Specific differences in habitat requirement drive responses to habitat loss and disturbance in Atlantic Forest small mammals

Abstract

As deforestation proceeds, habitat is lost in the landscape and the human-created matrix augments. Species that differ in their habitat requirements and tolerance to disturbance should not be equally affected by habitat loss and degradation. Forest dependent species should be more affected by these effects than generalist species that can use more than one habitat type. On the other side, non-native species should benefit from environmental degradation. In this work, we compared the responses of three assemblages of small mammals (forest specialist, generalists and open area dwelling species) along a gradient of forest cover in five landscapes of the Atlantic Forest. We followed the responses of the assemblages in native forests and in non-forested matrices, observing diverse responses in adjacent environments within a forest-matrix system. As was expected, the specialists were the most affected by the loss of native habitat; they decayed considerably in richness and abundance below 35% of habitat in the landscape. Generalist species were not affected by the quantity of habitat in the forest but, conversely, they were positively affected by moderate levels of disturbance in the matrix. Open area species did not colonize the forest irrespective of coverage and they were the dominant assemblage in the disturbed, matrix environment.