Composition, microgeographic variation, and sexual dimorphism in Caatingas and Cerrado bat communities from northeast Brazil

Although the South American tropics contains the most diverse chiropteran fauna in the world, most information concerning bats from this region is of a taxonomic or distributional nature. Further, most of our knowledge of Neotropical biology is restricted to locales within mesic predictable biomes. The Brazilian Northeast is an extensive tropical semiarid region characterized by climatic unpredictability and topographic heterogeneity, yet its fauna has never been studied. An 18 month field study of chiropteran populations in Caatingas and Cerrado communities of the Northeast revealed individual, secondary sexual, and microgeographic variation in the bat fauna. Study sites were restricted in size to reduce the probability of sampling bats from different communities while intensive monthly sampling regimes were established to define the faunal composition of each community.