Análise de sensibilidade à borda em dois grupos taxonômicos: borboletas frugívoras e mamíferos

Abstract

Human actions have had a profound impact on terrestrial biomes and increased extinction rates to levels above the natural. Changes in land use as a result of agricultural activities mainly threaten tropical biomes, which suffer most intensely from deforestation. These actions lead to the fragmentation process, which transforms the forest landscape into islands of native habitat surrounded by a heterogeneous matrix for anthropic use. One of the consequences of this process is the edge effect, which makes the environment around the forest different from the interior, and can harm species that do not adapt to changes in the forest and the composition of the matrix. The objective of this study was to evaluate the sensitivity of frugivorous butterflies and small mammals to the fragmentation process and edge effect in fragments of the Atlantic Forest, the proportion of individuals lost in these populations due to changes in the landscape and which type of matrix is more suitable for the permanence of each species, in addition to the use of frugivorous butterflies as bioindicators. For this, data from the collection of groups studied in fragments of the Atlantic Forest in São Luiz do Paraitinga and Alfenas, for frugivorous butterflies, and São Luiz do Paraitinga for small mammals, made available by other researchers was used. To evaluate the species response, was used the Edge Response software, a map classified with vegetation cover and spreadsheets containing the collection points and abundance of species at each point. Edge response is software that analyzes a continuous map of land cover (in this case, the classified image), generates an edge influence map, and computes for each species: the type of response to the edge, the sensitivity to the edge and the impact of fragmentation. The results obtained in the first chapter indicated a preference of the species for the forest edge and matrix. The fragmentation process favored species tolerant to the matrix and the heterogeneity of the landscape, forest species were more affected by changes in their native habitat. The results also indicate that frugivorous butterflies can be useful in studies of landscape fragmentation. In the second chapter, results show that some species of small mammals are more sensitive to fragmentation and have suffered significant losses in the population. Other species, more adapted to these changes, may be favored by forest loss. The composition of the matrix may be decisive for the permanence of the populations in the forest fragments.