Landscape analysis in a municipality in the arc of deforestation of the Brazilian Amazon rainforest

Abstract

The fight for the conservation of the Amazon region is anything but recent. Despite being one of the highest biodiversity assets in the world, it has undergone intense transformations of the landscape since the beginning of the anthropic “invasion” occupation. Changes in land use and occupation are observed for the municipality of Dom Eliseu, located in the zone characterized as the Arc of Deforestation. Given this premise, we designed this study to provide a quantitative understanding of forest fragmentation in the municipality of Dom Eliseu – PA. For this, cloud-free images from the TM (Landsat 5) and OLI (Landsat 8) sensors for 2008 and 2018 were used, respectively, for supervised classification of land use and land cover to identify the forest areas in the study area. The areas of each fragment were quantified and grouped into size classes, considering as very small (<5 ha), small (5–10 ha), medium (10–100 ha), and large (> 100 ha) fragments. The indexes used were area, edge, density and size, shape, and central. In total, 33,171 forest fragments were found in 2008, reduced to 32,385 in 2018, representing 42.71% of the forest cover area under study. Quantitative characterizations were made with groups of area indexes density and size, shape, and central area, the latter obtained for the distance of 100 m under edge effect. The area mapping infers that the forest fragments in the area are mainly found by very small fragments, smaller than 5 ha, indicating a high degree of forest fragmentation in this landscape during the two years under study.