Assessment of environmental deterioration of habitats associated to amphibians ecosystems of Amazon river basin

Abstract

An assessment of environmental degradation of habitats Varzea, Terra Firme, Igapó and Igarapé was conducted during seventeen years in the Amazon River basin, border between Colombia, Brazil y Peru. Data was collected from 1989 to 2006 in three locations: Matamatá, Atalaia and Javarí. In order to assess the degree of degradation in Varzea and Terra Firme habitats; we calculated percentage of ground cover under five categories: 1. Forest not intervened, 2. Stubble, 3. Chagras, 4. Burned Soils and 5. Bare Soil. In habitats of Igapó and Igarapé were made physiographic descriptions and bathymetric profiles to describe structural degradation of the landscape. Data were processed with SURFER, PAST and BIODIVERSITY software programs. Similarity between samples and years was compared by means of Bray-Curtis index and the statistical covariance was calculated trough a statistical analysis of main components. The Igapó habitat showed a good level of ecological integrity while Varzea and Terra Firme showed spatial habitat fragmentation and a high level of environmental degradation represented in denudation of the land caused by slash and burn practices, mining, grazing and sawmills. For the same reasons, Igarapé habitat, although kept the volume of supply of habitat, over the years showed a progressive deterioration of the landscape