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None of the species of bats occurring in the northern Lesser Antilles is endemic to that region, suggesting considerable dispersal among islands. However, movement patterns of bats in the Lesser Antilles are poorly known and thought to be limited because interisland distances present barriers to dispersal for most species. Genetic data imply restricted dispersal among the islands for the cave-roosting Brachyphylla caoernarum, whereas Artibeus jamaicensis apparently moves among the islands more freely (Carstens et al. 2004). Nevertheless, we do not believe that Antillean bats strike out on their own on a regular basis to move over water from one island to another. It is our conclusion, based on the available data, that stochastic tropical storms and hurricanes moving primarily from southeast to northwest effect dispersal and gene flow for bat populations living in the Lesser Antilles.
Strong hurricanes and volcanic activity are powerful agents of ecological and evolutionary change throughout this archipelago. However, despite the great fluctuations in bat abundance on Montserrat over the last 30 years, none of the species of bats has been extirpated as a result of the dramatic impact of volcanic devastation and a category 5 hurricane. Were these disasters simply insufficient to impact bat biodiversity on Montserrat? Is there a disturbance frequency and severity threshold for bat extirpation, or could it be that we are observing the resilience of a metapopulation in the northern Lesser Antilles?