Implicações do mosaico da paisagem na estrutura e composição de espécies de quirópteros no norte do Pantanal

Abstract

The relationship between the chiropterofauna survey and the landscape mosaic was evaluated along the left bank of São Lourenço River (Fazenda Santa Lucia) in the northern Pantanal, MT, Brazil. Samples were collected during 15 nights distributed during the transition period between dry and flooding seasons (end of November to mid-December 2014). A second survey was carried out during the dry season (October 2015). Several vegetational formations were sampled, considering both open (pastures, fields with mounds) and forest areas (cambara and the palm Scheelea phalerata, Arecaceae, as dominant species), totaling 24 sites. Samples were collected by mist nets set at ground level among trails, clearings in the forest, grazing areas and savanna formations (fields with mounds). A total of 27 species within five families were recorded: Emballonuridae (one species), Phyllostomidae (11 genera and 16 species), Noctilionidae (one genus and two species), Molossidae (two genera and three species) and Vespertilionidae (two genera and five species), although species from almost all trophic categories were captured. The richest trophic group was the insectivores with 48% of the species. However, its capture was relatively rare in most study sites. The highest abundance was for the frugivorous trophic guild with 68.9% of the total (454 individuals). The group is widely distributed in the mosaic, may be due to the capture method (mist nets) and to the high representation of the fruit bats subfamily Stenodermatinae in the study region. The Phyllostomidae species, considered sensitive to habitat disturbances, were captured in some of these patches. Four large groups of areas were identified, when composition of species, trophic structure, as well as the foraging strategies were considered. Insectivores were more associated with sparse vegetation areas or open fields, tending to areas closer to water, such as rivers with bridges or artificial tanks (cattle water holes) and seasonally flooded vegetation such as cambara forest. Frugivorous had the highest capture rates in acuri forest, semi-deciduous forest physiognomy with understory dominated by palm trees "acuri" (S. phalerata), indicating shelter availability. Thus, species occurrence seems to be related to trophic habits and foraging strategy, and are primarily distributed according to the vegetation zones of the study region.