Impactos de uma rodovia sobre a fauna de mamíferos: um estudo de caso no norte do estado do Rio Grande do Sul

Abstract

The roads are necessary and essential ventures to human life, as they allow the displacement of people and products, thus generating social and economic development for remote regions. Despite the benefits offered by highways, their impacts are not irrelevant. Roads can cause changes in animal behavior, modifying movement patterns, habitat fragmentation and population isolation, loss of animals in highway construction, vehicle collision mortality, introduction of exotic species, and disease spread. Therefore, understanding how species move through the landscape, their diversity around the highway, and identifying the relationship between landscape and trampling is critical to assess the real impact of highways on wildlife and to verify which possible ecological characteristics influence the mortality of individuals. In view of this problem presented, the objective of this study was to estimate the impacts of a highway on mammal fauna of medium and large size in the north of the State of Rio Grande do Sul. For this, a part of 36 km of BR153 was monitored by car. The monitoring occurred over six months, in 10 days per month, being two blocks of five days in a row, with a 10-day interval between them. To evaluate the fauna surrounding the BR 153 highway, seven fragments of native forest were selected. For the detection of mammals, photographic traps were used in 14 days per month, two blocks of seven consecutive days, with interval of seven days. Over the six months of work, 58 mammals were registered run over on the BR 153 highway, belonging to nine species. Didelphis albiventris and Dasypus novemcintus were the most abundant species, with 23 and 19 records respectively. In the fragments registered 344 mammals, belonging to 17 species. The most abundant species in the fragments were Nasua nasua with 110 records and Dasypus novemcintus with 99 individuals. The number of species run over, when compared to the number of species recorded in the fragments, reinforces the idea that the road kill occurs directed to some species that do not avoid the highways. Species that probably escape safely when crossing roads are those that are agile due to their locomotive ability. Some species are abundantly run over, but not necessarily have their populations sharply reduced by the impact of roads.