Effects of Urbanization on Stream Ecosystems

The Effects of Urbanization on Biodiversity and Water Quality in the Rio das Velhas Basin, Brazil

Paulo S. Pompeu, Carlos Bernardo M. Alves, and Marcos Callisto

doi: https://doi.org/10.47886/9781888569735.ch2

Abstract.—In Brazil, most urban sewage is discharged without treatment into rivers. This is the situation for the Rio das Velhas, which receives in its upper course the sewage of the state capital of Minas Gerais, Belo Horizonte, with more than 2.4 million inhabitants. Our study focuses on the effects of basin urbanization on aquatic biodiversity and water quality in the Rio das Velhas. We use the assemblage structure and taxonomic composition of fishes and benthic macroinvertebrates as biological indicators of water quality. Effects of Belo Horizonte’s discharge included changes in water quality and declines in fish and benthos richness and diversity. However, the absence of dams in the Rio das Velhas main course, associated with connectivity with the Rio São Francisco system and tributaries in excellent condition, increase its rehabilitation potential.