AERIAL INSECTIVOROUS BATS IN THE BRAZILIAN PANTANAL: DIVERSITY AND ACTIVITY PATTERNS IN RESPONSE TO HABITAT AND MICROCLIMATE.

In tropical environments, landscape heterogeneity is a key factor determining species richness gradients, while climatic conditions are commonly related to the occurrence and activity patterns of most animal species. We used acoustic monitoring data to test the influence of microclimate variables and habitat on the activity pattern of aerial insectivorous bats in three distinct environments in northern Pantanal, Brazil - Cambarazal, Murundu field and Riparian area. We hypothesized that foraging and feeding activities should be positively related to humidity and temperature; and species composition should differ between habitats. In 30 sampling nights, we obtained 6049 records and identified 16 species and three species complexes distributed in five families. There were no significant differences in species richness between the three habitats, but the riparian area, the most heterogeneous environment sampled, presented the highest levels of foraging and feeding activities. Species composition varied with the sampled habitat, demonstrating that different species use and perceive distinct landscapes in different ways. Only the foraging activity of open-space bats responded to the interaction between relative humidity and different habitat types during the Pantanal's dry season. Our results, obtained exclusively by acoustic sampling, show that many aerial insectivore species and activity patterns are subsampled in studies done exclusively with mist-nets. [ABSTRACT FROM AUTHOR]