Efeito do uso do solo sobre o agrupamento trófico funcional da comunidade de macroinvertebrados em riachos na Bacia do Iguaçu

Abstract

Aquatic ecosystems have changed in several scales due to anthropic activities. Thus, this work aims to evaluate the benthic macroinvertebrate community in three different categories of streams classified as urban, rural, and preserved areas, located in Baixo Iguaçu, and analyze biological attributes of such organisms as a tool for assessing water quality. Considering that land use in the studied region is predominantly associated with agricultural and industrial activities, the premise is that the benthic community should reflect water quality in these environments. A total of 28,326 organisms were collected, of which Chironomidae and Oligochaeta were present in all streams. Organisms considered most abundant in streams have the following eating habits: collecting (Chironomidae, Oligochaeta, Nematoda, Baetidae, Crustacea and Caenidae) and predators (Gomphidae, Ceratopogonidae), followed by scraper, collector filter, and, finally, shreders, with less representativeness. The RDA performed with environmental and biological variables explained 47.67% of the variability in the composition and distribution of macroinvertebrates and stream categories. Thus, it can be observed that anthropic activities altered the ecological functions of streams located in an urban area, because in these environments the smallest number of macroinvertebrates was observed, different from preserved streams. The structure and composition of the benthic macroinvertebrate community, proved to be directly related to the physical changes of the environment, showing the occurrence of generalist organisms, which present characteristics of being adaptive to adversities. Finally, it was evidenced that the impacts caused in streams, in urban and rural areas, altered the composition and the functional structure of the assembly of benthic macroinvertebrates.