The bat fauna of the Caribbean island of Sint Eustatius consists of five documented species—Monophyllus plethodon, Brachyphylla cavernarum, Artibeus jamaicensis, Ardops nichollsi, and Molossus molossus—and one provisional species—Tadarida brasiliensis. The Insular Single-leaf Bat, M. plethodon, is reported in the scientific literature for the first time from Sint Eustatius based on material presented herein. The bat fauna of the island is considered to be unbalanced because only three species, which are the environmental generalists, are abundant, whereas the more specialized species are rare or absent from the fauna. It is our hypothesis that the unbalanced bat fauna on St. Eustatius is the result of chronic environmental degradation and destruction due primarily to human activity.
Data presented herein provide records of four species of bats new to the fauna of the Antillean island of Saba — Monophyllus plethodon, Ardops nichollsi, Tadarida brasiliensis, and Molossus molossus. Together with three species previously recorded from the island – Brachyphylla cavernarum, Artibeus jamaicensis, and Natalus stramineus – the chiropteran fauna of the island is documented to be composed of seven species. Our analysis of species/area relationships for West Indian bats provides a slope value of z = 0.177 and R2 = 0.76; therefore, the bat fauna of the West Indies has the flattest slope for this relationship of any West Indian group. This relationship is best explained by a propensity for over water dispersal by West Indian bats. We propose to unite the chiropteran faunas of the islands of Anguilla, Antigua, Barbuda, Nevis, Saba, St. Barthélemy, St. Eustatius, St. Kitts, and St. Martin by recognizing them as the Northern Antillean Faunal Area. Given the small size of Saba (12 km2) and the even smaller effective habitat for non-molossid bats (4 km2), conservation concerns are expressed for the future of the fauna and some recommendations are made for its preservation.