders of magnitude of variation in body mass, this distribution is bimodal, with separate peaks for invertebrates and vertebrates. Under logarithmic transformation, the distribution for vertebrates is not significantly skewed, whereas that for invertebrates is right-skewed. Contrary to expectation based on a fractal or pseudofractal environmental structure, the decline in the richness of species at the smallest body sizes is a real effect and not a consequence of unrecorded species or of species introductions to the island. The scarcity of small species might well be a consequence of their large geographic ranges.
Abstract.
Author URL.
Lennon JJ, Koleff P, Greenwood JJD, Gaston KJ (2001). The geographical structure of British bird distributions: diversity, spatial turnover and scale.
JOURNAL OF ANIMAL ECOLOGY,
70(6), 966-979.
Author URL.
Gaston KJ, Spicer JI (2001). The relationship between range size and niche breadth: a test using five species of Gammarus (Amphipoda).
Global Ecology and Biogeography,
10(2), 179-188.
Abstract:
The relationship between range size and niche breadth: a test using five species of Gammarus (Amphipoda)
Data for five closely related species of gammarid crustaceans are used to examine interspecific relationships between the breadth of fundamental tolerance or capacity and geographical range size. Gammarus duebeni is, almost without exception, the most tolerant species and that with the best physiological performance. Although there is some limited variation, the remaining species can be ranked broadly in the sequence G. zaddachi > G. salinus > G. oceanicus > G. locusta. The wide tolerance and high performance of G. duebeni is associated with the occupation of a wider range of environmental 'types' than any other of the species. In terms of geographical range size, the species can be ranked from most to least widespread in the sequence G. oceanicus > G. duebeni > G. zaddachi > G. salinus > G. locusta. This provides little support for Brown's hypothesis, or the argument that the more widely distributed species within a taxonomic assemblage also tend to have the widest fundamental niches. However, if marine (G. oceanicus and G. locusta) and estuarine (G. duebeni, G. zaddachi, G. salinus) species are considered separately, then in each case the species with the largest geographical range is also the most tolerant/best performer. In this sense, the jack-of-all-trades is the master-of-all, rather than the master-of-none.
Abstract.
Williamson M, Gaston KJ, Lonsdale WM (2001). The species-area relationship does not have an asymptote!.
Journal of Biogeography,
28(7), 827-830.
Abstract:
The species-area relationship does not have an asymptote!
Aim: to attack a widespread myth. Location: World-wide. Methods: Simple mathematical logical and empirical examples. Results: As both species and area are finite and non-negative, the species-area relationship is limited at both ends. The log species-log area relationship is normally effectively linear on scales from about 1 ha to 107 km2. There are no asymptotes. At the intercontinental scale it may get steeper; at small scales it may in different cases get steeper or shallower or maintain its slope. Main conclusion: the species-area relationship does not have an asymptote.
Abstract.
Chown SL, Rodrigues ASL, Gremmen NJM, Gaston KJ (2001). World heritage status and conservation of Southern ocean Islands. Conservation Biology, 15(3), 550-557.
Gaston KJ, Blackburn TM, Greenwood JJD, Gregory RD, Quinn RM, Lawton JH (2000). Abundance-occupancy relationships.
Journal of Applied Ecology,
37(SUPPL. 1), 39-59.
Abstract:
Abundance-occupancy relationships
1. The abundance and distribution of species tend to be linked, such that species declining in abundance often tend also to show declines in the number of sites they occupy, while species increasing in abundance tend also to be increasing in occupancy. Therefore, intraspecific abundance-occupancy relationships are commonly positive. 2. The intraspecific pattern is mirrored by more general positive interspecific abundance-occupancy relationships: widespread species tend to be abundant, and narrowly distributed species rare. 3. Here, we review recent research on these patterns based on the flora and fauna of the British Isles. We assess their generality, describe what is currently known about their structure, and summarize the results of tests of the several hypotheses proposed to explain their existence. 4. The positive form generally exhibited by abundance-occupancy relationships, intraspecific or interspecific, has consequences for several areas of applied ecology, including conservation, harvesting, biological invasions and biodiversity inventorying. These implications are discussed briefly.
Abstract.
Chown SL, Gaston KJ (2000). Areas cradles and museums: the latitudinal gradient in species richness.
Trends in Ecology and Evolution,
15(8), 311-315.
Abstract:
Areas cradles and museums: the latitudinal gradient in species richness
Although numerous factors are postulated to be responsible for the gradient of increasing taxon richness towards lower latitudes, it has recently been suggested that the primary determinant is geographic area. This area model is appealing in its logic, but there is little empirical evidence to support it and several other mechanisms might also interact to obscure its effects. Nonetheless, the model has highlighted several fundamental issues concerning range size, speciation and extinction that, despite their considerable significance, remain poorly understood.
Abstract.
Gaston KJ (2000). Biodiversity: Higher taxon richness. Progress in Physical Geography, 24(1), 117-127.
McGeoch MA, Gaston KJ (2000). Edge effects on the prevalence and mortality factors of Phytomyza ilicis (Diptera, Agromyzidae) in a suburban woodland.
Ecology Letters,
3(1), 23-29.
Abstract:
Edge effects on the prevalence and mortality factors of Phytomyza ilicis (Diptera, Agromyzidae) in a suburban woodland
Although the effects of edges on the biotas of habitat patches have been widely discussed, there have been few empirical studies of the mechanistic basis of population and community differences between patch edges and interiors. This is particularly true of differential effects of edges on species' mortalities, and on interactions in insect populations and communities. Here we examine edge-associated differences in the prevalence and mortality factors of the holly leaf-miner Phytomyza ilicis, in a suburban woodland in Sheffield, U.K. Leaf miner prevalence was higher and survivorship to adulthood lower at the woodland edge. Natural enemies and other mortality factors contributed differently to total mortality at the edge and interior. Mechanisms underlying edge effects on P. ilicis arose from the interaction between microclimate, adult movement and host-plant quality. The differential induction of species mortality found, confirms the complexity of species' responses to habitat edges and the importance of understanding the effects of edges on species interactions.
Abstract.
He FL, Gaston KJ (2000). Estimating species abundance from occurrence.
AMERICAN NATURALIST,
156(5), 553-559.
Author URL.
Gregory RD, Gaston KJ (2000). Explanations of commonness and rarity in british breeding birds: Separating resource use and resource availability.
Oikos,
88(3), 515-526.
Abstract:
Explanations of commonness and rarity in british breeding birds: Separating resource use and resource availability
Two of the most prominent explanations for a positive interspecific relationship between local abundance and regional distribution are the resource breadth and the resource availability hypotheses. Here we test these hypotheses by characterising habitat use of British breeding birds using extensive census and environmental data. A group of 85 bird species was considered for study along with 34 land use or environmental variables, which were used to generate four ordination axes by Canonical Correspondence Analysis. Measures of niche breadth and position were derived from these synthetic environmental axes using standard procedures. Across species, none of five measures of abundance and distribution chosen were correlated with niche breadth, whereas four out of five of these measures were correlated negatively with niche position. Repeating the analyses using a method designed to control for phylogenetic non-independence confirmed these general patterns. Birds that tended to use resources that were more atypical of the environment tended to be rarer and thinly distributed, while those using typical resources were common and widely distributed. Performing the analyses on subsets of the data based on species sample sizes did not alter the conclusions. On the assumption that our analyses properly capture patterns of niche use by birds, we find little support for the resource breadth hypothesis, but considerable support for the resource availability hypothesis.
Abstract.
Rodrigues AS, Cerdeira JO, Gaston KJ (2000). Flexibility, efficiency, and accountability: Adapting reserve selection algorithms to more complex conservation problems.
Ecography,
23(5), 565-574.
Abstract:
Flexibility, efficiency, and accountability: Adapting reserve selection algorithms to more complex conservation problems
Flexibility, efficiency and accountability are considered key attributes of good reserve selection methods. Flexibility, the ability to incorporate all the diversity of considerations, concerns and information that typically impinge on real conservation problems, is fundamental if the particulars of any given situation are to be addressed and land use conflicts are to be effectively resolved. High efficiency, the representation of the maximum diversity of the relevant features (e.g. species) at the minimum cost, is important because reserves will commonly be in direct competition with other forms of land use. Accountability means that the solutions are obtained in a transparent way, allowing others to understand why and how the result was arrived at. Because of the robustness of the general integer linear model, a remarkably rich variety of problems concerning the management and efficient use of scarce resources can be represented as problems of this type. This study starts by analysing a simple representation problem and then develops more general problems that can be applied to a variety of conservation planning exercises. It is illustrated how high flexibility can be attained, while simultaneously addressing efficiency and accountability, by modelling reserve selection questions as integer linear problems.
Abstract.
Webb TJ, Gaston KJ (2000). Geographic range size and evolutionary age in birds.
Proc Biol Sci,
267(1455), 1843-1850.
Abstract:
Geographic range size and evolutionary age in birds.
Together with patterns of speciation and extinction, post-speciation transformations in the range sizes of individual species determine the form of contemporary species range-size distributions. However, the methodological problems associated with tracking the dynamics of a species' range size over evolutionary time have precluded direct study of such range-size transformations, although indirect evidence has led to several models being proposed describing the form that they might take. Here, we use independently derived molecular data to estimate ages of species in six monophyletic groups of birds, and examine the relationship between species age and global geographic range size. We present strong evidence that avian range sizes are not static over evolutionary time. In addition, it seems that, with the regular exception of certain taxa (for example island endemics and some threatened species), range-size transformations are non-random in birds. In general, range sizes appear to expand relatively rapidly post speciation; subsequently; and perhaps more gradually, they then decline as species age. We discuss these results with reference to the various models of range-size dynamics that have been proposed.
Abstract.
Author URL.
Gaston KJ (2000). Global patterns in biodiversity.
Nature,
405(6783), 220-227.
Abstract:
Global patterns in biodiversity.
To a first approximation, the distribution of biodiversity across the Earth can be described in terms of a relatively small number of broad-scale spatial patterns. Although these patterns are increasingly well documented, understanding why they exist constitutes one of the most significant intellectual challenges to ecologists and biogeographers. Theory is, however, developing rapidly, improving in its internal consistency, and more readily subjected to empirical challenge.
Abstract.
Author URL.
Chown SL, Gaston KJ, Hanel C (2000). Gough Island biodiversity study goes ahead.
SOUTH AFRICAN JOURNAL OF SCIENCE,
96(1), 7-8.
Author URL.
Balmford A, Gaston KJ, Rodrigues ASL, James A (2000). Integrating costs of conservation into international priority setting. Conservation Biology, 14(3), 597-605.
Chown SL, Gaston KJ (2000). Island-hopping invaders hitch a ride with tourists in South Georgia [1]. Nature, 408(6813).
Mace GM, Balmford A, Boitani L, Cowlishaw G, Dobson AP, Faith DP, Gaston KJ, Humphries CJ, Vane-Wright RI, Williams PH, et al (2000). It's time to work together and stop duplicating conservation efforts. [1]. Nature, 405(6785).
He F, Gaston KJ (2000). Occupancy-abundance relationships and sampling scales.
Ecography,
23(4), 503-511.
Abstract:
Occupancy-abundance relationships and sampling scales
The area of occupancy of a species and its abundance are dependent on the spatial scale at which they are measured. However, it is less obvious how the scale of sampling affects their correlation. This study investigated and modeled the effects of sampling unit size and areal extent on the interspecific occupancy-abundance relationships for a tropical tree species assemblage at a local scale and a temperate bird species assemblage at a regional scale. The results showed that both sampling unit size and study extent had profound quantitative effects on the occupancy-abundance relationship, although it remained positive. Several properties of the occupancy-abundance relationship can result from the effects of scale: 1) the linearity of the relationship decreases with the increase of sampling unit size; 2) for a given abundance, the area of occupancy increases with sampling unit size; and 3) variation in the area of occupancy increases with the increase of both sampling unit size and extent, and if the extent is large enough may be sufficient that no occupancy-abundance relationship is observed. Although the occupancy-abundance relationship can be satisfactorily modeled, the parameters depend on the scale used. This suggests that a model derived from one scale cannot be applied to another. In other words, to estimate the rarity or commonness of species using such a model, the estimation must be strictly done using the same sampling scale for all the species.
Abstract.
Chown SL, Gaston KJ (2000). Rapoport effect and speciation/extinction rates in the tropics - Reply.
TRENDS IN ECOLOGY & EVOLUTION,
15(12), 514-515.
Author URL.
Rodrigues AS, Gregory RD, Gaston KJ (2000). Robustness of reserve selection procedures under temporal species turnover.
Proc Biol Sci,
267(1438), 49-55.
Abstract:
Robustness of reserve selection procedures under temporal species turnover.
Complementarity-based algorithms for the selection of reserve networks emphasize the need to represent biodiversity features efficiently, but this may not be sufficient to maintain those features in the long term. Here, we use data from the Common Birds Census in Britain as an exemplar data set to determine guidelines for the selection of reserve networks which are more robust to temporal turnover in features. The extinction patterns found over the 1981-1991 interval suggest that two such guidelines are to represent species in the best sites where they occur (higher local abundance) and to give priority to the rarer species. We tested five reserve selection strategies, one which finds the minimum representation set and others which incorporate the first or both guidelines proposed. Strategies were tested in terms of their efficiency (inversely related to the total area selected) and effectiveness (inversely related to the percentage of species lost) using data on eight pairs of ten-year intervals. The minimum set strategy was always the most efficient, but suffered higher species loss than the others, suggesting that there is a trade-off between efficiency and effectiveness. A desirable compromise can be achieved by embedding the concerns about the long-term maintenance of the biodiversity features of interest in the complementarity-based algorithms.
Abstract.
Author URL.
Metcalfe JA, Marcal JAG, Gaston KJ (2000). The holly leaf miner as a study organism.
Journal of Biological Education,
34(2), 90-94.
Abstract:
The holly leaf miner as a study organism
The dipteran Phytomyza ilicis (the holly leaf miner) is a useful subject for practical work aimed at teaching life cycles, mortality factors, and population dynamics. It is found widely throughout most of Britain and its density varies both regionally and locally. It has a simple life history, in which eggs are laid in June on new holly leaves, larvae form mines in late summer onwards, pupate in early spring, and adults emerge in May and June. Mortality factors, such as parasitism and bird predation, operate at different stages of the holly leaf miner's life cycle, and their relative impacts can be assessed from single collections of mined leaves harvested from July through to November, after the insect's life cycle is completed. The holly leaf miner system has provided Open University students, studying the Science Foundation Course throughout Britain, with practical experience of studying living organisms in the field. Students examined a sample of mines and calculated the relative magnitudes of different fates. The frequency and type of error which students made in scoring the fates of the miners were quantified. The lessons learnt from the use of the holly leaf miner system as a subject for practical work are reported.
Abstract.
Addo-Bediako A, Chown SL, Gaston KJ (2000). Thermal tolerance, climatic variability and latitude.
Proceedings of the Royal Society B: Biological Sciences,
267(1445), 739-745.
Abstract:
Thermal tolerance, climatic variability and latitude
The greater latitudinal extents of occurrence of species towards higher latitudes has been attributed to the broadening of physiological tolerances with latitude as a result of increases in climatic variation. While there is some support for such patterns in climate, the physiological tolerances of species across large latitudinal gradients have seldom been assessed. Here we report findings for insects based on published upper and lower lethal temperature data. The upper thermal limits show little geographical variation. In contrast, the lower bounds of supercooling points and lower lethal temperatures do indeed decline with latitude. However, this is not the case for the upper bounds, leading to an increase in the variation in lower lethal limits with latitude. These results provide some support for the physiological tolerance assumption associated with Rapoport's rule, but highlight the need for coupled data on species tolerances and range size.
Abstract.
Rodrigues AS, Gaston KJ, Gregory RD (2000). Using presence-absence data to establish reserve selection procedures that are robust to temporal species turnover.
Proc Biol Sci,
267(1446), 897-902.
Abstract:
Using presence-absence data to establish reserve selection procedures that are robust to temporal species turnover.
Previous studies suggest that a network of nature reserves with maximum efficiency (obtained by selecting the minimum area such that each species is represented once) is likely to be insufficient to maintain species in the network over time. Here, we test the performance of three selection strategies which require presence-absence data, two of them previously proposed (multiple representations and selecting an increasing percentage of each species' range) and a novel one based on selecting the site where each species has exhibited a higher permanence rate in the past. Multiple representations appear to be a safer strategy than selecting a percentage of range because the former gives priority to rarer species while the latter favours the most widespread. The most effective strategy was the one based on the permanence rate, indicating that the robustness of reserve networks can be improved by adopting reserve selection procedures that integrate information about the relative value of sites. This strategy was also very efficient, suggesting that the investment made in the monitoring schemes may be compensated for by a lower cost in reserve acquisition.
Abstract.
Author URL.
James A, Gaston KJ, Balmford A (2000). Why private institutions alone will not do enough to protect biodiversity [1]. Nature, 404(6774).
Gaston KJ, Blackburn TM (1999). A critique for macroecology.
Oikos,
84(3), 353-368.
Abstract:
A critique for macroecology
The numbers of published macroecological studies are increasing dramatically. Yet, progress within the field of macroecology, and a wider acceptance of its goals and rationale, do not seem to be developing at an equivalent rate. In this paper we examine the criticisms which have been, and can be, made. Attention is drawn to those which withstand scrutiny and are therefore of concern, and some solutions are proffered. We attempt to dispel those criticisms which are misplaced or ill-considered. We conclude that macroecology is likely to progress most effectively in the immediate future, and to make the greatest contribution to the broader study of ecology, if research follows three paths. It needs first to establish a more balanced and better documented body of published patterns, second to establish not simply the presence of patterns but also how in an 'anatomical' sense they come about, and third to expand the program of tests of multiple hypotheses that have been generated to explain observed patterns.
Abstract.
Williamson M, Gaston KJ (1999). A simple transformation for sets of range sizes.
Ecography,
22(6), 674-680.
Abstract:
A simple transformation for sets of range sizes
Transformation of data to normality may be illuminating and useful statistically. There are two standard families of transformations, power transformations for positive numbers, bounded at the left, and folded transformations for proportions, bounded both at the left and the right. It has been shown that there is no one satisfactory power transformation for range size data. However, such measures are limited to the right as well as the left, and we consider applying folded transformations to them. Seven data sets of range sizes recorded by 10 km squares are studied. Six are British (native and introduced plants, mammals, dragonflies and two breeding bird surveys) the seventh is of Swiss breeding birds. Using these we show that the right hand limit of the distribution can be estimated and the best folded transformation found. In all cases the right hand limit is larger than the range size of the most widespread species and smaller than the notional scope of the survey. In all cases the logit or flog, the logarithmic folded transformation, is satisfactory; in five cases it is the best. It is well known that abundance is approximately (though not exactly) log-normally distributed. The relationship of that to our discovery that range size data are approximately logit-normal is discussed. There is no fully satisfactory explanation for either observation at present.
Abstract.
Spicer JI, Gaston KJ, Peck L, Chapelle G (1999). Amphipod gigantism dictated by oxygen availability?.
Ecology Letters,
2(6), 397-403.
Abstract:
Amphipod gigantism dictated by oxygen availability?
A recent study of gigantism in amphipods proposes a novel mechanism which could be used to explain Bergmann's rule, namely differences in environmental O2 concentration. Consideration of the respiratory biology of this group indicates significant flaws in this proposal. Nonetheless, it is not unreasonable to predict a relationship between ectotherm body size and O2 partial pressure (pO2) in some systems, where the partial pressure gradient is steep, either in time (comparison of Carboniferous and Permian atmospheres) or space (animals inhabiting oceanic O2 minimum layers, and, particularly in freshwaters, living at high altitude). Animal gigantism can be correlated with periods of very high environmental pO2 over geological time. Unfortunately, data for present day spatial patterns are scant.
Abstract.
Weeks PJD, O'Neill MA, Gaston KJ, Gauld ID (1999). Automating insect identification: Exploring the limitations of a prototype system.
Journal of Applied Entomology,
123(1), 1-8.
Abstract:
Automating insect identification: Exploring the limitations of a prototype system
Automated identification systems based on computer image analysis technology provide an attractive, but as yet unexploited potential solution to the growing burden of routine species identifications presently faced by a dwindling community of expert taxonomists. DAISY (the Digital Automated Identification SYstem) is a prototype novel automated identification system, developed to explore this possibility. In its pilot phase, the DAISY algorithms were developed to discriminate five species of parasitic wasp, based on differences in their wing structure. Here, again using wing form, the ability of DAISY to discriminate amongst an order of magnitude more species - 49 species of closely related biting midges is examined. In so doing an attempt is made to establish a set of basic 'benchmark' tests of the efficacy, and weaknesses, of such an automated identification system.
Abstract.
James AN, Gaston KJ, Balmford A (1999). Balancing the Earth's accounts.
NATURE,
401(6751), 323-324.
Author URL.
Blackburn TM, Gaston KJ (1999). Density, survey area, and the perfection (or otherwise) of ecologists. Oikos, 85(3), 570-573.
Blackburn TM, Gaston KJ, Quinn RM, Gregory RD (1999). Do local abundances of British birds change with proximity to range edge?.
Journal of Biogeography,
26(3), 493-505.
Abstract:
Do local abundances of British birds change with proximity to range edge?
Aim: Species generally vary in the density they attain at different sites, prompting the question of whether this variation is systematic across their range. We investigate this question using data on the abundance and distribution of thirty-two species of passerine birds across Britain derived from censuses organized by the British Trust for Ornithology. Methods: Analysis is complicated by the issue of quantifying the distance of any particular census location from the edge of the range of a species when the study area encompasses only part of its entire distribution. No measure of this quantity is a priori the correct one, and so we use a variety of different measures which make differing assumptions about how abundances might be structured across species ranges. Results: None of the measures used reveal any consistent relationships between the density attained by species at census sites and the spatial positions of those sites. Only thirteen species show significant relationships with any of the measures, and no more than seven species with any single measure. Main conclusion: in summary, there is no convincing evidence that passerine bird densities are usually lower towards range edges in Britain. We discuss possible reasons for these findings.
Abstract.
Gaston KJ, Blackburn TM, Gregory RD (1999). Does variation in census area confound density comparisons?.
Journal of Applied Ecology,
36(2), 191-204.
Abstract:
Does variation in census area confound density comparisons?
1. Estimates of density are not always independent of the area over which populations are censused. Instead, lower densities tend to be recorded for species when they are censused over larger areas. This may have serious implications for both intra- and interspecific comparisons of density, with relevance to such issues as conservation prioritization and management strategies, because differences in density may simply result from differences in census areas. 2. Here, we use long-term population census data for British birds in the period 196891, drawn from the Common Birds Census (CBC), to examine relationships between density and census area within species, and the consequences of these relationships for intraspecific and interspecific density comparisons. 3. Most British bird species exhibit statistically significant negative relationships between density and census area. We used these relationships to standardize mean density estimates for all species to a common census area. These area-adjusted estimates were usually very similar to geometric mean density estimates calculated without reference to census area. 4. For a subset of species recorded from a large number (> 30) of census sites in each year in the period 1968-91, we used intraspecific density-area relationships for each year to standardize mean density estimates to a common census area in all years. Again, the area-adjusted estimates for each year were usually very similar to the simple geometric mean density estimates calculated for the species in the same year. 5. These results are encouraging, but are certainly a consequence of the relatively limited range of census areas used here, and the fact that the mean census area varies little across species, or across years within species. Moreover, those species occupying few sites are the most likely to have area-biased densities, but are the species for which area-correction will be most difficult. 6. Overall, the results suggest that past analyses conducted using the CBC data are unlikely to have been seriously confounded by variation in census area. Nevertheless, they do highlight that the effects of census area will require consideration by anyone planning to measure or use densities for comparative purposes either within or among species.
Abstract.
Gaston KJ, Chown SL (1999). Elevation and climatic tolerance: a test using dung beetles.
Oikos,
86(3), 584-590.
Abstract:
Elevation and climatic tolerance: a test using dung beetles
An increase in the altitudinal range of occurrence of species in an assemblage with increasing elevation has been explained as a consequence of individual organisms having to be able to withstand a broader range of climatic conditions at higher elevations, the climatic variability hypothesis Here we show that for scarab dung beetles (26 species) across an elevational transect (approx 2500 m) in southern Africa thermal tolerance range does increase with increasing elevation across individuals and across species. The maximal thermal tolerance range exhibited increases slowly with elevation and the minimum range increases more rapidly. The mechanistic basis of the change appears to be one of rapidly changing critical thermal minimum (CT(min)) with elevation and only small changes in critical thermal maximum (CT(max)). of course, even if the pattern of tolerance of species assumed by the climatic variability hypothesis is correct, an increase in altitudinal range with increasing elevation need not necessarily follow. However, although sampling has been limited, there does appear to be an elevational increase in altitudinal range for this species assemblage.
Abstract.
Chown SL, Gaston KJ (1999). Exploring links between physiology and ecology at macro-scales: the role of respiratory metabolism in insects.
Biological Reviews,
74(1), 87-120.
Abstract:
Exploring links between physiology and ecology at macro-scales: the role of respiratory metabolism in insects
The relationships between macro-ecological patterns and physiological investigations in insects, especially those dealing with respiratory metabolism, are assessed in an attempt to encourage the development of the interaction between macroecology and physiological ecology. First, we demonstrate that although physiological ecology has been explicitly concerned with a number of issues relating to species boundaries, many questions remain unanswered. We argue that there are essentially two ways in which the relationship between physiological tolerances and species range boundaries have been investigated. The correlational approach involves physiological inference, physiological prediction, isocline analyses and climatic matching, and has often been criticized for a lack of rigour, while the experimental approach seeks to examine experimentally the relationships between physiological variables and range edges. Second, we use the recent debate on processes underlying latitudinal patterns in body size to caution against the conflation of patterns and processes operating at intraspecific and interspecific levels, the dangers inherent in invoking single explanatory variables, and an undue focus on adaptationist (e.g. optimization) rather than nonadaptationist explanations or some combination of the two. We show that both positive and negative relationships between body size and latitude have been found at the intraspecific level and suggest that interactions between temperature-induced heterochrony, and the relationship between habitat durational stability, growing season length, and generation time can be used to explain these differences. Similar variation in documented patterns is demonstrated at the interspecific level, and the mechanisms usually proffered to explain such clines (especially the starvation/desiccation-resistance hypothesis) are discussed. Interactions between various environmental factors, such as host-plant quality, and their effects on size clines are also discussed. Third, we argue that respiratory metabolism, as a measure of ATP cost, and its spatio-temporal variation are critical to many explanations of macroecological patterns. Adaptive changes in metabolism reputedly involve both depression (stress resistance) and elevation of metabolic rate, although recent studies are increasingly calling these ideas into question. In particular, flow-through respirometry is revolutionizing results by allowing careful separation of resting (or standard) and active metabolic rates. These techniques have rarely been applied to studies of metabolic cold adaptation in insects, one of the most polemical adaptations ascribed to high-latitude and high-altitude species. We conclude by arguing that physiological investigations of species tolerances are important in the context of macroecology, especially species distributional patterns and the possible impact of climate change thereon. However, we caution that relationships between abiotic variables, species tolerances, and distributional ranges may be non-linear and subject to considerable modification by the presence of other species, and that many of the pressing questions posed by macroecology have not been addressed by insect physiologists. Nonetheless, we suggest that because an understanding of the dynamics of species distributions is of considerable importance, especially in the context of current conservation problems, insect physiological ecology has much future scope. © 1999 Blackwell Publishing Ltd.
Abstract.
Chown SL, Gaston KJ (1999). Exploring links between physiology and ecology at macro-scales: the role of respiratory metabolism in insects.
Biological Reviews of the Cambridge Philosophical Society,
74(1), 87-120.
Abstract:
Exploring links between physiology and ecology at macro-scales: the role of respiratory metabolism in insects
The relationships between macro-ecological patterns and physiological investigations in insects, especially those dealing with respiratory metabolism, are assessed in an attempt to encourage the development of the interaction between macroecology and physiological ecology. First, we demonstrate that although physiological ecology has been explicitly concerned with a number of issues relating to species boundaries, many questions remain unanswered. We argue that there are essentially two ways in which the relationship between physiological tolerances and species range boundaries have been investigated. The correlational approach involves physiological inference, physiological prediction, isocline analyses and climatic matching, and has often been criticized for a lack of rigour, while the experimental approach seeks to examine experimentally the relationships between physiological variables and range edges. Second, we use the recent debate on processes underlying latitudinal patterns in body size to caution against the conflation of patterns and processes operating at intraspecific and interspecific levels, the dangers inherent in invoking single explanatory variables, and an undue fetus on adaptationist (e.g. optimization) rather than non-adaptationist explanations or some combination of the two. We show that both positive and negative relationships between body size and latitude have been found at the intraspecific level and suggest that interactions between temperature-induced heterochrony, and the relationship between habitat durational stability, growing season length, and generation time can be used to explain these differences. Similar variation in documented patterns is demonstrated at the interspecific level, and the mechanisms usually proffered to explain such clines (especially the starvation/desiccation-resistance hypothesis) are discussed. Interactions between various environmental factors, such as host-plant quality, and their effects on size clines are also discussed. Third, we argue that respiratory metabolism, as a measure of ATP cost, and its spatio-temporal variation are critical to many explanations of macroecological patterns. Adaptive changes in metabolism reputedly involve both depression (stress resistance) and elevation of metabolic rate, although recent studies are increasingly calling these ideas into question. In particular, flow-through respirometry is revolutionizing results by allowing careful separation of resting (or standard) and active metabolic rates. These techniques have rarely been applied to studies of metabolic cold adaptation in insects, one of the most polemical adaptations ascribed to high-latitude and high-altitude species. We conclude by arguing that physiological investigations of species tolerances are important in the contest of macroecology, especially species distributional patterns and the possible impact of climate change thereon. However, we caution that relationships between abiotic variables, species tolerances, and distributional ranges may be non-linear and subject to considerable modification by the presence of other species, and that many of the pressing questions posed by macroecology have not been addressed by insect physiologists. Nonetheless, we suggest that because an understanding of the dynamics of species distributions is of considerable importance, especially in the context of current conservation problems, insect physiological ecology has much future scope.
Abstract.
Blackburn TM, Gaston KJ, Loder N (1999). Geographic gradients in body size: a clarification of Bergmann's rule.
Diversity and Distributions,
5(4), 165-174.
Abstract:
Geographic gradients in body size: a clarification of Bergmann's rule
1997 marked the sesquicentenary of the publication by Carl Bergmann of the observation that, in general, large-bodied animal species tend to live further north than their small-bodied relatives. This has been dubbed Bergmann's rule in his honour. However, more than 150 years on, we appear to be little closer to a general understanding of the rule, or even to any consensus as to whether it exists. This is due in large part to confusion about the taxonomic level at which the rule is considered to operate, and to the conflation of pattern and mechanism. In this paper, we attempt to resolve this confusion by highlighting its sources, and by providing a definition of Bergmann's rule that is practical and useful, yet that retains the essential features of its original formulation. We conclude by briefly reviewing the mechanisms proposed to explain Bergmann's rule as we define it.
Abstract.
Gaston KJ (1999). Implications of interspecific and intraspecific abundance-occupancy relationships.
Oikos,
86(2), 195-207.
Abstract:
Implications of interspecific and intraspecific abundance-occupancy relationships
Positive interspecific and intraspecific relationships between local abundance and regional occupancy have been widely documented. The former are essentially pervasive. These patterns have some potentially significant applied implications: (1) Biodiversity inventorying - there can be no simple and effective trade-off between the intensity and spatial extent of biodiversity inventorying, (2) Population monitoring - intraspecific, and to a more limited extent interspecific, population monitoring may be based on measures of occupancy, particularly where only crude indications of marked shifts in abundance are required, (3) Harvesting - harvesting of local populations may often result in a reduction in wider occupancy, but if local extinctions are caused by over-exploitation this may not generally result in a reduction in local abundance elsewhere in the range of a species, (4) Conservation species of conservation concern may face the double jeopardy of low abundance and small range size, but depending on the extent of a causal link between levels of abundance and occupancy it may be possible to cheat the abundance-occupancy relationship and maintain species at relatively high local densities for their range sizes, and (5) Invasions - pest species may become more of a problem in those areas in which they already occur, because their local densities will increase, as they spread.
Abstract.
Gaston KJ, Blackburn TM, Gregory RD (1999). Intraspecific abundance-occupancy relationships: Case studies of six bird species in Britain.
Diversity and Distributions,
5(5), 197-212.
Abstract:
Intraspecific abundance-occupancy relationships: Case studies of six bird species in Britain
Although acknowledged to be common, intraspecific relationships between local abundance and site occupancy have been examined in detail for few species. Here we report such analyses for six widespread species of breeding birds in Britain, using data from the Common Birds Census. These exhibit a range of temporal trends, including different combinations of increase and decrease in abundance and occupancy. Overall, two species have a statistically significant positive abundance-occupancy relationship on farmland but no relationship in woodland (collared dove, tree sparrow), one a significant positive relationship on farmland and in woodland (magpie), two a significant positive relationship on farmland and a negative one in woodland (redstart, song thrush), and one a significant negative abundance-occupancy relationship on farmland but no relationship in woodland (sparrowhawk). The population dynamics associated with these patterns are used to discern their underlying mechanisms.
Abstract.
Gaston KJ, Gregory RD, Blackburn TM (1999). Intraspecific relationships between abundance and occupancy among species of Paridae and Sylviidae in Britain.
Ecoscience,
6(2), 131-142.
Abstract:
Intraspecific relationships between abundance and occupancy among species of Paridae and Sylviidae in Britain
Relationships between local abundance and occupancy of two groups of three bird species from the families Paridae and Sylviidae were examined using data from the Common Birds Census over the period 1968-1991. Temporal trends in local abundance and occupancy are described and their covariation assessed on a species-by-species basis in both farmland and woodland habitats. For the most part, members of the Paridae have increased in abundance and occupancy over this period while members of the Sylviidae show a range of population trajectories. These associations are translated into positive intraspecific abundance-occupancy relationships for all species on farmland, but for none in woodland. We speculate that the failure to establish abundance-occupancy correlations in woodland is due to greater variance in measures of local abundance (and occupancy) within this habitat. Biological and non-biological explanations for this variance are discussed.
Abstract.
Chown SL, Gaston KJ (1999). Patterns in procellariiform diversity as a test of species-energy theory in marine systems.
Evolutionary Ecology Research,
1(3), 365-373.
Abstract:
Patterns in procellariiform diversity as a test of species-energy theory in marine systems
Biological diversity varies systematically in space with levels of primary productivity. Within regions, the relationship is hump-shaped, but across larger areas it tends to be monotonic and positive. However, the generality of this latter pattern, particularly within marine systems, is not clear. Here a global analysis across regions shows that the relationship between species richness of Procellariiformes (albatrosses, petrels, storm-petrels, diving-petrels) and remotely sensed chlorophyll concentrations, a surrogate for primary productivity, is hump-shaped with a single mode. The decline in richness at higher productivities is associated with an increase in the temporal variability in levels of productivity and a decline in the areal extent of these productivities. It appears that the relationship between the areal extent of productivity classes and species richness is, in part, a function of a positive relationship between local (grid cell) and regional (productivity class) procellariiform species richness. We argue that the relationship between the temporal mean and variance in levels of productivity may be of general importance in explaining differences in the response of species to increasing productivity. Wherever the relationship between productivity and its variance is negative, a positive monotonic species richness response may be expected, whereas a unimodal response may be expected where the productivity mean-variance relationship is positive. In the southern oceans, the relationship between productivity and species richness results in coincidence between areas of high procellariiform species richness and high resource harvesting by humans, to the detriment of the birds.
Abstract.
Thompson K, Gaston KJ, Band SR (1999). Range size, dispersal and niche breadth in the herbaceous flora of central England.
JOURNAL OF ECOLOGY,
87(1), 150-155.
Author URL.
Erasmus BFN, Freitag S, Gaston KJ, Erasmus BH, Van Jaarsveld AS (1999). Scale and conservation planning in the real world.
Proceedings of the Royal Society B: Biological Sciences,
266(1417), 315-319.
Abstract:
Scale and conservation planning in the real world
Conservation planning is carried out on a variety of geopolitical and biogeographical scales. Whereas considerable consensus is emerging about the most appropriate procedures for identifying conservation areas, the spatial implications of conducting conservation planning at divergent scales have received little attention. Here we explore the consequences of planning at different geopolitical scales, using a database of the mammalian fauna from the Northern Provinces of South Africa. The conservation network resulting from treating the region as one unit is compared with networks generated separately for the provinces nested in that region. These outcomes are evaluated in terms of (i) their land use efficiencies, (ii) their spatial overlap, and (iii) the impact of algorithm attributes. Although land efficiencies are greater on broader scales, on average the spatial congruence between the broad-scale regional network and fine-scale provincial networks was < 14%. Algorithms using different selection rules fail to improve this disturbing outcome. Consequently, scale has an overwhelming influence on areas identified as conservation networks in geopolitical units. This should be recognized in conservation planning.
Abstract.
Weeks PJD, O'Neill MA, Gaston KJ, Gauld ID (1999). Species-identification of wasps using principal component associative memories.
Image and Vision Computing,
17(12), 861-866.
Abstract:
Species-identification of wasps using principal component associative memories
This paper presents a novel approach to image-based insect specimen identification, exploiting the ability of principal component auto associative memories to form trainable classifiers, which may be used to identify unknown images. The system utilizes the differences between a pair of reconstructed images produced when the unknown image is included in, and then excluded from the training set encoded by the auto associative memory. A non-parametric statistical correlation metric, Kendall's t, was used to correlate the reconstructed images. The approach has been applied to the species-identification of closely related parasitic wasps based upon their wing venation and pigmentation patterns.
Abstract.
Rodrigues ASL, Tratt R, Wheeler BD, Gaston KJ (1999). The performance of existing networks of conservation areas in representing biodiversity.
Proceedings of the Royal Society B: Biological Sciences,
266(1427), 1453-1460.
Abstract:
The performance of existing networks of conservation areas in representing biodiversity
It is widely held that existing reserve systems are inadequate in representing the diversity of biological features of the regions in which they reside. Evidence for this argument has, however, derived principally from analyses of the efficiency of networks when compared with a minimum set that represents each species at least once. Here, we examine the efficiency of the system of Sites of Special Scientific Interest (SSSIs) in representing wetland plants in fen sites in the Scottish Borders, a region where reserve networks might be expected a priori to perform reasonably well in this regard. The results support the general contention that networks have been designated in an inefficient manner. However, examined in terms of effectiveness (measured as the gap between the representation target required and the one attained by the existing network), the SSSI system is actually a rather good way of representing diversity. This result is consistent when each of several very different representation targets is evaluated, and suggests that a more balanced approach to evaluating the performance of reserve networks should be employed, and that general statements based on existing analyses should be treated cautiously.
Abstract.
Blackburn TM, Gaston KJ (1999). The relationship between animal abundance and body size: a review of the mechanisms.
ADVANCES IN ECOLOGICAL RESEARCH, VOL 28,
28, 181-210.
Author URL.
Gaston KJ, Chown SL (1999). Why Rapoport's rule does not generalise. Oikos, 84(2), 309-312.
Balmford A, Gaston KJ (1999). Why biodiversity surveys are good value. Nature, 398(6724), 204-205.
Thompson K, Hodgson JG, Gaston KJ (1998). Abundance-range size relationships in the herbaceous flora of central England.
Journal of Ecology,
86(3), 439-448.
Abstract:
Abundance-range size relationships in the herbaceous flora of central England
1. Using data from a survey of over 10 000 1-m2 quadrats in a 3000-kin2 area, we examined the relationship between abundance and range for the vascular plant flora of central England. 2. At the level of the whole landscape, abundance was not related to local, regional or national range. Local, regional and national range were closely related to each other. 3. At the level of the whole landscape, range was significantly and positively related to both niche breadth (expressed as the range of habitats exploited) and to habitat availability, although niche breadth appeared to be more important. Abundance was not related to niche breadth or habitat availability. Since specialist species are mainly confined to uncommon habitats (especially wetlands), we conclude that the relationship between range and niche breadth is not an artefact of widespread species passively sampling more habitats. 4. At the level of individual habitat types, significant positive relationships between range and abundance were common. These relationships remained after controlling for the effects of phylogeny. For predominantly annual weed communities, the relationship was linear, but for perennial communities it was markedly 'upper triangular', i.e. all combinations of range and abundance were found except wide range/low abundance. The evidence suggests that this difference can be attributed to the greater mobility of annual weeds.
Abstract.
Gaston KJ, Blackburn TM, Lawton JH (1998). Aggregation and interspecific abundance-occupancy relationships. Journal of Animal Ecology, 67(6), 995-999.
Gaston KJ (1998). Biodiversity - the road to an atlas. Progress in Physical Geography, 22(2), 269-281.
Williams PH, Gaston KJ (1998). Biodiversity indicators: Graphical techniques, smoothing and searching for what makes relationships work.
Ecography,
21(5), 551-560.
Abstract:
Biodiversity indicators: Graphical techniques, smoothing and searching for what makes relationships work
Knowledge of the distribution of biodiversity remains poor. This situation might more readily be resolved if the species richness of certain groups of organisms indicated the richness of other, less well known groups. A spatially explicit exploration of the pattern in the predictive power that one taxon (a potential 'indicator group') might have for the diversity of another has been performed previously. In this paper we respond to three important points that have been raised. First, we describe an additional graphical technique for visualising spatial aspects of indicator relationships. Second, we examine some of the consequences of smoothing species richness data on observed indicator relationships. Third, we consider some of the factors that may contribute to strong indicator relationships.
Abstract.
Loder N, Gaston KJ, Warren PH, Arnold HR (1998). Body size and feeding specificity: Macrolepidoptera in Britain.
Biological Journal of the Linnean Society,
63(1), 121-139.
Abstract:
Body size and feeding specificity: Macrolepidoptera in Britain
Within a geographic assemblage, large-bodied species of macrolepidopteran moths tend, on average, to be less host-specific than small-bodies. Five possible explanations for this pattern are identified, based respectively on (i) phylogenetic relationships between species, (ii) latitudinal gradients in body size and feeding specificity, (iii) the relationship between range size and body size, (iv) larger body size as a buffer from environmental variation, and (v) the relationship between endophagous host associations and small body size. These mechanisms are tested using data for British macrolepidoptera and also evaluated using evidence from the literature at large. Although some of their assumptions are found to be justified, there is no significant support for any single mechanism. This lack of evidence for previously proposed mechanisms is discussed in the light of a recently proposed alternative explanation which combines theories of host quality and host defence mechanisms.
Abstract.
Quinn RM, Gaston KJ, Roy DB (1998). Coincidence in the distributions of butterflies and their foodplants.
Ecography,
21(3), 279-288.
Abstract:
Coincidence in the distributions of butterflies and their foodplants
The relationship between the geographic distribution of consumers and of their hosts (foodplants) is examined using the resident butterfly fauna of Britain. On average, butterfly species that feed on more widely distributed hosts are themselves more widely distributed. However, the relationship is approximately triangular and the upper constraint imposed by the range sizes of hosts is not closely followed; some species have much more restricted ranges than their hosts have. There is no relationship between the proportion of the range of' the foodplant that is occupied and the size of the range of the foodplant. Monophagous butterfly species have smaller range sizes than polyphagous species, probably as a consequence of the greater potential range sizes of the latter. Those plant species that are used as hosts by butterflies have larger range sizes than expected by chance, and individual polyphagous butterfly species tend disproportionately to be found in areas containing larger numbers of their host plant species. In sum, this study reveals a complex relationship between the distribution of butterflies and that of their resources (foodplants).
Abstract.
Gaston KJ, Spicer JI (1998). Do upper thermal tolerances differ in geographically separated populations of the beachflea Orchestia gammarellus (Crustacea: Amphipoda)?.
Journal of Experimental Marine Biology and Ecology,
229(2), 265-276.
Abstract:
Do upper thermal tolerances differ in geographically separated populations of the beachflea Orchestia gammarellus (Crustacea: Amphipoda)?
Fundamental (as opposed to realised) between-population differences in maximum temperature tolerances were examined for the common beachflea of European shores, Orchestia gammarellus. Individuals were collected from two distinct populations, one in S.E. England and one in N. Scotland, and were acclimated to a number of different thermal regimes (5, 10, 15, 20 and 25°C). Temperature tolerances increased with body size for virtually all combinations of population and acclimation temperature tested. Such a relationship complicates comparison between populations, although when body size differences were controlled for at two acclimation temperatures, individuals of the southern population tended to have higher thermal tolerances. Controlling for body size tends, however, to underestimate the difference in temperature tolerances of the two populations. This is because the southern population consist