Time analysis of a forest fragmentation in a river basin and its possible ecological implications

Abstract

Fragmented landscapes function as forest vegetation islands and suffer changes in their original ecological characteristics. The changes in the forested areas of the Forqueta’s river basin, RS, were analyzed in 1989 and 2008. The methodology is based on land use and cover maps of the forested areas and analysis of landscape metrics, in both years. The results showed the forest regeneration in 79.9% between 1989 and 2008. In this process, the number of forest fragments was reduced in 31.1% with an increase of 120% in the core areas of the fragments. The fragments that have significantly contributed to this increase are those having area with less than 1 ha and those with areas between 1 and 10 ha. There was a reduction in the average distance between the fragments, but the distance is still high (> 100 m) for some species flow. The percentage of the landscape total area, covered by the largest fragment, increased in 1326%. The reorganization of forested areas in the basin is occurring from small fragments, probably due to the regeneration of cropland or pasture. These changes may favor forest core species and the establishing of corridors that increase the matrix permeability as so the gene flow.