A dinâmica na composição da assembleia de peixes em uma vereda: a variação do habitat como fator determinante

Abstract

Fish assemblages respond to biotic and abiotic variations in their habitat, especially to seasonality and spatial heterogeneity, organizing itself in space and time. Physiognomies of Cerrado biome are completely unknown environments under any aspect of their fish fauna, but of great occurrence throughout the biome and main contribution of small-scale water to the medium and large rivers of the interior of the country. This study aimed to describe for temporal and spatial dynamics of an assembly of fish in a vereda system. We test the hypothesis that, because it is a spring environment, the communities would remain stable on a seasonal gradient, with habitat variation within the vereda being the most important factor for occurrence of fish species. We performed seasonal collections over a year in a Vereda inside a reserve, in three physiognomically distinct points. The results showed that the vereda presents a low species richness (seven species), but with most of species being exclusive to the region. The dominant species of the system was the poecilide Phalloceros harpagos, corresponding to more than 90% of the samples. The multivariate analyzes showed that the habitat explained better the variation in the occurrence of the species than the seasonality, and the conductivity and width of the water body were the most important factors. The diversity and pattern found for the studied vereda suggest that veredas may have their own dynamics, different from those described for streams. Thus, it is clear the gap we still have on our knowledge about aquatic systems and we recommend further studies that may help us better understand fish assemblages in trails