Influências ambientais em múltiplas escalas espaciais sobre assembleias aquáticas no Cerrado

Abstract

Data analyses of geodynamic aspects, anthropogenic pressures and physical habitats help to understand aquatic assemblage patterns and to develop strategies for water resources management. The aim of this thesis was to evaluate environmental influences on benthic macroinvertebrates and fish assemblages at multiple spatial scales in two watersheds in the Cerrado Biome: one located above the hydropower reservoir of Nova Ponte (Upper Araguari river basin) and the other located above the hydropower reservoir of Três Marias (Upper São Francisco river basin). The methodological procedures were based on the protocols developed by the United States Environmental Protection Agency (US-EPA) and included: (1) spatially balanced sampling design survey, (2) stream physical habitat assessments, (3) biological assessments, (4) ecological assessment through aggregate analysis of environmental data at multiple scales. We showed through our results that the geodynamic factors, anthropogenic pressures and physical habitat structure influence both benthic macroinvertebrates and fish assemblages. Moreover, an anthropogenic stressor gradient influences the biotic integrity of benthic macroinvertebrate assemblages. It was also noted that the assessment of geodynamic factors and anthropogenic pressures influence sediment dynamics. Because it is an approach of relatively low cost, simple understanding and rapid implementation in the field, the applied methodology can be used as a support for decision makers in rehabilitation projects and habitat restoration in watersheds impacted by hydroelectric projects.