Showing papers by "Andy Purvis published in 2017"

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

Abstract: The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Multiscale scenarios for nature futures

Abstract: Targets for human development are increasingly connected with targets for nature, however, existing scenarios do not explicitly address this relationship. Here, we outline a strategy to generate scenarios centred on our relationship with nature to inform decision-making at multiple scales.

Land-use effects on local biodiversity in tropical forests vary between continents

Abstract: Land-use change is one of the greatest threats to biodiversity, especially in the tropics where secondary and plantation forests are expanding while primary forest is declining. Understanding how well these disturbed habitats maintain biodiversity is therefore important-specifically how the maturity of secondary forest and the management intensity of plantation forest affect levels of biodiversity. Previous studies have shown that the biotas of different continents respond differently to land use. Any continental differences in the response could be due to differences in land-use intensity and maturity of secondary vegetation or to differences among species in their sensitivity to disturbances. We tested these hypotheses using an extensive dataset collated from published biodiversity comparisons within four tropical regions-Asia, Africa, Central America and South America-and a wide range of animal and plant taxa. We analysed responses to land use of several aspects of biodiversity-species richness, species composition and endemicity-allowing a more detailed comparison than in previous syntheses. Within each continent, assemblages from secondary vegetation of all successional stages retained species richness comparable to those in primary vegetation, but community composition was distinct, especially in younger secondary vegetation. Plantation forests, particularly the most intensively managed, supported a smaller-and very distinct-set of species from sites in primary vegetation. Responses to land use did vary significantly among continents, with the biggest difference in richness between plantation and primary forests in Asia. Responses of individual taxonomic groups did not differ strongly among continents, giving little indication that species were inherently more sensitive in Asia than elsewhere. We show that oil palm plantations support particularly low species richness, indicating that continental differences in the response of biodiversity to land use are perhaps more likely explained by Asia's high prevalence of oil palm plantations.

Dimensions of biodiversity loss: Spatial mismatch in land-use impacts on species, functional and phylogenetic diversity of European bees.

Abstract: Aim Agricultural intensification and urbanization are important drivers of biodiversity change in Europe. Different aspects of bee community diversity vary in their sensitivity to these pressures, as well as independently influencing ecosystem service provision (pollination). To obtain a more comprehensive understanding of human impacts on bee diversity across Europe, we assess multiple, complementary indices of diversity. Location One Thousand four hundred and forty six sites across Europe. Methods We collated data on bee occurrence and abundance from the published literature and supplemented them with the PREDICTS database. Using Rao's Quadratic Entropy, we assessed how species, functional and phylogenetic diversity of 1,446 bee communities respond to land-use characteristics including land-use class, cropland intensity, human population density and distance to roads. We combined these models with statistically downscaled estimates of land use in 2005 to estimate and map—at a scale of approximately 1 km2—the losses in diversity relative to semi-natural/natural baseline (the predicted diversity of an uninhabited grid square, consisting only of semi-natural/natural vegetation). Results We show that—relative to the predicted local diversity in uninhabited semi-natural/natural habitat—half of all EU27 countries have lost over 10% of their average local species diversity and two-thirds of countries have lost over 5% of their average local functional and phylogenetic diversity. All diversity measures were generally lower in pasture and higher-intensity cropland than in semi-natural/natural vegetation, but facets of diversity showed less consistent responses to human population density. These differences have led to marked spatial mismatches in losses: losses in phylogenetic diversity were in some areas almost 20 percentage points (pp.) more severe than losses in species diversity, but in other areas losses were almost 40 pp. less severe. Main conclusions These results highlight the importance of exploring multiple measures of diversity when prioritizing and evaluating conservation actions, as species-diverse assemblages may be phylogenetically and functionally impoverished, potentially threatening pollination service provision.

Local factors mediate the response of biodiversity to land use on two African mountains

Abstract: Land-use change is the single biggest driver of biodiversity loss in the tropics. Biodiversity models can be useful tools to inform policymakers and conservationists of the likely response of species to anthropogenic pressures, including land-use change. However, such models generalize biodiversity responses across wide areas and many taxa, potentially missing important characteristics of particular sites or clades. Comparisons of biodiversity models with independently collected field data can help us understand the local factors that mediate broad-scale responses. We collected independent bird occurrence and abundance data along two elevational transects in Mount Kilimanjaro, Tanzania and the Taita Hills, Kenya. We estimated the local response to land use and compared our estimates with modelled local responses based on a large database of many different taxa across Africa. To identify the local factors mediating responses to land use, we compared environmental and species assemblage information between sites in the independent and African-wide datasets. Bird species richness and abundance responses to land use in the independent data followed similar trends as suggested by the African-wide biodiversity model, however the land-use classification was too coarse to capture fully the variability introduced by local agricultural management practices. A comparison of assemblage characteristics showed that the sites on Kilimanjaro and the Taita Hills had higher proportions of forest specialists in croplands compared to the Africa-wide average. Local human population density, forest cover and vegetation greenness also differed significantly between the independent and Africa-wide datasets. Biodiversity models including those variables performed better, particularly in croplands, but still could not accurately predict the magnitude of local species responses to most land uses, probably because local features of the land management are still missed. Overall, our study demonstrates that local factors mediate biodiversity responses to land use and cautions against applying biodiversity models to local contexts without prior knowledge of which factors are locally relevant.

Biodiversidad 2016. Estado y Tendencias de la Biodiversidad Continental de Colombia

Abstract: Esta tercera entrega del reporte anual de la biodiversidad en Colombia profundiza en la linea editorial iniciada el ano 2014 mediante nuevas propuestas analiticas y graficas, con la intencion de garantizar que la informacion llegue a todos los publicos y pueda ser discutida de manera amena sin sacrificio de calidad. La apuesta comunicativa sigue siendo central en el proyecto institucional y los nuevos lenguajes con los que estamos aprendiendo a conversar con la sociedad y las instituciones son un experimento que esperamos sea cada vez mas satisfactorio: ya estamos construyendo la version 2017 con el apoyo de las nuevas tecnologias digitales de manera que la potencia de la conexion vital colombiana se exprese en toda su capacidad. Por los contenidos es evidente que aun distamos mucho de tener una capacidad de seguimiento sistematico para la mayoria de temas relativos a la gestion de la biodiversidad y los servicios ecosistemicos, la unica manera de evaluar si las medidas de politica y las inversiones que realiza la sociedad estan teniendo los efectos deseados. De hecho, parte de las limitaciones reconocidas por robustamente los cambios positivos o negativos que afectan los diferentes niveles de organizacion de la vida planetaria, por lo cual las mismas metas de Aichi, nuestra carta de navegacion global, estan pendientes de verificacion. Un proposito adicional de este proceso es la invitacion a todos los colombianos para contribuir con la construccion y alimentacion de los indicadores basicos de seguimiento a la gestion, ya que es imposible identificar las tendencias de largo plazo en que estan inmersas la flora y fauna colombianas sin el apoyo de las instituciones, los investigadores y los ciudadanos: en el pais de la megadiversidad, el reto es inmenso. Por este motivo, este reporte ira abriendo sus paginas a expertos, incluso indigenas o de comunidades locales, para que presenten de manera sistematica y documentada sus perspectivas del cambio ambiental y sus efectos en la biodiversidad, con el animo de promover el compromiso de todos en su gestion. La unica manera de superar el riesgo de extincion es mediante un activo proceso de aprendizajes sociales que haga que todos los sectores asuman una parte de la compleja responsabilidad que significa proteger todas las formas de vida del pais, una decima parte mal contada de las planetarias. Agradezco a las decenas de personas que contribuyeron con este reporte, a quienes nos han apoyado en todas las etapas de produccion y a sus lectores y usuarios, quienes son en ultimo termino los jueces de su utilidad.

Estimating the potential biodiversity impact of redeveloping small urban spaces: the Natural History Museum's grounds.

Abstract: Background With the increase in human population, and the growing realisation of the importance of urban biodiversity for human wellbeing, the ability to predict biodiversity loss or gain as a result of land use change within urban settings is important. Most models that link biodiversity and land use are at too coarse a scale for informing decisions, especially those related to planning applications. Using the grounds of the Natural History Museum, London, we show how methods used in global models can be applied to smaller spatial scales to inform urban planning. Methods Data were extracted from relevant primary literature where species richness had been recorded in more than one habitat type within an urban setting. As within-sample species richness will increase with habitat area, species richness estimates were also converted to species density using theory based on the species-area relationship. Mixed-effects models were used to model the impact on species richness and species density of different habitat types, and to estimate these metrics in the current grounds and under proposed plans for redevelopment. We compared effects of three assumptions on how within-sample diversity scales with habitat area as a sensitivity analysis. A pre-existing database recording plants within the grounds was also used to estimate changes in species composition across different habitats. Results Analysis estimated that the proposed plans would result in an increase of average biodiversity of between 11.2% (when species density was modelled) and 14.1% (when within-sample species richness was modelled). Plant community composition was relatively similar between the habitats currently within the grounds. Discussion The proposed plans for change in the NHM grounds are estimated to result in a net gain in average biodiversity, through increased number and extent of high-diversity habitats. In future, our method could be improved by incorporating purposefully collected ecological survey data (if resources permit) and by expanding the data sufficiently to allow modelling of the temporal dynamics of biodiversity change after habitat disturbance and creation. Even in its current form, the method produces transparent quantitative estimates, grounded in ecological data and theory, which can be used to inform relatively small scale planning decisions.

Trait correlates of climatic niche tracking in British birds

Abstract: Growing evidence indicates that species respond idiosyncratically when exposed to the same changes in climate. As a result, understanding the potential influence of biological traits on species9 distributional responses is a research priority. Yet, empirical support for hypothesised influences of traits on climate change responses remains equivocal. In this paper, we developed a novel approach to determine whether biological traits predict the degree of climatic niche tracking of British breeding birds in response to recent climate change. First, we quantified how well predicted positive and negative changes in probability of presence from climate-based species distribution models agreed with observed local gains and losses in species9 occupancy - our measure of climatic niche tracking. Second, we examined whether the degree of climatic niche tracking could be predicted by species9 ecological and life-history traits, as well as phylogenetic relationships. Overall, British breeding birds displayed a low degree of climatic niche tracking over the period of our study, though this varied substantially among species. Models incorporating traits and phylogeny explained a low proportion of the variation in climatic niche tracking. Nevertheless, we did find statistical evidence that species with lower lifespans tracked their climatic niches more closely, whilst species with a mixed diet displayed a lower degree of climatic niche tracking. We present here a tractable approach for quantifying the degree to which observed local range gains and losses can be related to climate redistribution and apply it to British breeding birds. Although we do not find strong evidence that traits predict the degree of climatic niche tracking, we discuss why this is likely to be a consequence of the features of our study system rather than the approach itself. We believe this approach may prove to be useful as datasets of temporal changes in species distributions become increasingly available.