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Ecological assessment of a southeastern Brazil reservoir
Citation:
Martins, I., B. Sanches, Phil Kaufmann, R. Hughes, G. Santos, J. Molozzi, AND M. Callisto. Ecological assessment of a southeastern Brazil reservoir. Biota Neotropica. Departamento de Biologia Vegetal - Instituto de Biologia, Campinas, Brazil, 15(1):1-10, (2015).
Impact/Purpose:
The manuscript entitled, “Ecological assessment of a southeastern Brazil reservoir” by Isabela Martins, Barbara Sanches, Philip Kaufmann, Robert Hughes, Gilmar Santos, Joseline Molozzi, and Marcos Callisto is intended for submission as an article in the journal Biota Neotropica. This work is a demonstration of the application of the USEPA’s National Aquatic Resource Survey methods to a subtropical hydropower reservoir in Brazil. The researchers adapted the randomized systematic sample site selection design of NARS rivers to the complex shoreline littoral area of a large reservoir, and successfully applied EPA’s National Lakes Assessment field methods to those sites. Their application of this survey approach is a pioneering step that demonstrates that these methods could be used routinely to assess reservoir condition in Brazilian and other South American regions with similar challenges. Except for measures of the proportion of non-native invasive taxa, the researchers found that macrobenthos and fish responded primarily to the general condition of the reservoir, rather than to differences in human disturbances and physical-chemical habitat among sites within the reservoir. The results of the survey itself will aid the growing effort to quantify ecological condition globally.
Description:
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 responds 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.
