ANALYSIS OF SPACE-TIME DYNAMICS OF FOREST FRAGMENTS IN THE ALEGRE RIVER SUBWATERSHED, BRAZIL

Abstract

Knowing the history of forest fragmentation in watersheds helps plan and implement practices based on restoration of degraded forest areas. Structural analysis of forest fragments in the Alegre River subwatershed, State of Espírito Santo, was based on landscape metrics using ArcGIS 10 software with Patch Analyst extension, regarding changes during 1975, 2002, and 2007. Analysis showed an increase of about 7% in the total area of forest cover and emergence of 645 new forest fragments. Numerous patches and a small drainage area resulted in a high perimeter-to-area ratio. Simple geometric shapes predominated in smaller patches (< 1 ha). Larger patches (> 20 ha) were close to each other, with a tendency to decrease proximity metric values. The results show that despite increase in vegetated area, the environmental quality of forest remnants is highly jeopardized.