Spatiotemporal evaluation of functional responses of ichthyofauna and non-native species to river damming: case studies in Batalha (Upper Paraná basin) and Simplício (Paraíba do Sul basin) reservoirs

Abstract

Among human activities with a potential threat to aquatic biodiversity, dams stand out. This activity has been growing significantly, mainly in basins and rivers with hydroelectric potential in Brazil and can significantly affect fish assemblages, causing the introduction and facilitating the establishment of non-native species, in addition to other taxonomic and functional modifications. Thus, studies that integrate several metrics are recommended for evaluating the influence of human actions on the biota, and among such metrics, ² diversity is an important tool to assess the replacement of species and functional attributes over time. Thus, we will test the following hypotheses: 1) the formation of the Batalha and Simplício reservoirs caused changes in the taxonomic diversity of their respective ichthyofaunas; 2) the formation of the Batalha and Simplício reservoirs caused changes in the functional diversity of their respective ichthyofaunas; and 3) the formation of the Batalha and Simplicio reservoirs caused changes in the population attributes of non-native fish species. For this, we will use an approach of taxonomic indexes and analysis (² diversity, species richness, Shannon-Wiener diversity, Pielou evenness, nMDS, PERMANOVA, PERMIDISP and SIMPER) and functional (² functional diversity, FRic, FEve, FDiv, FDis, FRed and CWM). To test the third hypothesis, the population attributes of numerical abundance, biomass abundance, average standard length, average total mass and relative condition factor will be calculated. All analysis will be conducted in the R environment. It is expected, as a result of this proposal, to generate information on the environmental influences of reservoir formation in addition to traditional diversity indices, to generate information with scientific data on the risks of introduction and establishment of species non-natives and propose new ways of analyzing such influences, which are directly related to the functioning of the ecosystem and not only to the presence and absence of species. Also contribute to scientific development, through publications of scientific articles in international journals of high visibility, collaborating with subsidies for decision-makers and managers of aquatic environments.