Identifying divergence time and paleoclimate change hotspots for better conservation under future climate change

Predicting species distributions under climate change is essential for biodiversity conservation and ecosystem management. However, the role of species' divergence and paleoclimate dynamics in shaping their present-day ranges and their responses to future warming is often overlooked. To fill this gap, we first applied species distribution models and climatic- niche analysis to characterize the current range size, marginality and sensitivity of 2933 Chinese endemic species, and predict their range change for the 2070s under two emission scenarios. Next, we quantified and compared the proportional shifts in future range size between regions identified as ‘divergence hotspots’ (areas of deep evolutionary lineage splitting) and ‘paleoclimate-change hotspots’ (regions that have experienced intense climatic fluctuations since the Last Glacial Maximum). We found that the historical processes of species shape the current distribution patterns and predict future range changes through multiple direct and indirect pathways. Species in long-stable ‘museum areas’ and climatic refuges are projected to contract further, while those from regions of high-intensity paleoclimate change may actually expand. We reveal the importance of the species historical processes in shaping their distributions and climate adaptation. Identifying divergence and paleoclimate change hotspots will help us better protect species and plan protected areas under future climate change.