Phylogenetic endemism in terrestrial mammals

Abstract

AIM

Phylogenetic endemism (PE) identifies geographic concentrations of evolutionarily isolated and spatially restricted biota. Locations with high PE hold elements of biodiversity with little representation elsewhere and whose loss would impact disproportionately on phylogenetic diversity. We aim to determine the global distribution of PE for the world's mammals and to test hypotheses regarding the role of past and present environment and isolation in creating current patterns of evolutionary and spatial isolation. LOCATION

Global land. METHODS

IUCN range polygons were combined with a mammal supertree to estimate PE and related measures at three resolutions. We tested the relationship between PE and predictors representing current and Last Glacial Maximum (LGM) environment and isolation in a model selection framework, for all terrestrial mammals and separately for bats. RESULTS

We identified 12 centres of mammal PE, with implications for conservation decisions. Endemism of mammal evolutionary diversity peaks predominantly in tropical and Southern Hemisphere island and montane regions. PE was most strongly associated with energy availability, isolation, elevation and low variability of current climate. Post LGM climate stability was a surprisingly weak predictor of PE compared with LGM climate itself. When controlling for current species ranges, PE is more strongly explained by past climate and past isolation. MAIN CONCLUSION

While present conditions better explain species endemism, past climate and isolation are central to explaining PE. Isolation at the LGM was a significantly stronger predictor of PE than current isolation, confirming the key role of persistent barriers, even narrow ones such as Wallace's Line. This global evaluation of PE offers an innovative and effective way to capture and test the evolutionary underpinning of whole-clade biogeography. With improving spatial and phylogenetic information, integrative measures such as PE offer a substantial contribution toward comprehending and conserving evolutionary diversity.