Fish community response to environmental variations in an impacted Neotropical basin

Fish communities' organisation is a challenging task due to global, local and temporal variations related to biotic and abiotic factors, highlighting anthropic activities. The Verde River Basin (VRB) was chosen as a model to the fish community study due to its complexity, presenting a longitudinal gradient of degradation. The ichthyofauna and abiotic factors were sampled during twelve months in four sites. Analyses employed rarefaction curves with Hill numbers estimators and canonical correspondence analysis. The endemic Apareiodon sp. (not described), Hypostomus albopunctatus, H.strigaticeps, Oligosarcus paranensis, Neoplecostomus yapo and Trichomycterus diabolus were associated with structurally complex and well-preserved environments. In contrary, Astyanax aff. fasciatus, Corydoras ehrhardti, Geophagus brasiliensis, H.ancistroides and Phalloceros harpagos showed tolerance to impacted environments. The methods here employed allowed to identify and explain differences in the ichthyofauna structure, distinguishing the influence of spatial, temporal and human effects on the fish communities.