Evolutionary History of Amphibians in Biodiversity Hotspots
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. College of Biological Sciences Honors Theses; 2006
Human activities are causing a global extinction event that rivals mass extinctions of the past. To counteract this crisis, conservationists have designated biodiversity hotspots, regions with exceptionally high species diversity that face imminent destruction. Setting aside these hotspots would be especially compelling if they contained not just enormous numbers of species but also excessive evolutionary history (i.e., older-than-typical lineages). A recent study seemed to provide evidence for this extra incentive for hotspot conservation. Sechrest et al. (2002) reported that hotspots contain more evolutionary history than expected based on the numbers of primate and carnivore species they contain. A recent study in our lab contested this claim, particularly for primates. We showed that the original analysis was driven by a single hotspot (Madagascar) that contains an ancient endemic clade. The remaining hotspots will not protect more evolutionary history than expected based on species numbers alone. In fact, for primates, these hotspots contain less evolutionary history than expected. Global conservation initiatives should not be developed under the false impression that hotspots generally contain excessive evolutionary history. In my study, we examined whether hotpots contain more (or less) evolutionary history of amphibians than expected. We used a phylogenetic tree of amphibian families combined with information on species within 34 hotspots. We compared the evolutionary history of species endemic to these hotspots with the amount represented by the same number of species chosen at random from the phylogeny. We found that hotspots do contain significantly more amphibian evolutionary history than expected, and that the vast majority of this extra evolutionary history is contained within just a few hotspots. Our findings provide new support for the global initiative to set aside biodiversity hotspots.
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