Zoogeography of West Indian Vertebrates in Relation to Pleistocene Climatic Cycles

Abstract

In the course of our inquiries into the fossil record of late Pleistocene terrestrial vertebrates of the West Indies, we have become impressed by the number of extinctions of species characteristic of arid habitats, savannas, or grasslands. The fossils themselves come mostly from areas now too mesic to support an extensive xerophilic fauna. This observation has led to the supposition that during the last glaciation, the West Indies were drier than they are now, and that those species presently restricted to xeric habitats are probably relicts of this period of aridity. The available data on late Pleistocene climates and sea levels are concordant with the hypothesis that the extinction of a considerable number of vertebrate species was a result of climatic changes since the end of the Pleistocene, 10-12,000 years ago. We find the application of this concept to be of great use in interpreting puzzling patterns of distribution. Because there is a compelling need for a better historical perspective in many ecological models of island biogeography, we have attempted to synthesize the literature on the late Pleistocene fossil record and to relate this to the influence of Pleistocene climatic and sea level changes on vertebrate distributions in the West Indies. In this regard the remarks of Ernest Williams (129) seem especially cogent: Until proper account is taken of the Pleistocene and its consequences, all discussions of island diversity, extinction, and related phenomena in this latest period of geologic time will lack in realism. Evidence that Pleistocene glacial climates significantly altered