Aerial insectivorous bats species richness and relative activity in a tropical forest and pastures in Oaxaca, Mexico

Aerial insectivorous bats species richness and relative activity in a tropical forest and pastures in Oaxaca, Mexico. We seasonally evaluated species richness and relative activity of aerial insectivorous bats along riparian habitats in a tropical forest and pastures in Oaxaca, southeastern Mexico. We used an AnabatTM SD1, 96 hours of recordings and 1656 effective sound files. We identified 9 species and 4 sonotypes, belonging to 4 families: 2 of Mormoopidae (Pteronotus parnellii and P. davyi), 3 of Emballonuridae (Saccopteryx bilineata, Balantiopteryx io and B. plicata), 5 of Vespertilionidae (Eptesicus furinalis, Lasiurus blosevillii, L. ega and 2 Myotis) and 3 of Molossidae (Molossus rufus, Eumops sp. and 1 sonotype). In both habitats and seasons (dry and wet) we reached over 90% of the estimated richness by an asymptotic accumulation model after three hours of recording. Confidence intervals did not overlap around the estimated richness between abitats. In the forestwe registered 8 species in the dry season and 7 in the wet season. In the pastures in both seasons we registered 13 species. All species present in forests were detected in grasslands, and differences in relative activity did not show statistical significance. The general relative activity in both habitats had the tendency to increase during the dry season. In forests, during the dry season, the general relative activity was correlated positively with mean temperature and negatively with relative humidity. During the dry season, in both habitats, we observed a significant and positive relationship of general relative activity and food availability. Riparian systems and associated vegetation immerse in areas under high anthropogenic pressure seem to be an important resource forthe resilience of aerial insectivorous bats. It is necessary to consider local management of this kind of habitats, because of their potential role as corridors between fragments and continuous forest.