Species traits suggest European mammals facing the greatest climate change are also least able to colonize new locations

Aim: The risk climate change poses to biodiversity is often estimated by forecasting the areas that will be climatically suitable for species in the future and measuring the distance of the range shifts species would have to make to reach these areas. Species' traits could indicate their capacity to undergo range shifts. However, it is not clear how range-shift capacity influences risk. We used traits from a recent evidence review to measure the relative potential of species to track changing climatic conditions. Location: Europe. Time period: Baseline period (1961-1990) and forecast period (2035-2064). Major taxa studied: 62 mammal species. Methods: We modelled species distributions using two general circulation models and two representative concentration pathways (RCPs) to calculate three metrics of exposure to climate change: range area gained, range area lost and distance moved by the range margin. We identified traits that could inform species' range-shift capacity (i.e., potential to establish new populations and proliferate, and thus undertake range shifts), from a recent evidence-based framework. The traits represent ecological generalization and reproductive strategy. We ranked species according to each metric of exposure and range-shift capacity, calculating sensitivity to ranking methods, and synthesized both exposure and range-shift capacity into risk syndromes. Results: Many species studied whose survival depends on colonizing new areas were relatively unlikely to undergo range shifts. Under the worst-case scenario, 62% of species studied were relatively highly exposed. 47% were highly exposed and had relatively low range-shift capacity. Only 14% of species faced both low exposure and high range-shift capacity. Both range-shift and exposure metrics had a greater effect on risk assessments than climate models. Main conclusions: The degree to which species' potential ranges will be altered by climate change often does not correspond to species' range-shift capacities. Both exposure and range-shift capacity should be considered when evaluating biodiversity risk from climate change.