Long-term climate stability and global endemism patterns
Earth’s glacial cycles have had marked effects on species distributions, and have likely left important legacies in modern ecological communities. Areas with very stable climates are expected to have high rates of endemism and to contain many specialized, weakly dispersing species. Together, these species can be described as possessing a “stable climate trait syndrome”. Regions containing many such species are particular conservation priorities, having both high value and high vulnerability. Here, I will discuss evidence for such a trait syndrome across a wide range of taxonomic groups and consider the implications for community vulnerability to climate change.
Consistent with theory, regions that have experienced low climate change velocity since the Last Glacial Maximum (21000 years ago) contain most of the world’s many endemic vertebrate species. This broad pattern appears to apply across many regions and for many taxonomic groups. Other aspects of the stable climate trait syndrome are less well-supported, with mixed evidence for an effect of stability on species specialization in interaction networks and limited evidence for an effect on dispersal ability. More work is needed to elucidate the less well-studied aspects of the syndrome and to disentangle their possible interactions. In the next 100 years, climate change is expected to accelerate massively. The expected spatial pattern of future change is broadly correlated with past change, though far from perfectly so. Areas with stable past climates that are expected to become unstable in the near future, including many areas of the southern hemisphere, therefore represent particular conservation concerns.