Species-level correlates of land-use responses and climate-change sensitivity in terrestrial vertebrates.

Land-use and climate change are major pressures on terrestrial biodiversity. Species' extinction risk and responses to human pressures relate to ecological traits and other characteristics in some clades. However, large-scale comparative assessments of the associations between traits and responses to multiple human pressures across multiple clades are needed. We investigated whether a set of ecological characteristics that are commonly measured across terrestrial vertebrates (ecological traits and geographic range area) are associated with species' responses to different land-use types and species' likely sensitivity to climate change. We aimed to test whether generalizable patterns in response to these pressures arise across both pressures and across vertebrate clades, which could inform assessments of the global signature of human pressures on vertebrate biodiversity and guide conservation efforts. At the species level, we investigated associations between land-use responses and ecological characteristics with a space-for-time substitution approach, making use of the PREDICTS database. We investigated associations between ecological characteristics and expected climate-change sensitivity, estimated from properties of species realized climatic niches. Among the characteristics we considered, 3 were consistently associated with strong land-use responses and high climate-change sensitivity across terrestrial vertebrate classes: narrow geographic range, narrow habitat breadth, and specialization on natural habitats (which described whether a species occurs in artificial habitats or not). The associations of other traits with species' land-use responses and climate-change sensitivity often depended on species' class and land-use type, highlighting an important degree of context dependency. In all classes, invertebrate eaters and fruit and nectar eaters tended to be negatively affected in disturbed land-use types, whereas invertebrate-eating and plant- and seed-eating birds were estimated to be more sensitive to climate change, raising concerns about the continuation of ecological processes sustained by these species under global changes. Our results highlight a consistently higher sensitivity of narrowly distributed species and habitat specialists to land-use and climate change, which provides support for capturing such characteristics in large-scale vulnerability assessments.

Correlaciones a nivel de especie de las respuestas al uso de suelo y la susceptibilidad al cambio climático en los vertebrados terrestres Resumen El uso de suelo y el cambio climático tienen una presión importante sobre la biodiversidad terrestre. En algunos clados, el riesgo de extinción de las especies y las respuestas a las presiones humanas se relacionan con los rasgos ecológicos y otras características. Sin embargo, varios clados necesitan evaluaciones comparativas a gran escala de las asociaciones entre los rasgos y las respuestas a las presiones humanas. Investigamos si un conjunto de rasgos ecológicos medidos comúnmente en los vertebrados terrestres (rasgos ecológicos y extensión del área geográfica) está asociado con la respuesta de las especies a los diferentes tipos de uso de suelo y la posible susceptibilidad de la especie al cambio climático. Buscamos comprobar si los patrones generalizables de las respuestas a estas presiones surgen en ambas presiones y en todos los clados de vertebrados, lo que podría guiar las evaluaciones de la huella mundial de presiones humanas sobre la diversidad de vertebrados y los esfuerzos de conservación. Investigamos las asociaciones entre la respuesta al uso de suelo y los rasgos ecológicos a nivel de especie con una estrategia de reemplazo de espacio por tiempo y con información de la base de datos PREDICTS. También investigamos las asociaciones entre los rasgos ecológicos y la susceptibilidad al cambio climático esperada, la cual estimamos a partir de las propiedades de los nichos climáticos de las especies. Entre las características que consideramos, tres estuvieron asociadas de manera regular con respuestas fuertes al uso de suelo y alta susceptibilidad al cambio climático en las diferentes clases de vertebrados: la extensión geográfica limitada, la amplitud reducida de hábitat y la especialización en los hábitats naturales (la cual describe si una especie está presente en un hábitat artificial o no). Las asociaciones de otros rasgos con la respuesta de la especie al uso de suelo y su susceptibilidad al cambio climático con frecuencia dependieron de la clase de la especie y el tipo de uso de suelo, lo que resalta un grado importante de dependencia del contexto. En todas las clases, los frugívoros, nectarívoros y los que comen invertebrados eran propensos a sufrir efectos negativos en los usos de suelo de tipo perturbado, mientras que se estimó que las aves herbívoras, las que se alimentan de semillas y las que se alimentan de invertebrados eran más susceptibles al cambio climático, lo que incrementa la preocupación por la continuación de los procesos ecológicos que viven estas especies bajo los cambios globales. Nuestros resultados resaltan una susceptibilidad al uso de suelo y al cambio climático cada vez mayor en las especies con distribución limitada y las especialistas de hábitat, lo que proporciona un respaldo para la captura de dichas características en las evaluaciones a gran escala de la vulnerabilidad.

Intensive human land uses negatively affect vertebrate functional diversity.

Land-use change is the leading driver of global biodiversity loss thus characterising its impacts on the functional structure of ecological communities is an urgent challenge. Using a database describing vertebrate assemblages in different land uses, we assess how the type and intensity of land use affect the functional diversity of vertebrates globally. We find that human land uses alter local functional structure by driving declines in functional diversity, with the strongest effects in the most disturbed land uses (intensely used urban sites, cropland and pastures), and among amphibians and birds. Both tropical and temperate areas experience important functional losses, which are only partially offset by functional gains. Tropical assemblages are more likely to show decreases in functional diversity that exceed those expected from species loss alone. Our results indicate that land-use change non-randomly reshapes the functional structure of vertebrate assemblages, raising concerns about the continuation of ecological processes sustained by vertebrates.

Effects of rarity form on species' responses to land use.

Anthropogenic land-use change causes substantial changes in local and global biodiversity. Rare and common species can differ in sensitivity to land-use change; rare species are expected to be affected more negatively. Rarity may be defined in terms of geographic range size, population density, or breadth of habitat requirements. How these 3 forms of rarity interact in determining global responses to land use is yet to be assessed. Using global data representing 912 vertebrate species, we tested for differences in responses to land use of species characterized by different types of rarity. Land-use responses were fitted using generalized linear mixed-effects models, allowing responses to vary among groups of species with different forms of rarity. Species considered rare with respect to all 3 forms of rarity showed particularly strong declines in disturbed land uses (>40% of species and 30% of individuals in the most disturbed land uses). In contrast, species common both geographically and numerically and with broad habitat requirements showed strong increases (up to 90% increase in species and 40% in abundance in some land uses). Our results suggest that efforts to understand the vulnerability of species to environmental changes should account for different types of rarity where possible. Our results also have potentially important implications for ecosystem functioning, given that rare species may play unique roles within ecosystems.

Efectos de la Forma de Rareza sobre las Respuestas de las Especies ante el Uso de Suelo Sykes et al. Resumen Los cambios en el uso de suelo ocasionados por el humano causan modificaciones sustanciales en la biodiversidad local y mundial. Las especies raras y comunes pueden tener diferencias en la sensibilidad ante el cambio en el uso de suelo; generalmente se espera que las especcies raras se vean afectadas de manera más negativa. La rareza puede estar definida en términos del tamaño de la extensión geográfica, la densidad poblacional o la gama de requerimientos de hábitat. La manera en que interactúan estas tres formas de rareza para determinar las respuestas mundiales ante el uso de suelo todavía no ha sido evaluada. Buscamos diferencias en las respuestas ante el uso de suelo en especies caracterizadas por diferentes tipos de rareza. Para esto usamos datos mundiales que representaron a 912 especies de vertebrados. Las respuestas ante el uso de suelo fueron ajustadas con modelos lineales y generalizados de efectos mixtos, lo que permitió que las respuestas variaran entre los grupos de especies con diferentes formas de rareza. Las especies consideradas como raras con respecto a las tres formas de rareza mostraron declinaciones particularmente fuertes en los usos de suelos perturbados (>40% de las especies y 30% de los individuos en los usos de suelo más perturbados). Como contraste, las especies comunes tanto geográfica como numéricamente y con requerimientos amplios de hábitat mostraron incrementos sólidos (hasta un 90% de incremento de las especies y 40% en abundancia para algunos usos de suelo). Nuestros resultados sugieren que los esfuerzos para entender la vulnerabilidad de las especies ante los cambios ambientales deberían considerar los diferentes tipos de rareza cuando sea posible. Nuestros resultados también tienen implicaciones potencialmente importantes para el funcionamiento de los ecosistemas, dado que las especies raras pueden tener un papel único dentro del ecosistema.

Impacts of the global food system on terrestrial biodiversity from land use and climate change.

The global food system is a key driver of land-use and climate change which in turn drive biodiversity change. Developing sustainable food systems is therefore critical to reversing biodiversity loss. We use the multi-regional input-output model EXIOBASE to estimate the biodiversity impacts embedded within the global food system in 2011. Using models that capture regional variation in the sensitivity of biodiversity both to land use and climate change, we calculate the land-driven and greenhouse gas-driven footprints of food using two metrics of biodiversity: local species richness and rarity-weighted species richness. We show that the footprint of land area underestimates biodiversity impact in more species-rich regions and that our metric of rarity-weighted richness places a greater emphasis on biodiversity costs in Central and South America. We find that methane emissions are responsible for 70% of the overall greenhouse gas-driven biodiversity footprint and that, in several regions, emissions from a single year's food production are associated with global biodiversity loss equivalent to 2% or more of that region's total land-driven biodiversity loss. The measures we present are relatively simple to calculate and could be incorporated into decision-making and environmental impact assessments by governments and businesses.

Biodiversity conservation: Looking over the horizon.

In an age of planetary changes, conservation efforts are essential to protect biodiversity and nature's benefits to people. Large-scale quantitative analyses forecasting major threats to biodiversity can provide insights into which species and areas should be prioritised for conservation.

Tropical and Mediterranean biodiversity is disproportionately sensitive to land-use and climate change.

Global biodiversity is undergoing rapid declines, driven in large part by changes to land use and climate. Global models help us to understand the consequences of environmental changes for biodiversity, but tend to neglect important geographical variation in the sensitivity of biodiversity to these changes. Here we test whether biodiversity responses to climate change and land-use change differ among biomes (geographical units that have marked differences in environment and species composition). We find the strongest negative responses to both pressures in tropical biomes and in the Mediterranean. A further analysis points towards similar underlying drivers for the sensitivity to each pressure: we find both greater reductions in species richness in the types of land use most disturbed by humans and more negative predicted responses to climate change in areas of lower climatic seasonality, and in areas where a greater proportion of species are near their upper temperature limit. Within the land most modified by humans, reductions in biodiversity were particularly large in regions where humans have come to dominate the land more recently. Our results will help to improve predictions of how biodiversity is likely to change with ongoing climatic and land-use changes, pointing toward particularly large declines in the tropics where much future agricultural expansion is expected to occur. This finding could help to inform the development of the post-2020 biodiversity framework, by highlighting the under-studied regions where biodiversity losses are likely to be greatest.

Climate and land-use change homogenise terrestrial biodiversity, with consequences for ecosystem functioning and human well-being.

Biodiversity continues to decline under the effect of multiple human pressures. We give a brief overview of the main pressures on biodiversity, before focusing on the two that have a predominant effect: land-use and climate change. We discuss how interactions between land-use and climate change in terrestrial systems are likely to have greater impacts than expected when only considering these pressures in isolation. Understanding biodiversity changes is complicated by the fact that such changes are likely to be uneven among different geographic regions and species. We review the evidence for variation in terrestrial biodiversity changes, relating differences among species to key ecological characteristics, and explaining how disproportionate impacts on certain species are leading to a spatial homogenisation of ecological communities. Finally, we explain how the overall losses and homogenisation of biodiversity, and the larger impacts upon certain types of species, are likely to lead to strong negative consequences for the functioning of ecosystems, and consequently for human well-being.