SYMP 22

Ecological Implications of Endemism Hotspots As Climate Change Refugia

Centers of endemism have long been of interest to biogeographers, evolutionary biologists, and ecologists, and more recently to conservation biologists, who often recognize them as biodiversity hotspots and priorities for protection. The evolutionary and ecological processes responsible for producing concentrations of narrow-range species are complex and may include many interacting aspects of climatic, geologic, and biogeographic history. One classic idea with considerable modern resonance is that centers of endemism are associated with the combination of climatic stability and, in many cases, high topographic relief or other environmental heterogeneity. These factors combine to influence the velocity of climatic change, defined as the speed at which organisms must move to remain in a constant climate. Regions, or sites within regions, with low climate-change velocity are potential climatic refugia, where distinct floras and faunas may both persist and speciate during periods of substantial global or regional climate change. Will hotspots of endemism therefore also be centers of persistence and speciation during 21st-century climate change? This symposium explores the ecology, evolution, and conservation of centers of endemism. Speakers will address whether these centers are consistently associated with a low velocity of climate change and coincide with hypothesized climatic refugia. Speakers also will address questions about the ecology and evolution of narrow-range species. For example, what kinds of species are endemic in high-biodiversity regions? Are they extreme specialists for specific environmental conditions? Have they responded to predictable environments that characterize a stable climate, in terms of substrate, physical and biotic environment, or disturbance regime? Do they have conservative niches? Speakers will consider the relative roles of low extinction rates vs. high speciation rates in endemism hotspots and address the relative composition of neoendemics and paleoendemics in centers of endemism, and the ecological or evolutionary processes that produce variation in this ratio. The overarching goal is to explore whether past climatic refugia with concentrations of narrow-range species will remain stable and retain biodiversity during the present and anticipated future condition of rapid climate change – this will be the focus of our discussion section at the end of the symposium. We anticipate that our symposium and associated publications will stimulate renewed interest in the ecology and conservation of endemism hotspots, at a time when the consequences of climate change are manifest as changes in physical environments and the composition of ecological communities worldwide.