Variação na composição da dieta de duas espécies de caracídeos de pequeno porte como indicadores de impacto ambiental em riachos

Abstract

We evaluated whether the level of creeks degradation alters the diet composition of two characid species, as well as comparing the niche breadth of both between sites. The fish were collected in creeks located in urban areas and in forest remnants during the period from January/2021 to December/2021. During the study, the physical, chemical and microbiological parameters of the water were monitored. In the laboratory, the biometric data of the fish were obtained and the identification of the stomach contents of each fish was carried out. A total of 138 stomachs of Piabina argentea and 104 of Psalidodon fasciatus were analyzed. Only the diet of P.argentea differed significantly between the streams evaluated (F=3.41;P=0.009). Both species presented the same niche breadth in relation to the ingestion of food items, so it was expected that there would be a competition between them, but this did not occur, because even though they shared most of the resources to guarantee their survival, P.argentea explored a greater quantity and diversity of items, while P.fasciatus maintained the same feeding pattern in both locations. In this study, both are good indicators of degraded environments, with P. fasciatus being more sensitive to disturbances and P. argentea being more resilient to environmental changes.