Community structure, vertical stratification and seasonal patterns of Neotropical bats

The complexity of Neotropical bat communities is mainly due to the diverse feeding ecology of the Phyllostomidae, the most speciose family of bats in the Neotropics. These bats are important in pollination and seed dispersal, and are predators of insects and vertebrates. Though temperatures in the tropics do not vary strongly, rainfall is seasonal and geographically variable, and thus influences community dynamics strongly by regulating food and roost availability.;I also investigated the vertical stratification of bats at the community, guild and species level on Barro Colorado Island. Resources among bat species are divided not only by food type, but also foraging habits, including differential use of three-dimensional space. The forest understory showed the least bat activity, whereas bats utilized the canopy most. Many bat species were vertical generalists and occurred throughout all forest levels, whereas some species were preferentially captured within a small vertical range. Community diversity and bat abundance were higher when sub-canopy and canopy forest levels were included, thus changing abundance rank of many species within the community. To adequately sample a Neotropical bat community, all forest strata should be sampled.;Finally, I studied seasonal patterns of abundance for five species in both forests and found three seasonal abundance patterns. Patterns for any one species did not differ significantly between forests and a significant seasonal shift of foraging stratum was not found for any of the studied species. Seasonal movements of bats are of consequence for conservation of bats as well as for the tropical forests upon which they depend.;I examined the community structure and seasonality of species composition and abundance of phyllostomid bats for two Neotropical lowland forests within the rainfall gradient on the Isthmus of Panama: a moist semi-deciduous forest, Barro Colorado Island; and a wet evergreen forest, San Lorenzo. The sites are in close proximity, but vary in vegetation and annual rainfall. The species composition and seasonal occurrence of bats in the two forests were similar, whereas the relative abundance of bats in the wet forest was higher. For several species the differences in relative abundance and rank between forests were considerable, indicating subtle but significant differences between the bat communities.