Ecological assessment of a southeastern Brazil reservoir

Abstract

Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine how the aquatic biota respond to disturbances. A total of 40 sites in the littoral zone of the reservoir were sampled to characterize physical and chemical habitat, land use, and benthic macroinvertebrate and fish assemblages. The predominant type of land cover near the reservoir was natural vegetation. A total of 29 fish species and 39 macroinvertebrate taxa were collected, including eight alien species. Most sites had intermediate levels of human disturbance, however, high levels of degradation were associated with high proportions of alien species. Disturbances at multiple scales may alter natural patterns and processes, leading to environmental changes and damaging biological communities. Our results reinforce the importance of assessing reservoir ecological conditions at several scales. The study of land use, littoral zone physical habitat characteristics, water quality, and assemblage structure set the ground for proposing actions to rehabilitate and conserve aquatic ecosystems.