Forest fragmentation on the Region of Integration of the Lake Tucuruí, Pará, Brazil

Abstract

The forest fragmentation process leads to severe damages to biodiversity, due to the edge effect that occurs in the fragments. This study aimed to evaluate the forest fragmentation in the Region of Integration of the Lake Tucuruí, Pará state. To map the forest fragments, a supervised classification of images Landsat 8 OLI/TIRS was held. The fragments were divided into six size classes: class 1 (< 10 ha), class 2 ( ≥ 10 and < 50 ha), class 3 ( ≥ 50 and < 100 ha), class 4 ( ≥ 100 and < 500 ha), class 5 ( ≥ 500 and < 1,000 ha) and class 6 ( > 1,000 ha). The Fragstats 4.2 was used to calculate area metrics, density, edge, shape, core area (edge effect simulations: 30 m, 60 m, 90 m, 120 m), proximity and contagion. It was accounted 10,273 landscape fragments, of which the majority (4,446 or 43.28%) belongs to class 1. Although in a larger number, the fragments of smaller classes totalized a small area of remaining forest. The edges total and the edges density did not follow a corresponding standard to the fragments size. The largest fragments have the greatest amount of core area, being less prone to the edge effect, despite of having more irregular shapes. It was determined that the remaining vegetation is with a high level fragmentation and fragments isolation in the landscape. In the Region of Integration of the Lake Tucuruí, Itupiranga is the municipality with a vegetation that contributes the most to the biodiversity conservation, while Nova Ipixuna is the one that demands the most conservation actions.