Avaliação da atividade de morcegos (Mammalia: Chiroptera) em habitat urbano e rural no município de Dois Vizinhos, Paraná

Abstract

The process of urbanization contributes significantly to structural changes in the environment, contributing to changes in behavior and distribution of species. In Brazil, approximately a quarter of the mammal species are of the order Chiroptera. Taking into account their environmental importance and the need to understand habitat use in altered landscapes, it was proposed to evaluate the influence of urbanization on Chiroptera activity in rural and urban areas of Dois Vizinhos, Paraná. Thirty sampling points were defined, and at each point the bat activity was evaluated a total of four times on different nights, for a period of 10 minutes each night, totaling 40 minutes of sampling effort per collection point. To determine the activity pattern of the individuals at each sampling point, a Batbox Duet HFD3024 ultrasound detector was used and at the beginning of each sampling we characterized the luminous intensity of the sampling points by means of a MLM-1020 digital luxmeter. A total of 1241 passages were recorded during the sample period. Chiropteran activity differed significantly between points in the urban area. Through linear regression analysis we observed a negative relationship between the points of the rural and urban areas with low light and the light incidence. We believe that the chiropteran activity pattern was conditioned to the present luminosity, since this influence on the presence of insects and potential bat predators. Urbanization can decrease the functional / ecological composition of the Chiroptera communities, as well as the diversity of species, due to the similarity of habitat composition. Thus, we believe that the presence of bats in the urban area occurs mainly by insectivorous species and is due to the fact that this habitat has a large amount and diversity of shelters, as well as the ease of finding food, especially insects. We emphasize the need for further studies that, in addition to activity, characterize the taxonomic and functional diversity of species present in the urban area, which may result in mitigating actions of anthropic impact.