We assessed the effects of physical habitat structure on benthic macroinvertebrate communities in 3 reservoirs: Serra Azul (SA), Vargem das Flores (VF) and Ibirité (IB). We sampled physical and chemical habitat and benthic macroinvertebrates at 30 systematic sites in each reservoir. In SA, the dominant taxa out of 12 were Melanoides tuberculatus Müller, 1774 (15.2%) and Chaoboridae (63.8%). In VF, the dominant taxa, out of 11 were M. tuberculatus (34.2%) and Oligochaeta (33.6%). In IB, M. tuberculatus (91.2%) and Chaoboridae (6.27%) dominated and we collected only 7 taxa. In SA, benthos were significantly influenced by the deciduous shrub understory and bank angle. In IB and VF, the significant physical habitat variables were: land cover, human influence, and aquatic macrophytes. We conclude that human disturbances reduced terrestrial vegetation cover and riparian and littoral physical habitat structural complexity, leading to worse water quality. Those changes, in turn, reduced the taxonomic richness of the benthic macroinvertebrate communities.
Benthic fauna; habitat integrity; semi-lentic ecosystems; benthic bioindicators
