Environmental conditions of a neo-tropical river featuring density, composition and taxa richness of bentic invertebrates - DOI: 10.4025/actascibiolsci.v31i4.4844

Abstract

Anthropic activities cause changes in physical and chemical characteristics in aquatic environments, as well as in the biotic component, and several benthic invertebrates species may indicate these changes. In this paper, we characterized the environmental conditions of different sample points in the 119 River, Campo Mourão, State of Paraná, Brazil. Physical and chemical conditions were analyzed in water, and samples of the river substrate were collected for physical and biological analysis. Density, composition and taxa richness of benthic invertebrates were used to distinguish the sampling points according to environmental changes. Alterations in density, composition and richness were reported at all sampling points and samplings, mainly in sites downstream from areas with anthropic changes. Some characteristic taxa of locals with good water quality were recorded, but in smaller numbers compared with taxa that indicate environmental changes. Because the river crosses the urban area, it suffers continuous anthropic pressure and organism distribution throughout this gradient responds to the changes that occur in each sampling point. Thus, our results suggest that an immediate management plan is necessary to recover the whole river along the urban area