Insulae infortunatae: Establishing a Chronology for Late Quaternary Mammal Extinctions in the West Indies

This volume is devoted to recent advances in understanding megafaunal extinctions in the New World during the LQ (for this and all other abbreviations used in this paper, see Table 9.1). A chapter on endemic land-mammal extinctions on the islands comprising the West Indies may therefore seem out of place, because (1) few of the species that once lived on the islands would have qualified as megafaunal, even under a generous definition of that term; and (2) while the WI non-volant mammal fauna eventually suffered near-total collapse, this happened quite recently, long after losses subsided on the mainlands. Yet to ignore the vicissitudes of the WI biota would be to overlook the only non-mainland context in the Western Hemisphere to suffer major LQ extinctions – one that might in principle help us to critically evaluate what we know, or think we know, about cause-effect relationships which forced dramatic losses elsewhere in the New World. For example, because of the proximity of these islands to the adjacent continents, any large-scale climatic changes sufficient to drive extinctions on the mainlands should also have had a determinable and coeval effect in the West Indies. If no appreciable effect can be detected given the data at hand – and, as we shall see, none has been – we need to ask why end-Pleistocene climate change should continue to be considered as the competent mechanism behind New World extinctions. As to the view that human impacts have been the prime movers in causing near-time extinctions, because Homo sapiens has occupied both islands and continents comparatively recently, losses due to direct anthropogenic effects should exhibit comparable features in both theaters. If features are not comparable, or seem to have worked on vastly different time scales, we need to ask why in this case as well. Finally, it is of great biological interest to assess, to the degree possible, how factors of physiology (e.g., body size) or macroecology (e.g., range collapse) that are putatively correlated with mainland extinctions might have affected the island fauna. Although cataloguing losses among Antillean birds and herps (including the often-overlooked chelonians) would also be pertinent to the development of these themes, in my view the story of faunal collapse in the West Indies is best told from the perspective of the group most affected, the mammals (for information on other vertebrate losses, see Pregill, 1981; Pregill and Olson, 1981; http://www.iucnredlist.org).