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To investigate the relative contributions of current vs. historical factors in explaining broad-scale diversity gradients using a combination of contemporary factors and a quantitative estimate of the temporal accessibility of areas for recolonization created by glacial retreat following the most recent Ice Age. The part of the Nearctic region of North America that was covered by ice sheets during the glacial maximum 20 000 BP. We used range maps to estimate the species richness of mammals and terrestrial birds in 48 400 km2 cells. Current conditions in each cell were quantified using seven climatic and topographical variables. Historical conditions were estimated using the number of years before present when an area became exposed as the ice sheets retreated during the post-Pleistocene climate warming. We attempted to tease apart contemporary and historical effects using multiple regression, partial regression and spatial autocorrelation analysis. A measure of current energy inputs, potential evapotranspiration, explained 76–82% of the variance in species richness, but time since deglaciation explained an additional 8–13% of the variance, primarily due to effects operating at large spatial scales. Because of spatial covariation between the historical climates influencing the melting of the ice sheet and current climates, it was not possible to partition their effects fully, but of the independent effects that could be identified, current climate explained two to seven times more variance in richness patterns than age. Factors acting in the present appear to have the strongest influence on the diversity gradient, but an historical signal persisting at least 13 000 years is still detectable. This has implications for modelling changes in diversity patterns in response to future global warming. [ABSTRACT FROM AUTHOR]

Aim Little is known about how marine biodiversity responds to oceanographic and climatic changes over the decadal to centennial time-scales which are most relevant for predicted climate changes due to greenhouse gas forcing. This paper aims to reveal decadal-centennial scale deep-sea biodiversity dynamics for the last 20,000 years and then explore potential environmental drivers. Location The North Atlantic Ocean. Methods We investigated deep-sea benthic microfossil records to reveal biodiversity dynamics and subsequently applied comprehensive ecological modelling to test possible environmental factors (i.e. surface productivity, seasonality of productivity or deepwater circulation related to bottom-water temperature) that may have influenced deep-sea biodiversity over these time-scales. Results Deep-sea biodiversity changed synchronously with stadial-interstadial climate changes over the last 20,000 years across a large area of the North Atlantic in both ostracod crustaceans and foraminiferan protozoa (in spite of their different dispersal abilities). Species diversity rapidly increased during abrupt stadial events during the last deglacial and the Holocene interglacial periods. These include the well-known Heinrich 1, the Younger Dryas and the 8.2 ka events when the strength of Atlantic Meridional Overturning Circulation ( AMOC) decreased. There is also evidence for quasi-cyclic changes in biodiversity at a c. 1500-year periodicity, consistent with the well-known '1500-year climatic cycle'. Statistical analyses revealed that AMOC variability (probably specifically the variability in AMOC-driven bottom-water temperature) is correlated with deep-sea biodiversity. Main conclusions Our finding of a significant AMOC-diversity relationship may indicate pervasive control of the diversity of deep-sea benthic species by rapidly changing climate, specifically bottom-water temperature, over decadal to centennial time-scales. Our results, based on highly resolved fossil records, may portend pervasive, synchronous and sudden ecosystem responses to human-induced changes to climate and ocean circulation in this century. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim This paper describes a set of integrative scenarios developed in the ALARM (Assessing LArge-scale environmental Risks for biodiversity with tested Methods) project. The ultimate aim of ALARM was to develop and test methods and protocols for the assessment of large-scale environmental risks to biodiversity and to evaluate mitigation options. Scenarios provide a tool for exploring such risks and the policy options to mitigate them; therefore they play a central role within the ALARM project. Methods Three integrative scenarios (liberalization, business as might be usual, sustainability) were developed and illustrated using the econometric model described in a subsequent paper. They are contextualized with projections from climate models and provide the input for model-based assessments of biodiversity trends. Additionally, three shock scenarios were developed (Gulf Stream collapse, peak oil, pandemic) to demonstrate the limits of linear extrapolation. As these extend beyond model capabilities, they are discussed semi-quantitatively based on modelling insights. Results Although the policy impacts on biodiversity are different for different pressures, biomes and species groups, some general trends could be identified. An extension of current EU policies will act as a brake on current trends by slowing down the loss of biodiversity in many cases and in most biomes, but it will be capable of neither halting nor of reversing the loss. Liberalization has the effect of accelerating biodiversity loss across the board, with few exceptions. A coherent sustainability scenario is clearly the most effective at preserving biodiversity, but the variant tested here still does not halt losses in all cases. Main conclusions Current EU policies for protecting biodiversity appear to be insufficient to reverse ongoing losses. Coherent sustainability strategies are effective at conserving biodiversity, but in order to assess losses and then reverse them, measures would need to be introduced that extend beyond the steps tested in the ALARM sustainability scenario. [ABSTRACT FROM AUTHOR]

Aim Species richness depends on climate and land use. Maintaining locations with favourable climate and land-use patterns is critical for protecting biodiversity because the loss of either can reduce the species richness that an area supports. Currently, the Guiana Shield (GS) receives abundant precipitation and has relatively light land use. For species richness this constitutes a good–good combination of climate and land use, respectively. In contrast, much of eastern Brazil receives low levels of precipitation and has heavy land use, which is a bad–bad combination for species richness. Thus, the current distribution of precipitation and land use in northern South America is relatively favourable for biodiversity. Palaeoclimate and model studies suggest, however, that the precipitation patterns for the two regions have switched before and could switch in response to greenhouse gas emissions. This paper examines the potential consequences of reconfiguring climate with respect to existing land-use patterns using South America as an example. Location South America north of 20° S and east of the Andes. Methods Ecosystem structure and function are modelled under (1) historical climate and (2) altered precipitation following a shift in the location of the Inter-Tropical Convergence Zone (ITCZ). The distribution of precipitation, biomes, net primary productivity (NPP) and land use are then used to predict levels of species richness under the two climate scenarios. Results Climate changes could shift the distribution of vegetation and NPP such that conditions favourable for species richness in the GS region disappear. If land-use patterns were not prohibitive in eastern Brazil, the improved climate conditions there could compensate for the GS loss (assuming migratory barriers are overcome). Instead, existing land-use patterns cause the combined species richness projected for the two regions to plummet. Main conclusions Human activities will alter current configurations of land use and climate throughout the world. For species richness, new configurations are likely to include both positive and negative combinations of climate and land use. However, the irreversibility of past extinctions due to land-use patterns loads the dice against species richness. [ABSTRACT FROM AUTHOR]

Aim: Until recently, complete information on global reptile distributions has not been widely available. Here, we provide the first comprehensive climate impact assessment for reptiles on a global scale. Location: Global, excluding Antarctica. Time period: 1995, 2050 and 2080. Major taxa studied: Reptiles. Methods: We modelled the distribution of 6296 reptile species and assessed potential global and realm‐specific changes in species richness, the change in global species richness across climate space, and species‐specific changes in range extent, overlap and position under future climate change. To assess the future climatic impact on 3768 range‐restricted species, which could not be modelled, we compared the future change in climatic conditions between both modelled and non‐modelled species. Results: Reptile richness was projected to decline significantly over time, globally but also for most zoogeographical realms, with the greatest decreases in Brazil, Australia and South Africa. Species richness was highest in warm and moist regions, with these regions being projected to shift further towards climate extremes in the future. Range extents were projected to decline considerably in the future, with a low overlap between current and future ranges. Shifts in range centroids differed among realms and taxa, with a dominant global poleward shift. Non‐modelled species were significantly stronger affected by projected climatic changes than modelled species. Main conclusions: With ongoing future climate change, reptile richness is likely to decrease significantly across most parts of the world. This effect, in addition to considerable impacts on species range extent, overlap and position, was visible across lizards, snakes and turtles alike. Together with other anthropogenic impacts, such as habitat loss and harvesting of species, this is a cause for concern. Given the historical lack of global reptile distributions, this calls for a re‐assessment of global reptile conservation efforts, with a specific focus on anticipated future climate change. [ABSTRACT FROM AUTHOR]

Aim: The environmental preferences of species are an important facet of their response to changing conditions, and these have long been thought to exhibit phylogenetic conservatism. However, these bioclimatic envelopes have not previously been imputed from climate records at the date and location of occurrence, and the strength of their phylogenetic signal has not been studied at a broad scale. Here, we combine records from global climate reconstructions with contemporaneous plant occurrences for all available terrestrial plant species and test for phylogenetic niche conservatism in plant climatic traits. Location: Global. Time period: 1901–2018. Major taxa studied: Terrestrial plants. Methods: We used >100 million plant records from the Global Biodiversity Information Facility (GBIF) to produce distributions of bioclimatic envelopes for >200,000 species, using a range of climate variables. We matched species observations to historical climate reconstructions from the European Centre for Medium‐Range Weather Forecasting (ECMWF) and compared this with WorldClim climate averages. We tested for phylogenetic signal in a supertree of plants using Pagel's λ. Finally, to investigate how well bioclimatic envelopes could be inferred for poorly known and rare species, we performed cross‐validation by removing occurrence records for some common species to test how accurately their bioclimatic envelopes were estimated. Results: We found extremely strong phylogenetic signals (λ > 0.9 in some cases) for climate variables from both climate datasets, including temperature, soil temperature, solar radiation and precipitation. We were also able to impute missing bioclimatic envelopes for artificially removed species, having a correlation with observed data of.7. Main conclusions: We reconstructed plant climatic tolerances for >200,000 plant species historically recorded on GBIF using a technique that could be applied to any comparable biodiversity dataset. Although global information on most species is sparse, we explored methods for bias correction and data imputation, with positive results for both. [ABSTRACT FROM AUTHOR]

Aims: Terrestrial biodiversity is threatened by land use change. Modelling suggests that the remaining, potentially arable areas of natural intact vegetation (rNIV) of 9 of 35 global biodiversity hotspots may be converted to agriculture by 2050, committing their endemic species to extinction. Studies have shown that if the global population adopted a healthy, mostly plant based diet, agricultural area expansion can be reduced. We want to examine to what degree this applies to the regions covered by biodiversity hotspots. Location: Global. Time period: 2020–2050. Major taxa studied: No particular taxa. Methods: For every biodiversity hotspot, we simulate climate change impacts on agricultural productivity, and estimate food demand shifts from 2010 to 2050 by processing population and income growth projections. We quantify the net change in rNIV by 2050 in all hotspots by calculating the agricultural area necessary to meet the food demand under a business as usual, a healthy diet, a healthy diet plus agricultural intensification, and a healthy diet plus agricultural intensification plus crop change scenario. Results: In the healthy diet scenario, the rNIV of 16–21 hotspots can be preserved entirely, but 5–6 hotspots in less developed regions may lose all rNIV to agricultural area expansion. In these regions, a healthy diet implies an increase in consumed calories and no change in the already high share of plant‐based calories. When combined with agricultural intensification, these hotspots will still lose 7%–92% of rNIV. Only an additional change in crop mix patterns may preserve all. Main conclusions: While a change in dietary habits may be sufficient for preservation of rNIV in many hotspot regions, a healthy diet actually puts more pressure on rNIV in other hotspot regions. Intensifying agriculture and optimizing crop selection should be priorities in those regions to mitigate the expected loss of rNIV to agricultural expansion. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim To assess the potential impacts of future climate change on spatio-temporal patterns of freshwater fish beta diversity. Location Adour-Garonne River Basin (France). Methods We first applied an ensemble modelling approach to project annually the future distribution of 18 fish species for the 2010-2100 period on 50 sites. We then explored the spatial and temporal patterns of beta diversity by distinguishing between its two additive components, namely species turnover and nestedness. Results Taxonomic homogenization of fish assemblages was projected to increase linearly over the 21st century, especially in the downstream parts of the river gradient. This homogenization process was almost entirely caused by a decrease in spatial species turnover. When considering the temporal dimension of beta diversity, our results reveal an overall pattern of decreasing beta diversity along the upstream-downstream river gradient. In contrast, when considering the turnover and nestedness components of temporal beta diversity we found significant U-shaped and hump-shaped relationships, respectively. Main conclusions Future climate change is projected to modify the taxonomic composition of freshwater fish assemblages by increasing their overall similarity over the Adour-Garonne River Basin. Our findings suggest that the distinction between the nestedness and turnover components of beta diversity is not only crucial for understanding the processes shaping spatial beta-diversity patterns but also for identifying localities where the rates of species replacement are projected to be greatest. Specifically we recommend that future conservation studies should not only consider the spatial component of beta diversity but also its dynamic caused by climate warming. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Climate change could result in an increase in species richness because large-scale biogeography suggests that more species could be gained from equatorial regions than may be lost pole-ward. However, the colonization of newly available habitat may lag behind the rate dictated by climatic warming if there exists of a lack of connectivity between 'donor' and receiving areas. The objective of this study was to compare how regional warming affected the biodiversity of marine fish in areas that differed in their connectivity in the Baltic Sea. Location North-east Atlantic, Kattegat and Baltic Sea. Methods The total species richness and the mean species richness from scientific surveys were related to changes in temperature and salinity. Changes in the extent of the distribution of individual fish species were related to the latitudinal distribution, salinity tolerance, maximum body size and exploitation status to assess to what extent climate change and fishing impacts could explain changes in species richness in the Baltic. Results Rising temperatures in the well-connected Kattegat correlated to an increase in the species richness of fish, due to an increase in low-latitude species. Unexpectedly, species richness in the poorly connected Baltic Sea also increased. However, the increase seems to be related to higher salinity rather than temperature and there was no influx of low-latitude species. Main conclusions These results do not support the hypothesis that low-connectivity areas are less likely to see increases in species richness in response to warming. This indicates that the effect of climate change on biodiversity may be more difficult to predict in areas of low connectivity than in well-connected areas. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim This paper identifies socio-economic driving forces of biodiversity change and analyses their political and economic dynamics by modelling socio-economic parts of three scenario storylines developed for the ALARM (assessing large-scale risks for biodiversity with tested methods) project. In the BAMBU (business-as-might-be-usual) scenario policy decisions already made in the European Union (EU) are implemented and enforced, but no additional measures are introduced. The GRAS (growth applied strategy) scenario describes a future world orientated towards economic growth and complete deregulation. And finally, SEDG (sustainable European development goal) is a normative scenario focusing on the achievement of sustainable development. Methods The GINFORS (global inter-industry forecasting system) model is applied to quantify the effects of different sets of policy measures representing the three scenarios. It allows investigation of the inter-relations between socio-economic driving forces and the state of the environment. Results The presented results for the 25 EU countries focus on the following variables: unemployment, material extraction, energy supply and CO2 emissions. The lowest amount of unemployment is in the SEDG scenario, where it steadily decreases from 2005 to 2020. In BAMBU it falls to a level that is also below that of 2005. In GRAS, the number of unemployed people in 2020 is clearly over the value of 2005. The development of total material extraction from 2005 to 2020 is nearly stable in BAMBU, while it clearly increases in GRAS. Only in SEDG is there a reduction in resource use. None of the scenarios achieves a substantial reduction in energy use. However, the development of CO2 emissions shows a decoupling from energy supply. For BAMBU there is a slight decline in CO2 emissions over time, for GRAS they increase but with a slightly smaller growth rate than energy supply. In SEDG the emissions are reduced. The decoupling trends can be explained by a shift to more renewable energy sources in all scenarios, with the highest share in SEDG. Main conclusions The results indicate that a growth-oriented policy design, such as presented in the GRAS scenario, is not compatible with the conservation of biodiversity. Only in the SEDG scenario do the policy measures support the idea of a sustainable development, but in some respects they are still not ambitious enough. [ABSTRACT FROM AUTHOR]

Humid tropical alpine environments are crucial ecosystems that sustain biodiversity, biological processes, carbon storage and surface water provision. They are identified as one of the terrestrial ecosystems most vulnerable to global environmental change. Despite their vulnerability, and the importance for regional biodiversity conservation and socio-economic development, they are among the least studied and described ecosystems in the world. This paper reviews the state of knowledge about tropical alpine environments, and provides an integrated assessment of the potential threats of global climate change on the major ecosystem processes. Humid tropical alpine regions occur between the upper forest line and the perennial snow border in the upper regions of the Andes, the Afroalpine belt and Indonesia and Papua New Guinea. Climate change will displace ecosystem boundaries and strongly reduce the total area of tropical alpine regions. Displacement and increased isolation of the remaining patches will induce species extinction and biodiversity loss. Drier and warmer soil conditions will cause a faster organic carbon turnover, decreasing the below-ground organic carbon storage. Since most of the organic carbon is currently stored in the soils, it is unlikely that an increase in above-ground biomass will be able to offset soil carbon loss at an ecosystem level. Therefore a net release of carbon to the atmosphere is expected. Changes in precipitation patterns, increased evapotranspiration and alterations of the soil properties will have a major impact on water supply. Many regions are in danger of a significantly reduced or less reliable stream flow. The magnitude and even the trend of most of these effects depend strongly on local climatic, hydrological and ecological conditions. The extreme spatial gradients in these conditions put the sustainability of ecosystem management at risk. [ABSTRACT FROM AUTHOR]

Aim: Environmental variables are strongly tied to species occurrence and population growth, but approaches to predicting the location of deep‐sea species or their ability to withstand a changing environment stem primarily from presence data. We coupled environmental data with observed densities of deep‐sea habitat‐forming corals and sponges to determine the environmental variables and geomorphology that contributed best to their occurrence. Location: Northwest Atlantic. Time period: 2013 and 2014. Major taxa studied: Deep‐sea coral and sponge communities. Methods: Multivariate and univariate analyses were used to determine significant environmental contributors to densities of genera and families of corals and sponges. We then assessed the relationship of densities of genera and families of corals and sponges with environmental variables found to be significant contributors to their occurrence and to geomorphology. Results: Sponge and coral genera and families were influenced by different environment variables. Temperature, salinity and dissolved oxygen contributed to the occurrence of sponges, whereas seafloor properties of slope and substrate contributed to the occurrence of corals. Although individuals of corals and sponges were observed across a range of a contributing environmental variable, high densities were observed only in very narrow ranges. Main conclusions: Geomorphic setting is an effective approach for discerning the associations of coral with seabed features. High densities of coral and sponge genera and families restricted to narrow environmental ranges might be at greater risk of local extinction. Differences in the occurrence of coral and sponge genera and families with environmental conditions suggest that they will differentially respond to predicted environmental changes. As conditions in the deep sea change with ongoing changes in climate, population expansion might be limited owing to suboptimal conditions, and established populations might persist but might have fewer individuals or species, which might lead to a loss in biodiversity. [ABSTRACT FROM AUTHOR]

Motivation: More than half of Earth's species are contained in a mere 1.4% of its land area, but the climates of many of these biodiversity hotspots are projected to disappear as a consequence of anthropogenic climate change. There is growing recognition that spatio- temporal patterns of climate in biodiversity hotspots have shaped biological diversity over a variety of historical time- scales, yet these patterns are rarely taken into account in assessments of the vulnerability of biodiversity hotspots to future climate change. In our review, we synthesize the climatic processes that have led to the diversification of hotspots and interpret what this means in the context of anthropogenic climate change. We demonstrate the importance of mesoclimatic processes and fine- scale topographical heterogeneity, in combination with climatic variability, in driving speciation processes and maintaining high levels of diversity. We outline why these features of hotspots are crucial to understanding the impacts of anthropogenic climate change and discuss how recent advances in predictive modelling enable vulnerability to be understood better. Location: Global. Main conclusions: We contend that many, although not all, biodiversity hotspots have climate and landscape characteristics that create fine- scale spatial variability in climate, which potentially buffers them from climatic changes. Temporally, many hotspots have also experienced stable climates through evolutionary time, making them particularly vulnerable to future changes. Others have experienced more variable climates, which is likely to provide resilience to future changes. Thus, in order to identify risk for global biodiversity, we need to consider carefully the influence of spatio- temporal variability in climate. However, most vulnerability assessments in biodiversity hotspots are still reliant on climate data with coarse spatial and temporal resolution. Higher- resolution forecasts that account for spatio- temporal variability in climate and account better for the physiological responses of organisms to this variability are much needed to inform future conservation strategies. [ABSTRACT FROM AUTHOR]

Aim: A major goal in modern ecology is understanding the source of variation in species responses to anthropogenic change. Trait‐based approaches show promise, but traits found to be predictive in one study often fail in others. We seek to understand whether variation in traits' explanatory power comes about due to interaction effects—between multiple traits and between traits and the environment. We assess the context‐dependence of trait‐based responses to habitat conversion by testing the hypothesis that abundance in converted habitats decreases with arboreality, while including interactions with reproductive mode, a trait of known importance, and biologically relevant climate variables. Location: Global tropical forest biomes. Time period: 1997–2018. Major taxa studied: Amphibians. Methods: Using 18 studies of amphibian communities from across the globe, we evaluate the role of vertical niche position and reproductive mode in determining abundance within primary forest, structurally complex agriculture, and structurally simple agriculture. We examined interactions between traits, land‐use types and climate variables. Results: Average abundance steadily declined from primary forest, through complex agriculture, and was lowest in simple agriculture. Arboreality (high vertical niche position) leads to increased sensitivity to conversion of forest to simple agriculture, while terrestrial species are more sensitive when habitat is converted to complex agriculture. We found no evidence that trait‐by‐trait interactions determined abundance after habitat conversion. However, the effects of climate can alter how species' traits determine abundance patterns—while lentic amphibians maintain abundance after conversion regardless of climate zone, direct developers and lotic species become increasingly sensitive to habitat modification in warmer climates. Major conclusions: Vertical niche position acts as a limiting axis in modified environments, with response to conversion dependent on the availability of vegetative strata. Interactions between traits and the environment play a strong and underappreciated role in defining community composition in converted habitats. Such interactions may underlie the difficulties past studies have had in achieving generality across study locations and faunas. [ABSTRACT FROM AUTHOR]

Aim: Predictions for the future of coral reefs are largely based on thermal exposure and poorly account for potential geographic variation in biological sensitivity to thermal stress. Without accounting for complex sensitivity responses, simple climate exposure models and associated predictions may lead to poor estimates of future coral survival and lead to policies that fail to identify and implement the most appropriate interventions. To begin filling this gap, we evaluated a number of attributes of coral taxa and communities that are predicted to influence coral resistance to thermal stress over a large geographic range. Location: Western Indo‐Pacific and Central Indo‐Pacific Ocean Realms. Major taxa studied: Zooxanthellate Scleractinia – hard corals. Methods: We evaluated the geographic variability of coral resistance to thermal stress as the ratio of thermal exposure and sensitivity in 12 countries during the 2016 global‐bleaching event. Thermal exposure was estimated by two metrics: (a) historical excess summer heat (cumulative thermal anomaly, CTA), and (b) a multivariate index of sea‐surface temperature (SST), light, and water flow (climate exposure, CE). Sensitivity was estimated for 226 sites using coordinated bleaching observations and underwater surveys of coral communities. We then evaluated coral resistance to thermal stress using 48 generalized linear mixed models (GLMMs) to compare the potential influences of geography, historical SST variation, coral cover and coral richness. Results: Geographic faunal provinces and ecoregions were the strongest predictors of coral resistance to thermal stress, with sites in the Australian, Indonesian and Fiji‐Caroline Islands coral provinces having higher resistance to thermal stress than Africa‐India and Japan‐Vietnam provinces. Ecoregions also showed strong gradients in resistance with highest resistance to thermal stress in the western Pacific and Coral Triangle and lower resistance in the surrounding ecoregions. A more detailed evaluation of Coral Triangle and non‐Coral Triangle sites found higher resistance to thermal stress within the Coral Triangle, associated with c. 2.5 times more recent historical thermal anomalies and more centralized, warmer, and cool‐water skew SST distributions, than in non‐Coral Triangle sites. Our findings identify the importance of environmental history and geographic context in future predictions of bleaching, and identify some potential drivers of coral resistance to thermal stress. Main conclusions: Simple threshold models of heat stress and coral acclimation are commonly used to predict the future of coral reefs. Here and elsewhere we show that large‐scale responses of coral communities to heat stress are geographically variable and associated with differential environmental stresses and histories. [ABSTRACT FROM AUTHOR]

Aim: Urban biodiversity, and its associated ecosystem services, is an important component of the quality of life of urban residents. The "luxury effect" posits a positive association between biodiversity and socioeconomic status in urban areas, and is thus reflective of environmental injustice, as the benefits associated with biodiversity are not equitably shared across society. We aimed to determine the generality of the luxury effect, and to identify the factors causing its variation across published studies. Location: Urbanized landscapes globally. Time period: Current. Major taxa studied: Terrestrial animals and plants. Methods: We tested the luxury effect across a sample of 337 estimates of the relationship between biodiversity measures and socioeconomic status from 96 studies via a meta‐analysis, addressing three hypotheses: (a) the luxury effect is more pronounced where water availability is limited, (b) the luxury effect is more pronounced in developing than developed countries, (c) the luxury effect is stronger in exotic compared to native species. Results: There was a significant overall luxury effect: there was a positive association between terrestrial biodiversity measures and socioeconomic status. The strength of the luxury effect was greater in arid areas. There was limited support for a stronger luxury effect in exotic species, but no support for any association with development status. Main conclusions: Many key and emerging climate impacts are concentrated in urban areas. Therefore, the degree of environmental injustice represented by the luxury effect may be amplified in the future, especially in arid regions. The objective to increase urban biodiversity through more equitable management and provision of water resources could form part of a wider strategy for sustainable development of cities to promote environmental justice, enhancing the quality of life of urban residents across all sectors of society. Challenges remain to ensure that any such strategy prioritizes conservation goals for native biodiversity. [ABSTRACT FROM AUTHOR]

Abstract: Aim: The aim was to examine whether recent mortality can be explained by hydraulic failure linked to water deficit. Location: Western Europe. Time period: 1986–2014. Major taxa studied: Forty‐four tree species. Methods: We modelled the hydraulic safety margin (HSM) across the ranges of 44 tree species at their driest margin (n = 193,261 plots), defined as the difference between the estimated minimal soil water potential of each plot and the species water stress threshold, which corresponds to the hydraulic failure of the vascular system. Soil water potential was estimated by applying Campbell's equations on the minimal and maximal soil water contents estimated from 1979 to 2010 in the top 289 cm of soil and five soil textures across the species ranges. For each species, we modelled the amount of average mortality derived from plots of the Spanish and French National Forest Inventories to the variation in modelled hydraulic safety margin and environmental drivers across the species ranges using hurdle models. Results: We did not identify any global convergence of modelled HSM within the species distribution ranges, finding instead a rather large variability in modelled HSM for most of the studied species. Fifteen species, out of 25 for which the models were practicable, showed significantly higher mortality in populations with negative HSM in comparison to those showing positive HSM, with positive and negative interaction along the aridity index. Main conclusions: The combination of competition, average climate and modelled HSM explained average tree mortality. Most of the species presented at least one population that had already experienced a negative HSM and many other populations a positive but narrow HSM, suggesting that climate change is likely to push some populations towards a higher risk of hydraulic failure in the drier conditions projected for Western Europe. [ABSTRACT FROM AUTHOR]

Abstract: Aim: We analyse the latitudinal variation of range shape, testing whether ranges at higher latitudes or of larger size tend to be elongated in an east–west direction, as expected from climatic niche constraints. Additionally, we assess whether poleward range limits are less stochastic than equatorward limits. Location: Global; all terrestrial areas except Antarctica. Time period: Contemporaneous. Major taxa studied: Birds and mammals. Methods: We quantified the shape of the distribution ranges of 10,057 species of birds and 5,411 species of mammals, and assessed the relationship of range shape with latitude and range size using generalized additive models. The observed pattern was compared with that predicted by a null model, in which species ranges were constrained only by the shape of the landmasses. Furthermore, we divided each range in two polygons and measured their separate perimeters, to compare the limits of the poleward and equatorward portions of each range. Results: In terrestrial mammals and birds, only species living at higher latitudes in the Northern Hemisphere and with large range sizes have ranges that consistently tend to be elongated in an east–west direction. The difference between observed and null range shapes increases from the Southern Hemisphere and the tropics towards the north. The difference between equatorward and poleward semi‐perimeters was relevant only in the Southern Hemisphere, and it is probably explained by the shape of the continents. Main conclusions: The existence of a latitudinal gradient in range shape is consistent with a different role of deterministic and stochastic processes in the tropics versus high latitudes. Specifically, the results are in line with a scenario in which tropical niche conservatism and relatively evolutionarily labile lower thermal tolerance increase the relevance of climate in determining range limits towards the poles, with stochastic factors (e.g., dispersal limitation) more relevant in shaping low‐latitude range limits. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Across the planet, grass‐dominated biomes are experiencing shrub encroachment driven by atmospheric CO2 enrichment and land‐use change. By altering resource structure and availability, shrub encroachment may have important impacts on vertebrate communities. We sought to determine the magnitude and variability of these effects across climatic gradients, continents, and taxa, and to learn whether shrub thinning restores the structure of vertebrate communities. Location: Worldwide. Time period: Contemporary. Major taxa studied: Terrestrial vertebrates. Methods: We estimated relationships between percentage shrub cover and the structure of terrestrial vertebrate communities (species richness, Shannon diversity and community abundance) in experimentally thinned and unmanipulated shrub‐encroached grass‐dominated biomes using systematic review and meta‐analyses of 43 studies published from 1978 to 2016. We modelled the effects of continent, biome, mean annual precipitation, net primary productivity and the normalized difference vegetation index (NDVI) on the relationship between shrub cover and vertebrate community structure. Results: Species richness, Shannon diversity and total abundance had no consistent relationship with shrub encroachment and experimental thinning did not reverse encroachment effects on vertebrate communities. However, some effects of shrub encroachment on vertebrate communities differed with net primary productivity, amongst vertebrate groups, and across continents. Encroachment had negative effects on vertebrate diversity at low net primary productivity. Mammalian and herpetofaunal diversity decreased with shrub encroachment. Shrub encroachment also had negative effects on species richness and total abundance in Africa but positive effects in North America. Main conclusions: Biodiversity conservation and mitigation efforts responding to shrub encroachment should focus on low‐productivity locations, on mammals and herpetofauna, and in Africa. However, targeted research in neglected regions such as central Asia and India will be needed to fill important gaps in our knowledge of shrub encroachment effects on vertebrates. Additionally, our findings provide an impetus for determining the mechanisms associated with changes in vertebrate diversity and abundance in shrub‐encroached grass‐dominated biomes. [ABSTRACT FROM AUTHOR]

Abstract: Aim: The aim was to examine the links between past biome stability, vegetation dynamics and biodiversity patterns. Location: South America. Time period: Last 30,000 years. Major taxa studied: Plants. Methods: We classified South America into major biomes according to their dominant plant functional groups (grasses, trees and shrubs) and ran a random forest (RF) classification with data on current climate. We then fitted the algorithm to predict biome distributions for every 1,000 years back to 21,000 yr BP and estimated biome stability by counting how many times a change in climate was predicted to shift a grid cell from one biome to another. We compared our model‐based stability map with empirical estimates from selected pollen records covering the past 30 kyr in terms of vegetation shifts, changes in species composition and time‐lag of vegetation responses. Results: We found a strong correlation between our habitat stability map and regional vegetation dynamics. Four scenarios emerged according to the way forest distribution shifted during a climate change. Each scenario related to specific regional features of biome stability and diversity, allowing us to formulate specific predictions on how taxonomic, genetic and functional components of biodiversity might be impacted by modern climate change. Main conclusions: Our validated map of biome stability provides important baseline information for studying the impacts of past climate on biodiversity in South America. By focusing exclusively on climatic changes of manifested relevance (i.e., those resulting in significant habitat changes), it provides a novel perspective that complements previous datasets and allows scientists to explore new questions and hypotheses at the local, regional and continental scales. [ABSTRACT FROM AUTHOR]

Aim Global biomes are often classified by mean annual temperature and precipitation, but there is significant overlap between biomes, making it difficult to interpret the role of climate in the distribution of biomes globally. Climate predictability (including long-term reliability of both seasonality and inter-annual variability) varies considerably between biomes and regulates biodiversity distribution, adaptation and evolution, but its global pattern has rarely been investigated. The aim of this study was to characterize climatic space quantitatively for major biomes of the world using temperature and precipitation predictability, and to interpret its biological implications under future climate change. Location Global. Time Period 1901-2012. Methods We calculated global gridded temperature and precipitation predictability based on an information theory approach, and compared climatic spaces defined by these measures within and across biomes. Results We show that temperature predictability has a clear latitudinal gradient, whereas precipitation predictability is geographically variable. We further show that temperature and precipitation predictability form distinct climatic spaces for major biomes across the globe, and importantly, temperature and precipitation predictability can robustly distinguish biomes that are overlapping in mean annual climate statistics. Main conclusions Climatic space created by temperature and precipitation predictability supplements the traditional biome-specific climatic spaces created by annual mean temperature and total precipitation. Quantifying measures of climate predictability helps us to understand adaptation strategies adopted by local organisms within and across biomes. Our results show that quantifying climate predictability is a simple and effective way to delineate more robustly biome climate space and its influences on macroecology and evolutionary biology, which in turn could underpin conservation efforts under future climate change, especially when prevailing climates are comparable in terms of magnitude. [ABSTRACT FROM AUTHOR]

Aim Many competing hypotheses seek to identify the mechanisms behind species richness gradients. Yet, the determinants of species turnover over broad scales are uncertain. We test whether environmental dissimilarity predicts biotic turnover spatially and temporally across an array of environmental variables and spatial scales using recently observed climate changes as a pseudo-experimental opportunity. Location Canada. Methods We used an extensive database of observation records of 282 Canadian butterfly species collected between 1900 and 2010 to characterize spatial and temporal turnover based on Jaccard indices. We compare relationships between spatial turnover and differences in an array of relevant environmental conditions, including aspects of temperature, precipitation, elevation, primary productivity and land cover. Measurements were taken within 100-, 200- and 400-km grid cells, respectively. We tested the relative importance of each variable in predicting spatial turnover using bootstrap analysis. Finally, we tested for effects of temperature and precipitation change on temporal turnover, including distinctly accounting for turnover under individual species' potential dispersal limitations. Results Temperature differences between areas correlate with spatial turnover in butterfly assemblages, independently of distance, sampling differences or the spatial resolution of the analysis. Increasing temperatures are positively related to biotic turnover within quadrats through time. Limitations on species dispersal may cause observed biotic turnover to be lower than expected given the magnitude of temperature changes through time. Main conclusions Temperature differences can account for spatial trends in biotic dissimilarity and turnover through time in areas where climate is changing. Butterfly communities are changing quickly in some areas, probably reflecting the dispersal capacities of individual species. However, turnover is lower through time than expected in many areas, suggesting that further work is needed to understand the factors that limit dispersal across broad regions. Our results illustrate the large-scale effects of climate change on biodiversity in areas with strong environmental gradients. [ABSTRACT FROM AUTHOR]

Aim The impact of multiple stressors on biodiversity is one of the most pressing questions in ecology and biodiversity conservation. Here we critically assess how often and efficiently two main drivers of global change have been simultaneously integrated into research, with the aim of providing practical solutions for better integration in the future. We focus on the integration of climate change (CC) and land-use change (LUC) when studying changes in species distributions. Location Global. Methods We analysed the peer-reviewed literature on the effects of CC and LUC on observed changes in species distributions, i.e. including species range and abundance, between 2000 and 2014. Results Studies integrating CC and LUC remain extremely scarce, which hampers our ability to develop appropriate conservation strategies. The lack of CC-LUC integration is likely to be a result of insufficient recognition of the co-occurrence of CC and LUC at all scales, covariation and interactions between CC and LUC, as well as correlations between species thermal and habitat requirements. Practical guidelines for the study of these interactive effects include considering multiple drivers and processes when designing studies, using available long-term datasets on multiple drivers, revisiting single-driver studies with additional drivers or conducting comparative studies and meta-analyses. Combining various methodological approaches, including time lags and adaptation processes, represent further avenues to improve global change science. Main conclusions Despite repeated claims for a better integration of multiple drivers, the effects of CC and LUC on species distributions and abundances have been mostly studied in isolation, which calls for a shift of standards towards more integrative global change science. The guidelines proposed here will encourage study designs that account for multiple drivers and improve our understanding of synergies or antagonisms among drivers. [ABSTRACT FROM AUTHOR]

Aim To examine the relationship between island characteristics (area, distance to the nearest continent, climate and human population size) and ant species richness, as well as the factors underlying global geographical clustering of native and exotic ant composition on islands. Location One hundred and two islands from 20 island groups around the world. Methods We used spatial linear models that consider the spatial structure of islands to examine patterns of ant species richness. We also performed modularity analyses to identify clusters of islands hosting a similar suite of species and constructed conditional inference trees to assess the characteristics of islands that explain the formation of these island-ant groups. Results Island area was the best predictor of ant species richness. However, distance to the nearest continent was an important predictor of native ant species richness, as was human population size for exotic species richness. Native species appear slightly more modulated (i.e. well grouped in species assemblages that are present over a distinct cluster of islands) than are exotic species. Exotic species, while still exhibiting some modularity, tended to be widely distributed among island groups. Interestingly, ocean currents accounted for most of the variation in modularity and thus species composition for both native and exotic ant species. Main conclusions Contrary to previous work, both native and exotic species appeared to be confined to particular island regions, and patterns in the distribution of both native and exotic species were limited by a similar suite of factors. However, the distribution of exotic ant species appeared to be more influenced by human-related variables and less structured relative to those of native ant species, perhaps due to the long-term (and increasing) influence of human-mediated dispersal that favours exotic species. [ABSTRACT FROM AUTHOR]

Aim The use of atlas data in combination with a variety of modelling approaches has become a common practice in species distribution studies. The spatial extent over which species distribution models ( SDMs) should be fitted (i.e. the spatial extent) is often arbitrary and coincides with the extent of the atlases. In order to develop reliable SDMs using species atlas data, we propose an approach that incorporates the taxonomy of species and therefore delineates the spatial extent for SDMs. Location Mainland Spain. Methods We used atlas data to generate taxonomically delineated datasets for 365 terrestrial species. The presence records in the datasets were identical to those in the atlas, while the absence records were delimited to the presence of at least one species in the same family or order. We also generated two randomly delineated datasets that were the same size as the taxonomically delineated datasets. We assessed the predictive performance of the SDMs specifically by studying the model calibration ( Miller's statistic) and discrimination capacity (area under the curve of the receiver operating characteristic plot), along with the geographical similarity pattern of the predicted maps. Results The models that were trained using the taxonomically delineated datasets produced significantly improved models in terms of calibration, while their discrimination capacity was no greater than that of the models trained using the atlas dataset. The improvements to the calibration of the taxonomically delineated datasets were significantly greater than those with random absence sets. Main conclusion Delineating the spatial extent using taxonomical information leads to a significant improvement in the model performance of SDMs. This restriction can reduce the effect of environmental events beyond the species history during model parameterization, thus allowing the models obtained to more precisely depict the potential distribution of the species. We therefore recommend considering the delineation of spatial extent using species taxonomy when atlas data are employed in SDMs. [ABSTRACT FROM AUTHOR]

Aim Fossil records are being increasingly used to help understand the consequences of climate change for biodiversity. Pollen records from the late Quaternary are among the most commonly used fossil data, but pollen-based inferences of biodiversity can potentially be confounded by spatial and taxonomic uncertainties and the influence of non-climatic abiotic factors such as soils on vegetation-climate relationships. Using paired pollen and vegetation inventories, we assess the fidelity of pollen-based estimates of compositional turnover of vegetation along environmental gradients given various sources of uncertainty. Location Eastern United States. Methods We used modern pollen records and forest composition data from Forest Inventory and Analysis ( FIA) plots to fit generalized dissimilarity models. To address how uncertainties in pollen records affect estimates of turnover, we coarsened the vegetation data spatially from individual plots to 10- and 30-arcmin resolution and taxonomically from species to genus. To determine whether soil properties influenced turnover, we used deviance partitioning between models including climate or soil variables versus models with a combination of both. Results Pollen-based estimates of turnover were highly correlated with those based on FIA data, but tended to be lower, mainly due to differences in taxonomic resolution and secondarily to differences in spatial resolution. Neither spatial nor taxonomic uncertainty substantially reduced the correlation between pollen- and FIA-based estimates of turnover. FIA data best matched pollen records when they were aggregated to genus and 30-arcmin resolution. Vegetation-climate relationships were similar across datasets, although models sometimes differed. The influence of soil variables was negligible compared with climate variables and did not improve model fit. Pollen thresholds did not greatly affect the form and strength of pollen-vegetation relationships. Main conclusions Pollen can act as a robust proxy for vegetation turnover, thereby supporting the use of pollen-based estimates of turnover to predict temporal changes in vegetation. [ABSTRACT FROM AUTHOR]

Aim Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change. Location Mediterranean terrestrial ecosystems. Methods This article revisits the research priorities proposed in a 1998 assessment. Results A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between C storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest-atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology. Main conclusions (1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional- and global-scale models that are more tightly connected with large-scale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use. [ABSTRACT FROM AUTHOR]

Aim Despite considerable attention to climate change, no global assessment of the consequences of sea level rise is available for insular ecosystems. Yet, over 180,000 islands world-wide contain 20% of the world's biodiversity. We investigated the consequences of sea level rise for the 10 insular biodiversity hotspots world-wide and their endemic species. This assessment is crucial to identify areas with the highest risk of inundation and the number of endemic species at risk of potential extinction. Location Ten insular biodiversity hotspots including the Caribbean islands, the Japanese islands, the Philippines, the East Melanesian islands, Polynesia- Micronesia, Sundaland, Wallacea, New Caledonia, New Zealand and Madagascar and the Indian Ocean islands (i.e. 4447 islands). Methods We investigated four scenarios of projected sea level rise (1, 2, 3 and 6 m) on these islands. For each scenario, we assessed the number of islands that would be entirely and partially submerged by overlying precise digital elevation model and island data. We estimated the number of endemic species for each taxon (i.e. plants, birds, reptiles, mammals, amphibians and fishes) potentially affected by insular habitat submersion using the endemic-area relationship. Results Between 6 and 19% of the 4447 islands would be entirely submerged under considered scenarios (1-6 m of sea level rise). Three hotspots displayed the most significant loss of insular habitat: the Caribbean islands, the Philippines and Sundaland, representing a potential threat for 300 endemic species. Main conclusions With the current estimates of global sea level rise of at least 1 m by 2100, large parts of ecosystems of low-lying islands are at high risk of becoming submerged, leading to significant habitat loss world-wide. Therefore, the threat posed by sea level rise requires specific policies that prioritize insular biota on islands at risk as a result of near future sea level rise. [ABSTRACT FROM AUTHOR]

Aim Our aims were: (1) to separately evaluate the elevational patterns of β-diversity for nestedness, species richness difference and replacement, (2) to identify the drivers of β-diversity patterns by testing the effect of geographical and environmental distance (human population, temperature and land-use), and (3) to compare the response on native versus alien species to elucidate mechanisms of community assembly along elevational gradients. Location Two mountain regions ( Bergamo- Brescia and Trento) in the Italian Alps. Methods We used two floristic datasets in which species composition was sampled within two regular grids. First, we extracted species elevational range and quantified species composition nestedness along the elevational gradient. Second, we partitioned β-diversity into its species richness difference and replacement components and tested drivers using regression on distance matrix and hierarchical partitioning. All analyses were performed on natives and aliens, separately. Results For aliens, we found lack of mountain specialists (i.e. species with a distribution range restricted to high elevations), large nestedness, large species richness difference and low species replacement between low and high elevations. All findings point in the same direction: a great majority of alien species were introduced to the lowlands and only a subset of this community spread up the mountains. Both human pressures and temperature selection were important processes underpinning the observed filtering, while geographical and land-use distances were not important. Natives present contrasting patterns with large replacement along the elevation gradients indicating different mechanisms of community assembly. Main conclusions The relatively large alien species replacement in the lowlands indicated the presence of a pool of species that may potentially invade the temperate mountains in the future. Investigations of the identity of alien species occurring in the lowlands and their climatic pre-adaptation might provide tools to prevent invasions in the mountains by predicting the potential invaders and their future elevational distribution. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim We address the unexplored question of whether the lack of information on intra-specific diversity inherent in species-level niche modelling might bias evaluation of the conservation requirements of species and phylogeographic lineages under changing climates. We test for directional biases that might arise due to these methodological differences in ways of assessing risks from climate change. Location The African continent. Methods We identified from peer-reviewed studies that used both nuclear and plastid markers the distribution of deep phylogeographic divisions within nine species of African mammals and their phylogeographic lineages. We fitted ecological niche models to describe currently suitable, occupied climates and to project the shift of suitable climate to two future time slices. We applied gap analysis to reveal potential changes in the protection of phylogeographic diversity owing to climatic shifts. Results We found that, within species, most phylogeographic lineages differ in the climates they experience and have substantial geographic separation. Models that do not distinguish these subspecific units often fail to identify potential risks of climate change to lineages. Modelled potential effects of climate change on the geographic extent of suitable climate vary in both direction and magnitude. Predictions of the persistence of suitable climate in current protected areas for the resident lineages differ on average by factor of 2 between species and lineage models. Main conclusions Our study develops an original synthetic approach by combining niche modelling, projected climate change, phylogeographic information and gap analysis. We clearly identify the potential benefits of using the new approach to evaluate risks to the conservation of intra-specific genetic diversity that are posed by climate change. Our results suggest that prudent conservation strategies need to incorporate potential differences in climate tolerance among lineages when planning conservation measures for species confronted with environmental change. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Small (< 1 km2) alpine glaciers are likely to disappear in this century, resulting in decreased regional habitat heterogeneity in associated streams. Both heterogeneity within and spatial isolation among glacier-influenced streams can enhance beta diversity of stream-dwelling organisms. We measured beta at both community and population-genetic levels within and among streams currently influenced by small Pyrenean glaciers. We aimed to evaluate whether patterns are analogous between the two levels, to apply various approaches for characterizing beta, and to infer the outcome of future glacier loss on regional biodiversity. Location Four glacier-fed basins in the Parc National des Pyrénées, France. Methods We classified each of 18 stream reaches across the basins into either high-, mid- or low-'glaciality' (glacial influence) groups according to four physicochemical characteristics. At each reach, we collected macroinvertebrate communities and evaluated mitochondrial DNA haplotypes for 11-13 individuals of Baetis alpinus Pictet. Using taxa/haplotypes as basic units, we evaluated community and population-genetic beta diversity simultaneously. We measured beta diversity in three major ways: as multivariate (Sørensen's dissimilarity, Jost D) and 'classical' (gamma/alpha) variation to compare among glaciality groups, and as turnover along the glaciality gradient within each basin. Results For most approaches at both organizational levels, beta was greatest among high-glaciality reaches, absolute values of variation of beta in high-glaciality streams were strikingly similar between levels, and the steepest turnover within basins occurred between high- and mid-glaciality reaches. Therefore, high-glaciality reaches contained assemblages and populations that were unique both within that stream type (among basins) and compared with other stream types within basins. Main conclusions Parallel beta diversity patterns at population-genetic and community levels suggested that environmental drivers influence these levels analogously. Extreme conditions (e.g. low temperature, high instability, isolation) in high-glaciality streams probably enhance beta at both levels. Stream beta diversity is likely to decrease substantially with continued glacial reduction in this system. [ABSTRACT FROM AUTHOR]

Aim To assess whether the water availability measures commonly used in species distribution models might be misleading because they do not account for the hydrological effects of changes in vegetation structure and functioning. Location Europe. Methods We compared different methods for estimating water availability in species distribution models with the soil water content predicted by a process-based ecosystem model. The latter also accounted for the hydrological effects of dynamic changes in vegetation structure and functioning, including potential physiological effects of increasing CO2. Results All proxies showed similar patterns of water availability across Europe for current climate, but when projected into the future, the changes in the simpler water availability measures showed no correlation with those projected by the more complex ecosystem model, even if CO2 effects were switched off. Main conclusions Results from species distribution modelling studies concerning future changes in species ranges and biodiversity should be interpreted with caution, and more process-based representations of the water balance of terrestrial ecosystems should be considered within these models. [ABSTRACT FROM AUTHOR]

Aim To examine patterns of avian frugivory across clades, geography and environments. Location Global, including all six major biogeographical realms (Afrotropics, Australasia, Indo-Malaya, Nearctic, Neotropics and Palaearctic). Methods First, we examine the taxonomic distribution of avian frugivory within orders and families. Second we evaluate, with traditional and spatial regression approaches, the geographical patterns of frugivore species richness and proportion. Third, we test the potential of contemporary climate (water–energy, productivity, seasonality), habitat heterogeneity (topography, habitat diversity) and biogeographical history (captured by realm membership) to explain geographical patterns of avian frugivory. Results Most frugivorous birds (50%) are found within the perching birds (Passeriformes), but the woodpeckers and allies (Piciformes), parrots (Psittaciformes) and pigeons (Columbiformes) also contain a significant number of frugivorous species (9–15%). Frugivore richness is highest in the Neotropics, but peaks in overall bird diversity in the Himalayan foothills, the East African mountains and in some areas of Brazil and Bolivia are not reflected by frugivores. Current climate explains more variance in species richness and proportion of frugivores than of non-frugivores whereas it is the opposite for habitat heterogeneity. Actual evapotranspiration (AET) emerges as the best single climatic predictor variable of avian frugivory. Significant differences in frugivore richness and proportion between select biogeographical regions remain after differences in environment (i.e. AET) are accounted for. Main conclusions We present evidence that both environmental and historical constraints influence global patterns of avian frugivory. Whereas water–energy dynamics possibly constrain frugivore distribution via indirect effects on food plants, regional differences in avian frugivory most likely reflect historical contingencies related to the evolutionary history of fleshy fruited plant taxa, niche conservatism and past climate change. Overall our results support an important role of co-diversification and environmental constraints on regional assembly over macroevolutionary time-scales. [ABSTRACT FROM AUTHOR]

Aim Climate change may cause loss of genetic diversity. Here we explore how a multidisciplinary approach can be used to infer effects of past climate change on species distribution and genetic diversity and also to predict loss of diversity due to future climate change. We use the arctic-alpine plant Salix herbacea L. as a model. Location Europe, Greenland and eastern North America. Methods We analysed 399 samples from 41 populations for amplified fragment length polymorphism (AFLP) to identify current patterns of genetic structure and diversity and likely historical dispersal routes. Macrofossil records were compiled to infer past distribution, and species distribution models were used to predict the Last Glacial Maximum (LGM) and future distribution of climatically suitable areas. Results We found strong genetic differentiation between the populations from Europe/East Greenland and those from Canada/West Greenland, indicating a split probably predating the LGM. Much less differentiation was observed among the four genetic groups identified in Europe, and diversity was high in the Scandinavian as well as in southern alpine populations. Continuous distribution in Central Europe during the last glaciation was inferred based on the fossil records and distribution modelling. A 46–57% reduction in suitable areas was predicted in 2080 compared to present. However, mainly southern alpine populations may go extinct, causing a loss of about 5% of the genetic diversity in the species. Main conclusions From a continuous range in Central Europe during the last glaciation, northward colonization probably occurred as a broad front maintaining diversity as the climate warmed. This explains why potential extinction of southern populations by 2080 will cause a comparatively low loss of the genetic diversity in S. herbacea. For other species with different glacial histories, however, the expected climate-change induced regional extinction may cause a more severe loss of genetic diversity. We conclude that our multidisciplinary approach may be a useful tool for assessing impact of climate change on loss of genetic diversity. [ABSTRACT FROM AUTHOR]

Aim To describe the distribution of biodiversity and endemism of bryozoans in southern temperate and polar waters. We hypothesized that we would find: (1) no strong latitudinal richness gradient; (2) striking contrasts in richness and endemism between clades and between regions; and (3) that faunal similarity of regions would cluster geographically around each southern continent. Location South Atlantic, Indian and Pacific Oceans and the Southern Ocean. Methods We constructed a data base from known literature, regional data bases and recent finds. We regionalized each southern continent, calculated levels of richness and endemism for each region and continent, and usedprimer 5 to perform multivariate statistical analysis. Results A third (1681) of global bryozoan species described occur south of 30° S, of which c. 87% were cheilostomes. In richness we found no latitudinal cline and change across longitude was stronger. New Zealand was richest and had the most (60%) endemic species, followed by Antarctica at 57%. There were striking contrasts in regional richness and endemism between clades but the highest levels of between-region similarity were around Antarctica. The timing of past continent connectivity was reflected. Main conclusions Bryozoans show strong hemispherical asymmetry in richness and, like molluscs and corals, decrease away from Australasia rather than with latitude. Species endemism is much lower in Antarctic bryozoans than previously thought, and as this taxon is not particularly dispersive and is now amongst the best studied regionally, maybe Antarctic endemism in general is lower and Antarctica less cut-off to species dispersal than previously thought. However, Antarctic generic endemism is double the level previously calculated and regional faunal similarities are much higher than around other continents – both reflecting long-term isolation. Bryozoans, in contrast to the paradigm of Antarctic fauna, may be fairly robust to predicted climate change. Paradoxically, they may also be one of the best taxa to monitor to sensitively detect marine benthic responses. [ABSTRACT FROM AUTHOR]

Aim Over the next 100 years, human-driven climate change and resulting changes in species occurrences will have global impacts on biodiversity, ecosystem function, and human health. Here we examine how climate change may affect the occurrences of tick species in Africa and alter the suitability of habitat outside Africa for African ticks. Location Africa and the world. Methods We predicted continental and global changes in habitat suitability for each of 73 African tick species, using multiple regression models in different climate change scenarios that cover a wide range of uncertainty. Results Global habitat suitability improves for nearly all tick species under each of a representative range of eight climate change scenarios. Depending on the scenario, African tick species experience an average increase in global habitat suitability of between 1 million and 9 million square kilometres between 1990 and 2100. Main conclusions The potential for successful translocations of ticks and their pathogens from Africa to the rest of the world is likely to increase over the next 100 years. Although the general trend is one of range expansion, there are winners and losers among tick species in each scenario, suggesting that tick community composition will be disrupted substantially by climate change. If this is also typical of other invertebrates, then climate change will disrupt not only the geographic location of communities but also their structure. Changes in tick communities are also likely to influence tick-borne pathogens. [ABSTRACT FROM AUTHOR]

Recent work indicates that desert assemblages have elevated beta (β) diversity (between-locality turnover of species composition). This study compares β diversities between the Great Basin and the Great Plains of the western USA over the last 17 Myr. Today, the Great Basin is a topographically diverse desert scrubland to woodland and the Great Plains are low-relief temperate grassland, but 17 Ma they were more similar in topography, climate and land cover. A georeferenced database of mammal occurrences, complied from several sources, is used to test two hypotheses for the elevation of Great Basin β diversity: (1) that tectonic change of the topography has driven increased habitat packing in high- and low-elevation habitats, and (2) that climatic cycling in the Pleistocene has driven faunas from neighbouring provinces to overlap in the region. The Great Basin of the USA, centred on Nevada, and the central Great Plains of the USA, centred on Nebraska. Mammalian faunal lists compiled from published records and the records of many museums, available online, were partitioned into time-slices ranging from the recent to 17 Myr old. Beta diversity was calculated for each time-slice in two ways: multiplicative β diversity using first-order jackknife richness, and additive beta diversity using Simpson's evenness. Beta diversity is elevated in Nevada relative to Nebraska today. Beta diversity has been higher in the Great Basin since the Pleistocene and possibly since the late Early Hemphillian ( c. 7 Ma). Beta diversity in the Late Barstovian ( c. 13.5 Ma) of the Great Plains was higher even than β diversity in the Great Basin of today. The elevated β diversity in the Hemphillian supports the tectonic change hypothesis. The patterns of β diversity in the Recent, Pleistocene and Hemphillian all suggest that local-scale processes are important. The β diversity of the Late Barstovian Great Plains supports other studies indicating increased primary productivity or species packing. [ABSTRACT FROM AUTHOR]

To model long-term trends in plant species distributions in response to predicted changes in global climate.Amazonia.The impacts of expected global climate change on the potential and realized distributions of a representative sample of 69 individual Angiosperm species in Amazonia were simulated from 1990 to 2095. The climate trend followed the HADCM2GSa1 scenario, which assumes an annual 1% increase of atmospheric CO2 content with effects mitigated by sulphate forcing. Potential distributions of species in one-degree grid cells were modelled using a suitability index and rectilinear envelope based on bioclimate variables. Realized distributions were additionally limited by spatial contiguity with, and proximity to, known record sites. A size-structured population model was simulated for each cell in the realized distributions to allow for lags in response to climate change, but dispersal was not included.In the resulting simulations, 43% of all species became non-viable by 2095 because their potential distributions had changed drastically, but there was little change in the realized distributions of most species, owing to delays in population responses. Widely distributed species with high tolerance to environmental variation exhibited the least response to climate change, and species with narrow ranges and short generation times the greatest. Climate changed most in north-east Amazonia while the best remaining conditions for lowland moist forest species were in western Amazonia.To maintain the greatest resilience of Amazonian biodiversity to climate change as modelled by HADCM2GSa1, highest priority should be given to strengthening and extending protected areas in western Amazonia that encompass lowland and montane forests. [ABSTRACT FROM AUTHOR]

Theoretical work suggests that species’ ecological niches should remain relatively constant over long-term ecological time periods, but empirical tests are few. We present longitudinal studies of 23 extant mammal species, modelling ecological niches and predicting geographical distributions reciprocally between the Last Glacial Maximum and present to test this evolutionary conservatism. This study covered distributional shifts in mammal species across the lower 48 states of the United States. We used a machine-learning tool for modelling species’ ecological niches, based on known occurrences and electronic maps summarizing ecological dimensions, to assess the ability of ecological niches as modelled in one time period to predict the geographical distribution of the species in another period, and vice versa. High intertemporal predictivity between niche models and species’ occurrences indicate that niche conservatism is widespread among the taxa studied, particularly when statistical power is considered as a reason for failure of reciprocal predictions. Niche projections to the present for 8 mammal taxa that became extinct at the end of the Pleistocene generally increased in area, and thus do not support the hypothesis of niche collapse as a major driving force in their extinction. Ecological niches represent long-term stable constraints on the distributional potential of species; indeed, this study suggests that mammal species have tracked consistent climate profiles throughout the drastic climate change events that marked the end of the Pleistocene glaciations. Many current modelling efforts focusing on anticipating climate change effects on species’ potential geographical distributions will be bolstered by this result — in essence, the first longitudinal demonstration of niche conservatism. [ABSTRACT FROM AUTHOR]