The influence of local environmental filters on the ichthyofauna of intermittent streams

Abstract

Environmental filters select species favoring their persistence, especially in dynamic environments such as intermittent rivers. The objective of this study was to understand how local environmental filters influence the structure of ichthyofauna in intermittent streams during the wet season, when there is water flow. The ichthyofauna, the habitat characteristics and the physical-chemical parameters of the water were sampled during 2021 and 2022 in four streams of the Acaraú river basin, Ceará state. Among the 17 species collected, Poecilia reticulate Peters, 1859 was the most abundant with 69% of the total individuals. The canonical correspondence analysis showed that variables related to habitat structure, type of substrate, shelter, and mesohabitat were highly correlated with local assemblages, directly influencing the composition and structure of the ichthyofauna. The Sabonete stream presented greater species richness, which was associated with greater habitat heterogeneity, with the substrate varying between mud and stone, and macrophytes as the predominant shelter. The results indicate that habitat characteristics influence species composition in the streams studied, reinforcing the importance of local environmental filters for the selection of fish assemblages in intermittent streams.