Ictiofauna de riachos da Bacia do Rio Araguari, MG: estrutura, composição e relações com aspectos geográficos e amostrais

Abstract

There is a lack of scientific studies on the fish communities of River basin, Araguari. This region is highly impacted, resulting in the loss of the natural characteristics of water bodies, affecting the local fish fauna. Fish assemblages of 38 streams were studied in order to determine the composition and structure of fish fauna, their relationship to land use and occupation and the efficiency of the sampling protocol used. The length of the segment sample was established using the formula: width x 40, and each stream stretch was divided into 10 sections. There were significant differences in species composition among sites impacted and preserved, according to the land use, degree of vegetation cover and human changes. The species accumulation curves were obtained separately for streams and for the sections and showed no stabilization of the observed richness and singletons for the number of sampled streams, and richness and doubletons for the number of sampled sections. The analysis of additive partitioning of diversity indicated a high dissimilarity of species between the streams. To capture 95% of the estimated richness for the study region by Jackknife, it would be necessary samples at 94 streams with length= 40 x width. The results show that the advancement of human activities in the region directly affects the local fish fauna, and environmental heterogeneity would be the factor that best explain the distribution patterns of species.