Fine-Grain Data Reveal Vulnerability of Biodiversity to Climate Change.

Quantifying the impacts of ongoing climate change on biodiversity is one of the most pressing scientific challenges. Recent studies have indicated the risk of widespread range contraction and community collapse globally, but their specific interpretation and decision relevance are constrained by the coarse-grain nature of their underlying evidence. Here, using a novel climate change vulnerability metric, we demonstrate for 1804 Western Hemisphere bird species that coarse-grain estimates of climate change vulnerability show limited correspondence with those derived from biologically more relevant fine-grain data. Coarse-grain data used widely in recent assessments miss up to half of the most vulnerable species due to various degrees of underestimation and overestimation that covary with spatial autocorrelation and ecological attributes of species. As a result, the perceived vulnerability of high-biodiversity tropical regions is heavily misrepresented, while temperate regions' vulnerability profiles remain relatively unaffected by this data limitation. For example, species in the Amazon region are even more vulnerable to climate change than previously reported. These findings alter the insights of recent global work and highlight the importance of considering the grain of available evidence. Informed collection of fine-grain data combined with model-based data fusion will be key for effectively assessing and managing the effects of climate change on biodiversity.