Fishes community composition and patterns of species distribution in Neotropical streams

Abstract

The ichthyofauna of streams in the Neotropical region is not yet fully known. This study aims to investigate the ichthyofauna composition of six streams of the Ijuí River sub-basin, Rio Grande do Sul State, inserted in the Uruguay River basin, as to contribute to the knowledge of fishes species richness and distribution in the south of Brazil. Sampling was carried out between July 2015 and May 2016, bimonthly, using the technique of electric fishing to collect the fishes. Spatial variations (per sampled stream) in the ichthyofauna composition were tested with a permutational multivariate analysis of variance. In total, we collected 5,029 individuals from 55 species, 13 families and five orders. From these species, 17 are endemic to the Uruguay River basin. Five species alone represented approximately 70% of the ichthyofauna abundance sampled. Our hypothesis that the fish community composition is not homogeneous along the streams sampled was confirmed and we observed that species complexity increases from the upstream closest area to the downstream according to the river continuum concept.

Longitudinal and ontogenetic changes in feeding patterns of an insectivorous Crenuchidae in streams of southern Brazil

“…In the Uruguay River Basin, a study was conducted to sample streams in three sections (upper, middle, and lower) of the Ijuí River sub-basin, spanning from upstream to downstream along the longitudinal gradient. This study revealed that the species C. pterostictum ranked among the five most abundant species out of the six sites sampled over the course of one year (Cavalheiro and Fialho 2020). In fact, this species alone accounted for 19 % of all individuals collected in this study and was recognized as one of the dominant species across the three sampled sections of the sub-basin (Cavalheiro and Fialho 2020).…”

“…This study revealed that the species C. pterostictum ranked among the five most abundant species out of the six sites sampled over the course of one year (Cavalheiro and Fialho 2020). In fact, this species alone accounted for 19 % of all individuals collected in this study and was recognized as one of the dominant species across the three sampled sections of the sub-basin (Cavalheiro and Fialho 2020). Dominant species play a crucial role in their respective habitats, exerting a significant influence over the entire community.…”

Composition and distribution of fishes from the Perequê-Açu river basin, Paraty, Rio de Janeiro, Southeastern Brazil

“…Spatial variations on the ichthyofauna distribution among upper, middle, and lower sites of the basin followed Cavalheiro & Fialho (2020), where further explanations on these procedures can be found. Once the abundances of the species were logtransformed, we performed an a priori Permutational Multivariate Analysis of Variance (PERMANOVA), based on the Bray-Curtis dissimilarity index, to identify patterns of distribution of species, which if identified were plotted in a Principal Coordinates Analysis (PCoA) ordination graph, using the Bray-Curtis dissimilarity index (Legendre & Legendre 1998).…”

Ficha de Ancistrus taunayi

“…No Brasil, há registros de Ancistrus taunayi na bacia do rio Uruguai, nos estados de Santa Catarina e Rio Grande do Sul (Fisch-Muller, 2003, Bertaco et al, 2016Cavalheiro & Fialho, 2020).…”