Macroinvertebrados bentônicos em rios da Bacia Hidrográfica Teles Pires

Abstract

Aquatic ecosystems have undergone changes at different scales as a negative consequence of anthropic actions. Rivers respond to everything that happens in the areas surrounding the fauna and flora present in the aquatic system, they are also influenced by the physicochemical environment of the body of water, which is why the first step towards understanding how benthic macroinvertebrate communities react to changes in water quality is to analyze which physical and chemical variables are affecting the organisms. Macroinvertebrates are used as biological parameters because they reflect the existing conditions in a prolonged way to the disturbances that occur in the environments. The present study consisted of biomonitoring at the headwaters of the Caiabi, Preto and Renato rivers, belonging to the Teles Pires watershed in the Southern Amazon region, through collections of substrate and water samples, to identify and determine the abundance, richness and diversity of the benthic macroinvertebrates and evaluation of physical-chemical parameters of water. Collections for chemical, physical and biological evaluations were carried out from October 2021 to December 2022, with three collections in the rainy season and three in the dry season, totaling 18 collections. In general, pH values were acidic due to soil characteristics in the region; low values of dissolved oxygen were observed in the Caiabi River, reflecting the characteristics of the source area. A total of 1,213 specimens belonging to the insect taxa (Diptera, Trichoptera, Megaloptera, Odonata, Coleoptera, Plecoptera), phyla Nematoda and Nematomorpha, in addition to the subphylum Crustacea, were collected. The benthic community that presented the greatest diversity is that of the Renato river. The Caiabi River had the highest abundance of diptera, considered a benthic macroinvertebrate associated with impacted environments.