EFEITOS IMEDIATOS NA COMPOSIÇÃO TAXONÔMICA E FUNCIONAL DE PEIXES EM DECORRÊNCIA DA INSTALAÇÃO DE PEQUENAS CENTRAIS HIDRELÉTRICAS (PCH’s)

Abstract

The installation of small hydroelectric plants (SHPs) will cause changes in the environment and aquatic biota. The objective of this work was to evaluate the immediate effects caused by the implantation of SHPs in the taxonomic and functional composition of fish communities. For this purpose, data were collected from three SHPs (Queixada, Galheiros and Unaí Baixo, in the hydrographic basin of Paranaíba, Tocantins and São Francisco rivers, respectively). The collections were carried out one year before and one after the filling of the SHPs, by means of fishing net of the type meshes. The results showed a significant increase in the taxonomic composition after the implementation of the SHPs, without taxonomic alterations comparing the upstream and downstream regions of the dams. Regarding functional composition, there was no significant temporal or spatial differences. We only verified species increase in existing functional groups, which characterizes functional redundancy. However, although the immediate effects are only identified in taxonomic aspects, studies that evaluate taxonomic effects in the medium and long term are essential, especially in functional groups of more generalist and more specialist species, which may be differently affected.