Influência do tamanho de Stepping stones em matrizes de pasto sobre a riqueza e abundância de pequenos mamíferos

Abstract

Fragmentation is one of the major problems for species conservation. The vegetation surrounding a fragment, called a matrix, is very important for the survival of species in a fragmented landscape. The type and quality of a matrix may influence the movement of species, and pasture matrices have been shown to be a hostile environment for a large number of species. However, these matrices have elements of the landscape that may interfere with the movement of species, such as stepping stones. Stepping stones may vary in several attributes, such as size and composition, but the effect of variations on the use of the matrix by small mammals is not yet well understood. In this way, the objective of this study was to test the hypothesis that the diameter or size of a stepping stone is directly related to the richness and abundance of species that use it. To test this hypothesis, five categories (degrees) of stepping stone sizes were created (zero to four) according to the number and spacing of the trees in the patches, varying from the absence of trees (clean pasture), which corresponds to category zero until the adjacent fragment, which corresponds to category four. In addition, the fauna of small mammals was sampled, by means of traps arranged in different degrees of stepping stones, in the pastures and fragments in 6 landscapes sampled. A total effort of 1816 night traps was obtained, with 98 catches of 89 individuals belonging to 12 species of small mammals. The analysis of composition, structure, richness and abundance of the community did not show differences between pastures, stepping stone sizes and forest fragments, thus suggesting that stepping stones can be an important implement for the creation and establishment of management measures in these fragmented areas, such as the reintroduction of old native species, helping to recompose ecosystem services in the landscape.