Influência do microhabitat na fauna de mamíferos de médio e grande porte em uma paisagem altamente fragmentada no sul do Brasil

Abstract

The advancement of the activities of our species has been mainly responsible for the modification and / or destruction of natural habitats, due to this fact, it is essential to understand associations between animals and the place where they live in order to understand the dynamics of ecosystems. This study was carried out from July 2018 to June 2019, in six remnants of Atlantic Forest, in the southern high plateau of the state of Rio Grande do Sul, called Upper Uruguay. Seeking to verify associations between mammal fauna, with characteristics that make up the structure of microhabitats and their influence on mastofauna, in a highly fragmented region, the methodology used was to record this fauna and to analyze eight microhabitat variables in 18 distinct points of 100 m², subdivided into four sub-quadrants of 25 m², being three points in each fragment, in six fragments, totaling 18 sample points; The vegetation cover, litter, rock cover, canopy obstruction and vertical vegetation occlusion at three heights variables were measured based on the quadrant method. In addition, the number of trees with PAP greater than 15 cm was measured. The relative frequencies of each species in each fragment were estimated and, to verify the relationships between mammalian species and microhabitat variables, multivariate multiple regression models were developed. As results were registered 412 mammals, divided into six orders, nine families and 14 species. Of all recorded species, five of them had a direct relationship with microhabitat variables: Dasypus novemcinctus showed a positive relationship between the number of records on the percentage of rocks in the soil, attenuating their foraging habits and seeking shelter under or between rocks; Mazama nana, a small deer that revealed to have significantly negative relationships with three variables, rock, litter and soil vegetation, indicating to occupy places with higher vegetative density; The feline Leopardus guttulus has a positive relationship with the vegetation variable in the soil, due to its habits in search of food and camouflage; Leopardus wiedii has been shown to have a negative relationship with the lateral plant obstruction variable of 1.0 to 1.5 m, respectively, and it appears that this feline, even having arboreal skills, supports the terrestrial characteristic, with low vegetation and, finally, Didelphis albiventris according to The analyzes have divergent, negative and positive relationships with the lateral vegetation obstruction variables from 0.50 to 1.0 m, and 1.0 to 1.50 m, respectively, indicating that they prefer to inhabit higher vegetation. In sum, the information generated in this study is indispensable for both understanding the environment of the north of Rio Grande do Sul State and the responses of mastofauna, which may be undergoing changes in habitat selection habits due to various human activities, as well as the triggering of preventive measures in favor of this fauna and the habitats where they live. Finally it is explicit that the variation of the measured conditions is common, which leads to the formation of distinct microhabitats, where exert influences of different magnitude in different species.