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Aim In this paper, we applied the concept of 'hierarchical filters' in community ecology to model marine species distribution at nested spatial scales. Location Global, Mediterranean Sea and the Gulf of Gabes ( Tunisia). Methods We combined the predictions of bioclimatic envelope models ( BEMs) and habitat models to assess the current distribution of 20 exploited marine species in the Gulf of Gabes. BEMs were first built at a global extent to account for the full range of climatic conditions encountered by a given species. Habitat models were then built using fine-grained habitat variables at the scale of the Gulf of Gabes. We also used this hierarchical filtering approach to project the future distribution of these species under both climate change (the A2 scenario implemented with the Mediterranean climatic model NEMOMED8) and habitat loss (the loss of Posidonia oceanica meadows) scenarios. Results The hierarchical filtering approach predicted current species geographical ranges to be on average 56% smaller than those predicted using the BEMs alone. This pattern was also observed under the climate change scenario. Combining the habitat loss and climate change scenarios indicated that the magnitude of range shifts due to climate change was larger than from the loss of P. oceanica meadows. Main conclusions Our findings emphasize that BEMs may overestimate current and future ranges of marine species if species-habitat relationships are not also considered. A hierarchical filtering approach that accounts for fine-grained habitat variables limits the uncertainty associated with model-based recommendations, thus ensuring their outputs remain applicable within the context of marine resource management. [ABSTRACT FROM AUTHOR]

ABSTRACT Modelling strategies for predicting the potential impacts of climate change on the natural distribution of species have often focused on the characterization of a species’ bioclimate envelope. A number of recent critiques have questioned the validity of this approach by pointing to the many factors other than climate that play an important part in determining species distributions and the dynamics of distribution changes. Such factors include biotic interactions, evolutionary change and dispersal ability. This paper reviews and evaluates criticisms of bioclimate envelope models and discusses the implications of these criticisms for the different modelling strategies employed. It is proposed that, although the complexity of the natural system presents fundamental limits to predictive modelling, the bioclimate envelope approach can provide a useful first approximation as to the potentially dramatic impact of climate change on biodiversity. However, it is stressed that the spatial scale at which these models are applied is of fundamental importance, and that model results should not be interpreted without due consideration of the limitations involved. A hierarchical modelling framework is proposed through which some of these limitations can be addressed within a broader, scale-dependent context. [ABSTRACT FROM AUTHOR]

Aim: Significant changes in species elevational ranges in mountains have been repeatedly documented, yet the direction, magnitude and drivers of these shifts remain controversial. Presently, there is still lacking evidence about the general nature of species elevational range shifts in eastern Eurasia in response to anthropogenic climate change. By using historical specimen records and recent field observations for 735 seed plant species across 29 China's mountains, we assessed changes in species' elevational centroids and their drivers. Location: China. Time Period: 1950–2018. Major Taxa Studied: Seed plant species. Methods: The elevation records of all sampled occurrences in each mountain during the two time periods were estimated, and the null models were developed to test the sampling bias. Ecological niche models (ENMs) were used to evaluate the relative importance of climate factors in constraining each species distribution. Generalized linear models (GLMs) to test the relationships between the centroid elevational range shifts of species and different divers. Results: We found that 54% of the species shifting upward and 46% downhill. However, species' elevational shifts significantly differed among species and mountains. Herbaceous and lowland species moved upward faster than woody and high‐elevation species. Species in temperate mountains and in mountains with taller elevational gradients moved upward, while species in subtropical mountains and in mountains with shorter elevational gradients moved downward. Precipitation changes experienced by species, species' climatic adaptations, several species' functional traits and mountain size all contributed to explain the magnitude of species' centroid elevational range shifts. Main Conclusions: Our results highlight complex biodiversity redistribution of seed plants across Chinese mountains, not necessarily conforming to the trend of species upward shifts in elevation. Changes in precipitation regimes may blur the simplistic assumption of isotherm tracking. This study fills an important geographic shortfall for our understanding of biodiversity redistribution under anthropogenic climate change. [ABSTRACT FROM AUTHOR]

Aim: Global declines in structurally complex habitats are reshaping both land‐ and seascapes in directions that affect the responses of biological communities to warming. Here, we test whether widespread loss of kelp habitats through sea urchin overgrazing systematically changes the sensitivity of fish communities to warming. Location: Global temperate latitudes. Time period: Modern. Major taxa studied: Fishes. Methods: Community shifts in thermal affinity related to habitat were assessed by simulating and comparing fish communities from 2271 surveys across 15 ecoregions. Results: We found that fishes in kelp and urchin barrens differed in realized thermal affinities and range sizes, but only in regions where species pools had high variability in the thermal affinities of species. Barrens on warm temperate reefs host relatively more warm‐affinity fish species than neighbouring kelp beds, highlighting the acceleration of tropicalization processes facilitated by urchin grazing. In contrast, proportionally more cool‐affinity fishes colonize barrens at high temperate latitudes, contributing to community lags with ocean warming in these regions. Main conclusions: Our findings implicate urchins as drivers of ecological change, in part by affecting ecological resilience to warming. [ABSTRACT FROM AUTHOR]

Aim: The abundances and distributions of some species are more closely matched to variations in climate than others. Species traits that might influence how well the distribution and abundance of a species are matched to climatic variation include life history (e.g., body size and dispersal ability), ecology (e.g., habitat specialization and territoriality) and demography (e.g., population size). Here, we used a survey of bird abundances across the USA to assess the extent to which species abundances and distributions are predicted by climate (i.e., climate matching) and how species traits relate to interspecific variation in climate matching. Location: USA. Time period: 1983–2018. Major taxa studied: Birds. Methods: Species abundances were obtained from the North American Breeding Bird Survey. Climate matching was estimated as the predictive performance of species–climate models fitted using boosted regression trees and generalized additive models and modelled as a function of species traits. Results: Species traits explained 56% of the variation in climate matching among species. Intermediate‐sized species were more well matched to climate than smaller or larger species, as were species that lived primarily in forested compared with open habitats, species that were locally more abundant and species that were more territorial. Alternatively, species that were more specialized or had high variability in abundance among sites were less well matched to climate. We also found that species classified as "near threatened" were more well matched to climate, suggesting that these species might be more vulnerable to climate change. However, species classified as "vulnerable" were more decoupled from climate than those of "least concern", possibly owing to ecological drift associated with progressive population declines. Main conclusions: Our findings provide an ecological basis for understanding the extent to which species abundances and distributions match broad climatic gradients, which can provide the groundwork to improve our ability to predict distributions under global change. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim To explore global patterns of riverine fish endemism by applying an island biogeography framework to river drainage basins and highlight evolutionary mechanisms producing two kinds of endemism: neo-endemism, arising from within-drainage cladogenetic speciation, and palaeo-endemism, arising from species range contraction or anagenetic speciation. Location World-wide. Methods We use a uniquely comprehensive data set of riverine fish species distributions to map global fish endemism patterns. We then use the relationships between (1) total species richness and proportions of endemic species and (2) total species richness and a measure of in situ (i.e. within-drainage basin) probability of speciation by cladogenesis, to identify the two distinct forms of endemism. After separating drainage basins into two different sets according to dominance of one of these two forms, we apply a model averaging procedure to highlight, for both datasets, the environmental and historical variables that better explain endemism patterns. We finally analyse the effect of biotic components related to dispersal ability on the percentages of both kinds of endemism among lineages. Results Our results indicate that the two types of endemism are distributed differently across space and taxonomic lineages: (1) neo-endemism, positively related to the overall richness of the drainage basin, is essentially linked to in situ cladogenetic speciation and is positively related to drainage basin area, negatively related to climate variability since glacial periods and negatively related to all proxies of dispersal ability; and (2) palaeo-endemism, not directly contributing to drainage basin richness, is a pure process of extinction through range contraction and/or isolation through time and is mostly related to geographic isolation, glacial history and positively related to marine-derived origin of families. Main conclusions The non-random spatial and taxonomic distribution of neo-endemism and palaeo-endemism sharply reflects the role of evolutionary processes and provides a way to identify areas of high conservation interest based on their high present and future diversification potential. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Concerns over how global change will influence species distributions, in conjunction with increased emphasis on understanding niche dynamics in evolutionary and community contexts, highlight the growing need for robust methods to quantify niche differences between or within taxa. We propose a statistical framework to describe and compare environmental niches from occurrence and spatial environmental data. Location Europe, North America and South America. Methods The framework applies kernel smoothers to densities of species occurrence in gridded environmental space to calculate metrics of niche overlap and test hypotheses regarding niche conservatism. We use this framework and simulated species with pre-defined distributions and amounts of niche overlap to evaluate several ordination and species distribution modelling techniques for quantifying niche overlap. We illustrate the approach with data on two well-studied invasive species. Results We show that niche overlap can be accurately detected with the framework when variables driving the distributions are known. The method is robust to known and previously undocumented biases related to the dependence of species occurrences on the frequency of environmental conditions that occur across geographical space. The use of a kernel smoother makes the process of moving from geographical space to multivariate environmental space independent of both sampling effort and arbitrary choice of resolution in environmental space. However, the use of ordination and species distribution model techniques for selecting, combining and weighting variables on which niche overlap is calculated provide contrasting results. Main conclusions The framework meets the increasing need for robust methods to quantify niche differences. It is appropriate for studying niche differences between species, subspecies or intra-specific lineages that differ in their geographical distributions. Alternatively, it can be used to measure the degree to which the environmental niche of a species or intra-specific lineage has changed over time. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Species distribution modelling is commonly used to guide future conservation policies in the light of potential climate change. However, arbitrary decisions during the model-building process can affect predictions and contribute to uncertainty about where suitable climate space will exist. For many species, the key climatic factors limiting distributions are unknown. This paper assesses the uncertainty generated by using different climate predictor variable sets for modelling the impacts of climate change. Location Europe, 10° W to 50° E and 30° N to 60° N. Methods Using 1453 presence pixels at 30 arcsec resolution for the great bustard ( Otis tarda), predictions of future distribution were made based on two emissions scenarios, three general climate models and 26 sets of predictor variables. Twenty-six current models were created, and 156 for both 2050 and 2080. Map comparison techniques were used to compare predictions in terms of the quantity and the location of presences (map comparison kappa, MCK) and using a range change index (RCI). Generalized linear models (GLMs) were used to partition explained deviance in MCK and RCI among sources of uncertainty. Results The 26 different variable sets achieved high values of AUC (area under the receiver operating characteristic curve) and yet introduced substantial variation into maps of current distribution. Differences between maps were even greater when distributions were projected into the future. Some 64-78% of the variation between future maps was attributable to choice of predictor variable set alone. Choice of general climate model and emissions scenario contributed a maximum of 15% variation and their order of importance differed for MCK and RCI. Main conclusions Generalized variable sets produce an unmanageable level of uncertainty in species distribution models which cannot be ignored. The use of sound ecological theory and statistical methods to check predictor variables can reduce this uncertainty, but our knowledge of species may be too limited to make more than arbitrary choices. When all sources of modelling uncertainty are considered together, it is doubtful whether ensemble methods offer an adequate solution. Future studies should explicitly acknowledge uncertainty due to arbitrary choices in the model-building process and develop ways to convey the results to decision-makers. [ABSTRACT FROM AUTHOR]

Aim: With climate change challenging marine biodiversity and resource management, it is crucial to anticipate future latitudinal and depth shifts under contrasting global change scenarios to support policy‐relevant biodiversity impact assessments [e.g., Intergovernmental Panel on Climate Change (IPCC)]. We aim to demonstrate the benefits of complying with the Paris Agreement (United Nations Framework Convention on Climate Change) and limiting environmental changes, by assessing future distributional shifts of 10 commercially important demersal fish species. Location: Northern Atlantic Ocean. Time period: Analyses of distributional shifts compared near present‐day conditions (2000–2017) with two Representative Concentration Pathway (RCP) scenarios of future climate changes (2090–2100): one following the Paris Agreement climate forcing (RCP2.6) and another without stringent mitigation measures (RCP8.5). Major taxa studied: Demersal fish. Methods: We use machine learning distribution models coupled with biologically meaningful predictors to project future latitudinal and depth shifts. Structuring projections with information beyond temperature‐based predictors allowed us to encompass the physiological limitations of species better. Results: Our models highlighted the additional roles of temperature, primary productivity and dissolved oxygen in shaping fish distributions (average relative contribution to the models of 32.12 ± 10.24, 15.6 ± 7.5 and 12.1 ± 6.1%, respectively). We anticipated a generalized trend of poleward shifts in both future scenarios, with aggravated changes in suitable area with RCP8.5 (average area loss with RCP2.6 = 13.3 ± 4.1%; RCP8.5 = 40.9 ± 13.3%). Shifts to deeper waters were also predicted to be of greater magnitude with RCP8.5 (average depth gain = 25.4 ± 21.5 m) than with RCP2.6 (average depth gain = 10.4 ± 7.9 m). Habitat losses were projected mostly in the Mediterranean, Celtic and Irish Seas, the southern areas of the North Sea and along the NE coast of North America. Main conclusions: Inclusion of biologically meaningful predictors beyond temperature in species distribution modelling can improve predictive performances. Limiting future climate changes by complying with the Paris Agreement can translate into reduced distributional shifts, supporting biodiversity conservation and resource management. [ABSTRACT FROM AUTHOR]

Aim: Niche‐based models often ignore spatial variation in the climatic niche of a species across its occupied range and the related variation in the response to changing climate conditions. This assumption may lead to inaccurate predictions of species distribution shifts under climate change. Models have been developed to address this issue, but most of them depend upon prior knowledge on evolutionary lineages, phenotypic traits or ecological processes underlying local adaptation or adaptive plasticity. As such information is often lacking, these models are not frequently used to predict distribution shifts for many species. This limits our ability to explore general patterns of change across species. Innovation: Here, we propose a modelling framework that can be applied across a large sample of species to assess their distribution shifts under future climate while exploring the effect of intraspecific spatial variation in the response to climate conditions. The proposed approach does not require a detailed understanding of the processes underlying such variation. The geographical distribution of a species is split into spatial subsets along the gradient of occupied climate conditions. These subsets are considered as proxies for intraspecific spatial niche variation. Local models are built with each subset and their predictions are assembled across the study area under different dispersal assumptions. Using European butterflies as an example, we show that this approach can be used to explore the uncertainty about predicted distribution shifts arising from intraspecific spatial variation in sensitivity and response to changing climate conditions. Main conclusions: Our modelling approach is not intended to replace advanced modelling methods based on species‐specific knowledge of ecological and evolutionary processes, but it is useful as an exploratory tool to detect species for which detailed information on intraspecific responses to climate conditions is likely to make a difference for prediction of future distribution shifts. [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]

Aim The aim was to assess the sensitivity of butterfly population dynamics to variation in weather conditions across their geographical ranges, relative to sensitivity to density dependence, and determine whether sensitivity is greater towards latitudinal range margins. Location Europe. Time period 1980-2014. Major taxa studied Butterflies. Methods We use long-term (35 years) butterfly monitoring data from > 900 sites, ranging from Finland to Spain, grouping sites into 2° latitudinal bands. For 12 univoltine butterfly species with sufficient data from at least four bands, we construct population growth rate models that include density dependence, temperature and precipitation during distinct life-cycle periods, defined to accommodate regional variation in phenology. We use partial R2 values as indicators of butterfly population dynamics' sensitivity to weather and density dependence, and assess how these vary with latitudinal position within a species' distribution. Results Population growth rates appear uniformly sensitive to density dependence across species' geographical distributions, and sensitivity to density dependence is typically greater than sensitivity to weather. Sensitivity to weather is greatest towards range edges, with symmetry in northern and southern parts of the range. This pattern is not driven by variation in the magnitude of weather variability across the range, topographic heterogeneity, latitudinal range extent or phylogeny. Significant weather variables in population growth rate models appear evenly distributed across the life cycle and across temperature and precipitation, with substantial intraspecific variation across the geographical ranges in the associations between population dynamics and specific weather variables. Main conclusions Range-edge populations appear more sensitive to changes in weather than those nearer the centre of species' distributions, but density dependence does not exhibit this pattern. Precipitation is as important as temperature in driving butterfly population dynamics. Intraspecific variation in the form and strength of sensitivity to weather suggests that there may be important geographical variation in populations' responses to climate change. [ABSTRACT FROM AUTHOR]

Aim To understand how climatic conditions influence the geographical distributions of species and their potential responses to climate change, we investigated the relationships between the thermal tolerances of species and the size and limits of their distributions. We tested two hypotheses for endotherms: the climatic variability hypothesis, which predicts increases in range size with increasing breadth of thermal tolerance, and the climatic extreme hypothesis, which predicts that range limits are related to thermal tolerance limits. Furthermore, we tested whether these relationships differ between temperate and tropical areas. Location Global. Time period Present. Major taxa studied Birds and mammals. Methods We compiled data on thermal tolerances that had been measured in physiological experiments for 453 endothermic species, along with information on geographical ranges and climatic conditions. We applied phylogenetic generalized least square regressions to test for relationships between thermal tolerance and (a) range size or limits and (b) breadth and extremes of the climatic conditions that each species experiences across its distribution. Results We found that range size was not related to the breadth thermal tolerance for endotherms. However, the range limits at high latitudes as well as the minimum temperatures experienced by species were closely related to the physiological cold tolerances of species. These relationships were particularly strong in temperate regions, but these patterns were not found in the tropics. Main conclusions Our results are inconsistent with the predictions of the climatic variability hypothesis, but are in line with the predictions of the climatic extreme hypothesis. Furthermore, the factors determining species distributions do not appear to be the same in tropical and temperate regions. Our study emphasizes the need to combine spatially explicit distribution models with information from physiological experiments in order to capture regional differences and improve predictions of the responses of species to climate change. [ABSTRACT FROM AUTHOR]

Aim The quantification of species range shifts is critical for developing effective plans to conserve biodiversity. There are numerous methods and metrics for quantifying species range shifts, but we currently lack a comprehensive review of existing approaches used in species range shift studies. Location Global. Time period 2013 - 2014. Major taxa studied All taxa. Methods We conducted a quantitative literature review to first identify the methods currently used for defining a species' range over a particular time and then to identify metrics used for measuring changes in species ranges over time. We provide a roadmap for the selection of methods and metrics for measuring species ranges and species range shifts by discussing opportunities, assumptions and constraints of the different approaches. Results Our literature review revealed six main methods for defining species ranges: observational studies, grid-based mapping, convex hull, kriging, species distribution modelling and hybrid methods. These methods are used with three main metric classes to measure species range shifts: changes in range limit, size and the probability of species occurrences or suitability. Most methods for defining species ranges and subsequent range shifts can be applied to different spatial extents and resolutions and taxa. However, only species distribution models (SDMs) and hybrid methods allow for the exploration of the relationship between species occurrence and environmental variables, and only these methods can be used for forecasting species ranges into future environments. Likewise, the inclusion of ecological processes in range shift calculations requires researchers to use hybrid methods or mechanistic models. Main conclusions Our review revealed a high diversity of methods and metrics used to quantify species range shifts. As these methods and metrics underlie many of the conservation strategies proposed for climate change mitigation (e.g., protection of refugia), we urge the conservation community to evaluate underlying approaches for defining species ranges and measuring species range shifts with an equal level of scrutiny as the conservation strategies that these methods and metrics enable. [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 Many studies postulate that physiological tolerance of climatic variables imposes the primary limit on species geographical distributions, that tolerances are constant through time, that climate has warmed and that geographical distributions shift to maintain species in their thermal niches when climate changes. However, recent studies present evidence that is inconsistent with each of these propositions. Here we ask: how strongly did avian species entire geographical distributions (as opposed to their latitudinal extremes) in North America track temperature changes between 1979 and 2010? Location The continental United States (excluding Alaska) and southern Canada. Methods We examined changes from 1979 to 2010 in the geographical distributions, and the realized temperature niches, of 21 species of passerine birds whose entire breeding ranges fall within the area well sampled by the North American Breeding Bird Survey. We related changes in breeding distributions to the concomitant changes in breeding season temperature. Results The median temperature increased within the breeding ranges of most, but not all, species. Temperature on the coolest 2.5% of routes increased significantly for only 8 of 21 species. Most species' distributions shifted geographically, but the most frequent shift was westward, not northward. Most species' realized temperature niches changed detectably through time, mainly as a result of changing temperature (versus geographical shifts). Where shifts in geographical distribution occurred, in most cases they did not result in smaller changes in species realized temperature niche than species would have experienced by not moving at all. There is little suggestion of a lagged response to climate change. Main conclusions We find only slight evidence that the geographical distributions of North American passeriform birds, considered in their entirety (as opposed to their latitudinal extremes), tracked temperature change. Of the factors that have driven recent shifts in the geographical distributions of North American avian species temperature change is probably only a minor one. [ABSTRACT FROM AUTHOR]

Aim Species distribution modelling typically relies completely or partially on climatic variables as predictors, overlooking the fact that these are themselves predictions with associated uncertainties. This is particularly critical when such predictors are interpolated between sparse station data, such as in the tropics. The goal of this study is to provide a new set of satellite-based climatic predictor data and to evaluate its potential to improve modelled species-climate associations and transferability to novel geographical regions. Location Rain forests areas of Central Africa, the Western Ghats of India and South America. Methods We compared models calibrated on the widely usedWorldClim stationinterpolated climatic data with models where either temperature or precipitation data from WorldClim were replaced by data from CRU, MODIS, TRMM and CHIRPS. Each predictor set was used to model 451 plant species distributions. To test for chance associations, we devised a null model with which to compare the accuracy metric obtained for every species. Results Fewer than half of the studied rain forest species distributions matched the climatic pattern better than did random distributions. The inclusion of MODIS temperature and CHIRPS precipitation estimates derived from remote sensing each allowed for a better than random fit for respectively 40% and 22% more species than models calibrated on WorldClim. Furthermore, their inclusion was positively related to a better transferability of models to novel regions. Main conclusions We provide a newly assembled dataset of ecologically meaningful variables derived from MODIS and CHIRPS for download, and provide a basis for choosing among the plethora of available climate datasets.We emphasize the need to consider the method used in the production of climate data when working on a region with sparse meteorological station data. In this context, remote sensing data should be the preferred choice, particularly when model transferability to novel climates or inferences on causality are invoked. [ABSTRACT FROM AUTHOR]

Aim Current interest in forecasting changes to species ranges has resulted in a multitude of approaches to species distribution models ( SDMs). However, most approaches include only a small subset of the available information, and many ignore smaller-scale processes such as growth, fecundity and dispersal. Furthermore, different approaches often produce divergent predictions with no simple method to reconcile them. Here, we present a flexible framework for integrating models at multiple scales using hierarchical Bayesian methods. Location Eastern North America (as an example). Methods Our framework builds a metamodel that is constrained by the results of multiple sub-models and provides probabilistic estimates of species presence. We applied our approach to a simulated dataset to demonstrate the integration of a correlative SDM with a theoretical model. In a second example, we built an integrated model combining the results of a physiological model with presence-absence data for sugar maple ( A cer saccharum), an abundant tree native to eastern North America. Results For both examples, the integrated models successfully included information from all data sources and substantially improved the characterization of uncertainty. For the second example, the integrated model outperformed the source models with respect to uncertainty when modelling the present range of the species. When projecting into the future, the model provided a consensus view of two models that differed substantially in their predictions. Uncertainty was reduced where the models agreed and was greater where they diverged, providing a more realistic view of the state of knowledge than either source model. Main conclusions We conclude by discussing the potential applications of our method and its accessibility to applied ecologists. In ideal cases, our framework can be easily implemented using off-the-shelf software. The framework has wide potential for use in species distribution modelling and can drive better integration of multi-source and multi-scale data into ecological decision-making. [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 Species distribution models (SDMs) are commonly used to determine threats to biodiversity and opportunities under climate change. Despite SDMs being based on the assumption of complete knowledge of the climate space of the modelled species, truncated occurrence datasets (and hence truncated climate spaces) such as national inventories are often employed. This may lead to prediction errors, which have been proposed to stem from: (1) the degree of climate space truncation and/or (2) instability of the modelling algorithms. Our aim was to explore the potential causes of prediction errors in SDMs using truncated training datasets. Location Europe 11° W-32° E, 34°-72° N. Methods SDMs employing commonly used bioclimatic variables were applied to seven forest tree species. We created two model training datasets covering: (1) Germany only (significantly truncated climate space) and (2) Europe (minimally truncated climate space). Differences between the climate space represented by Germany-only and European data were measured on two-dimensional climate spaces obtained through principal component analysis of the bioclimatic variables. Seven SDM algorithms were run, and the stability of the response function and variable selection for each species and model type were analysed. Results The degree of climate space truncation was less important for model performance than the instability of model algorithms and indiscriminate variable selection. The latter led to irrelevant relationships of species occurrence with bioclimatic variables. These instabilities caused pronounced prediction errors. Main conclusions Our results strongly suggest that erroneous model predictions stem from instability and ecological irrelevance of the statistical functions relating the probability of a species' occurrence to bioclimatic variables, compounded by a lack of consistency in variable selection. Models displaying these characteristics showed lower overall performance when trained with truncated datasets. Further, commonly used ensemble approaches do not compensate for the shortfalls of individual models. Detailed model-by-model and species-by-species analysis of response functions and variable importance is recommended. [ABSTRACT FROM AUTHOR]

Aim To disentangle the effects of environmental and geographical processes driving phylogenetic distances among clades of maritime pine ( P inus pinaster). To assess the implications for conservation management of combining molecular information with species distribution models ( SDMs; which predict species distribution based on known occurrence records and on environmental variables). Location Western Mediterranean Basin and European Atlantic coast. Methods We undertook two cluster analyses for eight genetically defined pine clades based on climatic niche and genetic similarities. We assessed niche similarity by means of a principal component analysis and Schoener's D metric. To calculate genetic similarity, we used the unweighted pair group method with arithmetic mean based on Nei's distance using 266 single nucleotide polymorphisms. We then assessed the contribution of environmental and geographical distances to phylogenetic distance by means of Mantel regression with variance partitioning. Finally, we compared the projection obtained from SDMs fitted from the species level ( SDMsp) and composed from the eight clade-level models ( SDMcm). Results Genetically and environmentally defined clusters were identical. Environmental and geographical distances explained 12.6% of the phylogenetic distance variation and, overall, geographical and environmental overlap among clades was low. Large differences were detected between SDMsp and SDMcm (57.75% of disagreement in the areas predicted as suitable). Main conclusions The genetic structure within the maritime pine subspecies complex is primarily a consequence of its demographic history, as seen by the high proportion of unexplained variation in phylogenetic distances. Nevertheless, our results highlight the contribution of local environmental adaptation in shaping the lower-order, phylogeographical distribution patterns and spatial genetic structure of maritime pine: (1) genetically and environmentally defined clusters are consistent, and (2) environment, rather than geography, explained a higher proportion of variation in phylogenetic distance. SDMs, key tools in conservation management, better characterize the fundamental niche of the species when they include molecular information. [ABSTRACT FROM AUTHOR]

Aim Global changes are predicted to have severe consequences for biodiversity; 34 biodiversity hotspots have become international priorities for conservation, with important efforts allocated to their preservation, but the potential effects of global changes on hotspots have so far received relatively little attention. We investigate whether hotspots are quantitatively and qualitatively threatened to the same order of magnitude by the combined effects of global changes. Location Worldwide, in 34 biodiversity hotspots. Methods We quantify (1) the exposure of hotspots to climate change, by estimating the novelty of future climates and the disappearance of extant climates using climate dissimilarity analyses, (2) each hotspot's vulnerability to land modification and degradation by quantifying changes in land-cover variables over the entire habitat, and (3) the future suitability of distribution ranges of '100 of the world's worst invasive alien species', by characterizing the combined effects of climate and land-use changes on the future distribution ranges of these species. Results Our findings show that hotspots may experience an average loss of 31% of their area under analogue climate, with some hotspots more affected than others (e.g. Polynesia- Micronesia). The greatest climate change was projected in low-latitude hotspots. The hotspots were on average suitable for 17% of the considered invasive species. Hotspots that are mainly islands or groups of islands were disproportionally suitable for a high number of invasive species both currently and in the future. We also showed that hotspots will increase their area of pasture in the future. Finally, combining the three threats, we identified the Atlantic forest, Cape Floristic Region and Polynesia- Micronesia as particularly vulnerable to global changes. Main conclusions Given our estimates of hotspot vulnerability to changes, close monitoring is now required to evaluate the biodiversity responses to future changes and to test our projections against observations. [ABSTRACT FROM AUTHOR]

Aim Many predictions of responses to future climate change utilize ecological niche models ( ENMs). We assess the capacity of these models to predict species distributions under conditions that differ from the current environment by testing whether they can predict past distributions of species. Location From 43° S to 31° S in south-eastern Australia (including Tasmania). Methods We studied three dominant tree species of temperate Australian mesic forests, Atherosperma moschatum, Eucalyptus regnans and Nothofagus cunninghamii. Phylogeographic evidence indicates that these species each survived the Last Glacial Maximum ( LGM) in multiple refugia. We modelled the current distribution of each species and projected those models onto LGM climates under six palaeoclimatic scenarios. The support for phylogeographic-based glacial refugia was estimated under each scenario using three different thresholds for inferring species presence/absence. Results The LGM models under scenarios that allowed for a realistic level of rainfall failed to predict survival of the study species in refugia identified from genetic evidence, apart from those in perhumid western Tasmania. Main conclusions Correct prediction of nearly all modern occurrences of the species suggests that this failure of ENMs to predict refugial survival was not methodological. Rather we conclude that the existing realized niches of these species may have changed since the LGM. Such niche changes may have involved the occurrence of non-analogue climates in the LGM and some significant alteration of fundamental niche (for at least E. regnans). Our results emphasize that predictions of future impacts of climate change on biodiversity will benefit from awareness of the limitations of ENMs in predicting the extinction of populations/species. Greater knowledge of how niches have changed through time and how this relates to the characteristics of species is needed to improve the reliability of ENMs. Niche changes in plants may also affect palaeoclimatic estimates based on fossil pollen. [ABSTRACT FROM AUTHOR]

Aim Species distribution models often assume a changing climate (dynamic climate variables) but unchanged land use (static land use variables) to estimate future species distribution shifts. However, scenarios of projected land use change are available to calculate dynamic land use variables. Surprisingly, the importance of using dynamic instead of static land use variables when projecting potential future species distributions under climate change remains largely unexplored. We tested whether the joint inclusion of land use and climate change scenarios altered the projection of future species distribution compared with the classical approach assuming unchanged land use. Location Europe Methods We used land use and climate change scenarios to estimate the future distribution of a butterfly species ( Lycaena dispar) according to different perspectives of projected environmental change: (1) land use change (dynamic land use and static climate variables), (2) climate change (static land use and dynamic climate variables) and (3) global change (dynamic land use and climate variables). As the importance of land use variables is known to depend on the spatial resolution of the models, we built them across a range of resolutions (50 km, 10 km and 5 km) to examine the resolution-dependent relevance of using dynamic instead of static variables. Results For each resolution, the projected distribution changes were unaltered when using dynamic instead of static land use variables in the models. It was mainly due to the low thematic resolution of the land use change scenarios that include only few dynamic variables. Main conclusions Even at fine spatial resolution (5 km), the available land use change scenarios poorly represent habitat suitability for the species. Hence, they may be of limited support to estimate future species distributions. Instead of supporting the assumption of unchanged future land use, our results plea for an improvement of the thematic resolution of land use change scenarios. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Species distribution models (SDMs) based on current species ranges underestimate the potential distribution when projected in time and/or space. A multi-temporal model calibration approach has been suggested as an alternative, and we evaluate this using 13,000 years of data. Location Europe. Methods We used fossil-based records of presence for Picea abies, Abies alba and Fagus sylvatica and six climatic variables for the period 13,000 to 1000 yr bp. To measure the contribution of each 1000-year time step to the total niche of each species (the niche measured by pooling all the data), we employed a principal components analysis (PCA) calibrated with data over the entire range of possible climates. Then we projected both the total niche and the partial niches from single time frames into the PCA space, and tested if the partial niches were more similar to the total niche than random. Using an ensemble forecasting approach, we calibrated SDMs for each time frame and for the pooled database. We projected each model to current climate and evaluated the results against current pollen data. We also projected all models into the future. Results Niche similarity between the partial and the total-SDMs was almost always statistically significant and increased through time. SDMs calibrated from single time frames gave different results when projected to current climate, providing evidence of a change in the species realized niches through time. Moreover, they predicted limited climate suitability when compared with the total-SDMs. The same results were obtained when projected to future climates. Main conclusions The realized climatic niche of species differed for current and future climates when SDMs were calibrated considering different past climates. Building the niche as an ensemble through time represents a way forward to a better understanding of a species' range and its ecology in a changing climate. [ABSTRACT FROM AUTHOR]

Aims I determine the relative importance of temperature and moisture acting alone and in tandem for range contractions and expansions of mammalian species over c. 70 years. Location The contiguous United States west of the eastern border of the Rocky Mountains (103.77° W). Methods Museum records of 67 mammalian species from two time periods (1900-39 and 1970-2009), mean annual temperature and mean annual precipitation are used to model historic and modern distributions. For each era the region outside each species' range in the opposing era is assigned to zones of range limitation: temperature alone is prohibitive, moisture alone is prohibitive, both preclude the species, or both have values that alone are within the species' tolerance range but in combination are outside its climatic niche ('interaction' limitation). The relative importance of each type of limitation is estimated by their intersection with regions of range contraction and expansion. Results Averaged across species, 82 ± 3% (± SE) of the areas of contraction are now occupied by interaction limitation, and 74 ± 5% of areas expanded into were historically occupied by similar zones. In comparison, areas of range shift in which just temperature or moisture acting alone would have excluded the species comprise between only 9 and 17%, and areas in which both factors are limiting are negligible. Expansions into and contractions from regions of interaction limitation occurred more often than expected by chance given the distribution of this type of limitation in the wider study region. Main conclusions Particular combinations of temperature and moisture can interact directly or indirectly to limit species ranges even when these factors alone do not exceed species tolerances. Change in the correlation between of range-limiting factors can have as much effect on species ranges as absolute change in those factors by themselves. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim We play the role of an ice age ecologist (IAE) charged with conserving biodiversity during the climate changes accompanying the last deglaciation. We develop reserve-selection strategies for the IAE and check them against rankings based on modern data. Location Northern and eastern North America. Methods Three reserve-selection strategies are developed. (1) Abiotic: the IAE uses no information about species-climate relationships, instead maximizing the climatic and geographic dispersion of reserves. (2) Species distribution models (SDMs): the IAE uses boosted-regression trees calibrated against pollen data and CCSM3 palaeoclimatic simulations from 21 to 15 ka bp to predict modern taxon distributions, then uses these as input to the Z onation reserve-ranking program. (3) Rank-and-regress: regression models are used to identify climatic predictors of zonation rankings. All strategies are assessed against a Z onation ranking based on modern pollen distributions. Analysis units are ecoregions and grid cells. Results The abiotic strategy has a negative or no correlation between predicted and actual rankings. The SDM-based strategy fares better, with a significantly positive area-corrected correlation ( r= 0.474, P < 0.001) between predicted and actual rankings. Predictive ability drops when grid cells are the analysis unit ( r= 0.217, P = 0.058). Predictive ability for the rank-and-regress strategy is similar to the SDM results. Main conclusions For the IAE, SDMs improve the predictive ability of reserve-selection strategies. However, predictive ability is limited overall, probably due to shifted realized niches during past no-analogue climates, new species interactions as species responded individually to climate change, and other environmental changes not included in the model. Twenty-first-century conservation planning also faces these challenges, and is further complicated by other anthropogenic impacts. The IAE's limited success does not preclude the use of climate scenarios and niche-based SDMs when developing adaptation strategies, but suggests that such tools offer at best only a rough guide to identifying possible areas of future conservation value. [ABSTRACT FROM AUTHOR]

Aim Interacting communities of species are organized into complex networks, and network analysis is reckoned to be a strong tool for describing their architecture. Many species assemblies show strong macroecological patterns, e.g. increasing species richness with decreasing latitude, but whether this latitudinal diversity gradient scales up to entities as complex as networks is unknown. We investigated this using a dataset of 54 community-wide pollination networks and hypothesized that pollination networks would display a latitudinal and altitudinal species richness gradient, increasing specialization towards the tropics, and that network topology would be affected by current climate. Location Global. Methods Each network was organized as a presence/absence matrix, consisting of P plant species, A pollinator species and their links. From these matrices, network parameters were estimated. Additionally, data about geography (latitude, elevation), climate at the network site (temperature, precipitation) and sampling effort (observation days) and extent (study-plot size) were gathered. Analyses were done using simultaneous autoregressive modelling ( SAR). Results Species richness did not vary strongly with either latitude or elevation. However, network modularity decreased significantly with latitude whereas mean number of links per plant species ( Lp) and A/ P ratio peaked at mid-latitude. Above 500 m a.s.l., A/ P ratio decreased and mean number of links per pollinator species ( La) increased with elevation. Lp displayed mid-ambient peaks with temperature and nestedness and modularity displayed linear relationships with precipitation. Main conclusion Pollination networks showed macroecological patterns. No strong latitudinal or altitudinal gradient in species richness was observed. Lp and the A/ P ratio peaked at mid-latitude whereas modularity decreased linearly. Both patterns are suggestive of a more specialized interaction structure towards the tropics. In particular, mean annual precipitation appeared influential on network topology as both nestedness and modularity varied significantly. Importantly, corrected regressions suggest that neither sampling effort nor extent affected the observed patterns. [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 Climate changes are thought to be responsible for the retreat and eventual extinction of subtropical lauroid species that covered much of Europe and North Africa during the Palaeogene and early Neogene; little is known, however, of the spatial and temporal patterns of this demise. Herein we calibrate ecological niche models to assess the climatic requirements of Laurus L. (Lauraceae), an emblematic relic from the Tethyan subtropical flora, subsequently using these models to infer how the range dynamics of Laurus were affected by Plio-Pleistocene climate changes. We also provide predictions of likely range changes resulting from future climatic scenarios. Location The Mediterranean Basin and Macaronesian islands (Canaries, Madeira, Azores). Methods We used a maximum-entropy algorithm (Maxent) to model the relationship between climate and Laurus distribution over time. The models were fitted both to the present and to the middle Pliocene, based on fossil records. We employed climatic reconstructions for the mid-Pliocene (3 Ma), the Last Glacial Maximum (21 ka) and a CO2-doubling future scenario to project putative species distribution in each period. We validated the model projections with Laurus fossil and present occurrences. Results Laurus preferentially occupied warm and moist areas with low seasonality, showing a marked stasis of its climatic niche. Models fitted to Pliocene conditions successfully predicted the current species distribution. Large suitable areas existed during the Pliocene, which were strongly reduced during the Pleistocene, but humid refugia within the Mediterranean Basin and Macaronesian islands enabled long-term persistence. Future climate conditions are likely to re-open areas suitable for colonization north of the current range. Main conclusions The climatic requirements of Laurus remained virtually unchanged over the last 3 Myr. This marked niche conservatism imposed largely deterministic range dynamics driven by climate conditions. This species's relatively high drought tolerance might account for the survival of Laurus in continental Europe throughout the Quaternary whilst other Lauraceae became extinct. Climatic scenarios for the end of this century would favour an expansion of the species's range towards northern latitudes, while severely limiting southern populations due to increased water stress. [ABSTRACT FROM AUTHOR]

Aim There is a debate as to whether biotic interactions exert a dominant role in governing species distributions at macroecological scales. The prevailing idea is that climate is the key limiting factor; thus models that use present-day climate–species range relationships are expected to provide reasonable means to quantify the impacts of climate change on species distributions. However, there is little empirical evidence that biotic interactions would not constrain species distributions at macroecological scales. We examine this idea, for the first time, and provide tests for two null hypotheses: ( H0 1) – biotic interactions do not exert a significant role in explaining current distributions of a particular species of butterfly (clouded Apollo, Parnassius mnemosyne) in Europe; and ( H0 2) – biotic interactions do not exert a significant role in predictions of altered species’ ranges under climate change. Location Europe. Methods Generalized additive modelling (GAM) was used to investigate relationships between species and climate; species and host plants; and species and climate + host plants. Because models are sensitive to the variable selection strategies utilised, four alternative approaches were used: AIC (Akaike's Information Criterion), BIC (Bayesian Information Criterion), BRUTO (Adaptive Backfitting), and CROSS (Cross Selection). Results In spite of the variation in the variables selected with different methods, both hypotheses ( H0 1 and H0 2) were falsified, providing support for the proposition that biotic interactions significantly affect both the explanatory and predictive power of bioclimatic envelope models at macro scales. Main conclusions Our results contradict the widely held view that the effects of biotic interactions on individual species distributions are not discernible at macroecological scales. Results are contingent on the species, type of interaction and methods considered, but they call for more stringent evidence in support of the idea that purely climate-based modelling would be sufficient to quantify the impacts of climate change on species distributions. [ABSTRACT FROM AUTHOR]

Aim The magnitude of predicted range shifts during climate change is likely to be different for species living in mountainous environments compared with those living in flatland environments. The southern edges of ranges in mountain species may not shift northwards during warming as populations instead migrate up available elevational gradients; overall latitudinal range appears therefore to expand. In contrast, flatland species should shift range centroids northwards but not expand or contract their latitudinal range extent. These hypotheses were tested utilizing Late Pleistocene and modern occurrence data. Location North America. Methods The location and elevation of modern and Late Pleistocene species occurrences were collected from data bases for 26 species living in mountain or flatland environments. Regressions of elevation change over latitude, and southern and northern range edges were calculated for each species for modern and fossil data sets. A combination of regressions andanovas were used to test whether flatland species shift range edges and latitudinal extents more than mountain species do. Results Flatland species had significantly larger northward shifts at southern range edges than did mountain-dwelling species from the Late Pleistocene to the present. There was also a significant negative correlation between the amount of change in the latitude of the southern edge of the range and the amount of elevational shifting from the Late Pleistocene to the present. Although significant, only c. 25% of the variance could be explained by this relationship. In addition, there was a weak indication that overall range expansion was less in flatland-dwelling than in mountain-dwelling species. Main conclusions The approach used here was to examine past species’ range responses to warming that occurred after the last ice ages as a means to better predict potential future responses to continued warming. The results confirm predictions of differential southern edge and overall range shifts for species occupying mountain and flatland regions in North America. The findings may be broadly applicable in other regions, thus allowing better modelling of future range and distribution related responses. [ABSTRACT FROM AUTHOR]

Aim To determine the relationship between the distribution of climate, climatic heterogeneity and pteridophyte species richness gradients in Australia, using an approach that does not assume potential relationships are spatially invariant and allows for scale effects (extent of analysis) to be explicitly examined. Location Australia, extending from 10° S to 43° S and 112° E to 153° E. Method Species richness within 50 × 50 km grid cells was determined using point distribution data. Climatic surfaces representing the distribution and availability of water and energy at 1 km and 5 km cell resolutions were obtained. Climate at the 50 km resolution of analysis was represented by their mean and standard deviation in that area. Relationships were assessed using geographically weighted linear regression at a range of spatial bandwidths to investigate scale effects. Results The parameters and the predictive strength of all models varied across space at all extents of analysis. Overall, climatic variables representing water availability were more highly correlated to pteridophyte richness gradients in Australia than those representing energy. Their variance in cells further increased the strength of the relationships in topographically heterogeneous regions. Relationships with water were strong across all extents of analysis, particularly in the tropical and subtropical parts of the continent. Water availability explained less of the variation in richness at higher latitudes. Main conclusions This study brings into question the ability of aspatial and single-extent models, searching for a unified explanation of macro-scaled patterns in gradients of diversity, to adequately represent reality. It showed that, across Australia, there is a positive relationship between pteridophyte species richness and water availability but the strength and nature of the relationship varies spatially with scale in a highly complex manner. The spatial variance, or actual complexity, in these relationships could not have been demonstrated had a traditional aspatial global regression approach been used. Regional scale variation in relationships may be at least as important as more general relationships for a true understanding of the distribution of broad-scale diversity. [ABSTRACT FROM AUTHOR]

Aim Climate is an important determinant of species distributions. We assess different aspects of risk arising from future climate change by quantifying changes in the spatial distribution of future climatic conditions compared with the recent past. Location Europe. Methods A 10′ × 10′ resolution gridded data set of five climate variables was used to calculate expected changes to the area, distance and direction of 1931–60 climatic conditions under the HadCM3 climate model for four future climate scenarios based on different rates of greenhouse gas emissions (SRES scenarios). Three levels of tolerance ranges determined the thresholds for which future conditions are considered analogous to 1931–60 (pre-warming) conditions. Results For many parts of Europe, areas with pre-warming analogous climate conditions will be smaller and further away in the future than they are now. For any location in Europe, areas with pre-warming analogous mean annual temperature conditions will, on average, be reduced between 23.7% (B1 scenario) and 49.7% (A1FI scenario) by 2100 when assuming a medium tolerance range. The mean distance to these areas will, on average, increase between 272 km (B1) and 645 km (A1FI). These changes are more pronounced for temperature than for water availability variables and also for narrow tolerance ranges compared to wide tolerance ranges. Using a combined measure of both temperature and precipitation variables, areas with prewarming analogous conditions are predicted to be in a more northeasterly direction in the future, but there are considerable regional differences within Europe. Main conclusions The results suggest that, for some parts of Europe, the loss of area with any suitable climatic conditions represents the greatest risk to biodiversity, but in other regions the distances that species may have to move to reach suitable climatic conditions may be a greater problem. Quantifying the distance and direction in analyses of change of climatically suitable areas can add additional information for climate change risk assessments. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim To assess whether altitude changes in the distribution of butterflies during the second half of the 20th century are consistent with climate warming scenarios. Location The Czech Republic. Methods Distributional data were taken from a recent butterfly distribution atlas, which maps all Czech butterflies using a grid of 10′ longitude to 6′ latitude, equivalent to about 11.1 × 12 km. Cell altitude was used as an independent variable, and altitudinal ranges of individual species (less migrants, extinct species, recent arrivals and extremely rare species) in 1950–80 vs. 1995–2001 and in 1950–80, 1981–94, 1995–2001 were compared using U -tests and linear regressions. Results Of 117 (U -tests) and 119 (regressions) species, we found significant uphill increases in 15 and 12 species, respectively. The two groups were nested; none (U -test) and one (regression) species showed a significant altitudinal decrease. Binomial tests of frequencies of signs of the U -tests and regression coefficients, including nonsignificant ones, also showed that the increases prevailed. The mean and median of the significant shifts were 60 and 90 m, respectively, and the maximum shift per species was 148 m. The recording effort in individual time periods was not biased with respect to altitude. Main conclusion Altitude shifts in the distribution of Czech butterflies are already detectable on the coarse scales of standard distribution maps. The increasing species do not show any consistent pattern in habitat affiliations, conservation status and mountain vs. nonmountain distribution, which renders climatic explanation as the most likely cause of the distributional shifts. [ABSTRACT FROM AUTHOR]