Conhecer para descomissionar: monitoramento de invertebrados aquáticos na bacia do Rio Pandeiros

Abstract

Hydroelectric dams are among the anthropic impacts that most affect aquatic ecosystems, as they fragment aquatic ecosystems and their drainage basins. The Pandeiros Dam is located in the Pandeiros River basin, currently deactivated. Several studies are being conducted to assess the environmental benefits and risks regarding the potential decommissioning of the dam. Therefore, it is essential that prior monitoring of biotic and abiotic variables is carried out in order to understand the spatial and temporal dynamics of aquatic communities directly affected by the possible decommissioning. In this work, we performed a temporal analysis of the macroinvertebrate community in order to know its natural variability. We collected samples at 8 sampling sites in the dry and rainy periods. We did not find significant differences in the composition, richness and abundance of macroinvertebrates when comparing periods of drought and rain in the same year. However, we observed a marked variation in taxonomic composition, richness and abundance of macroinvertebrates between periods of drought over an interval of 4 years. Despite this difference in the structure and composition of aquatic invertebrates, there were no differences in the physical and chemical parameters of the water. Even at reduced time scales (years), macroinvertebrate communities can have significant variations in their composition and structure. For the future revitalization of the São Francisco River basin, biomonitoring of its waters and tributaries such as the Pandeiros.