Assessing physical habitat structure and biological condition in eastern Amazonia stream sites

Abstract

The advance of agricultural frontiers and industrialization in Amazonia has increased natural resource deterioration, resulting in degraded physical habitat structure and reduced local aquatic biodiversity. We evaluated the relative sensitivities of the Biological Monitoring Working Party (BMWP) and Average Score Per Taxon (ASPT) biotic indexes based on EPT (Ephemeroptera, Plecoptera, Trichoptera) versus EPT taxa richness, EPT abundance, and Shannon-Wiener EPT diversity for evaluating anthropogenic impacts on Amazonian streams. We expected that EPT-BMWP and EPT-ASPT would be more sensitive in detecting environmental changes on stream biota than the other measures. We sampled 32 stream sites in eastern Amazonia distributed along an environmental gradient resulting from different land use intensities. All the biological metrics except EPT-ASPT were significantly responsive to anthropogenic pressures; however, EPT taxa richness was slightly more responsive.