Variação Espaço-Temporal da Assembléia de Morcegos em uma Floresta Estacional Decidual no Norte de Minas Gerais

Abstract

The aim of this study was to investigate the spatial and temporal variation in abundance, richness, structure and composition of different feeding guilds in a Tropical Dry Forest (TDF) in Northern Minas Gerais, and to determine behavioral changes (foraging time) associated to ecological succession in this area. The study was conducted in 12 areas of four successional stages (pasture, early, intermediate and late stages) in the “Mata Seca” State Park, located in Manga, north of Minas Gerais. The typical vegetation of the Park is tropical dry forest dominated by trees that lose 90-95% of their leaves during the dry season (May to October). Bats were captured from eight samples conducted along two years, using 10 mist nets 12 x 2.5 m per night, totaling 96 sampling nights. A total of 542 individuals from five families and 25 species were captured, and the most abundant were Artibeus planirostris (131 individuals), Desmodus rotundus (113) and Carollia perspicillata (89), corresponding approximately 60% of all individuals. Bat abundance was higher, though not significantly different, in the late (n = 230) than in other successional stages. The absence of statistical significance was probably due to the high capture variation within areas of the same successional stage, thus increasing the data variability, besides the relative proximity between sampling sites. Only the proportion of nectarivores differed between stages, with a higher number of captures in the intermediate stage. Bat abundance was significantly lower in dry than wet seasons, but no difference was observed for species richness. Between guilds, only the omnivores and nectarivores varied significantly along the study period. Regarding the timing of bat activity, there was a trend for higher activity in the first hour of sampling, except for hematophagous bats, which showed the opposite behavior. Overall, this was observed for all successional stages, but some deviations can be observed mainly for frugivorous bats. Our results showed that although the loss of late forests will result in loss of diversity, areas in secondary stages of succession are important habitat for bats in TDFs. Due to the lack of studies and the high rate of deforestation observed in TDFs, more studies are needed to known determine general patterns of bat response to degradation in these areas, as well as their effects on conservation measures