Tributaries as richness source for Oligochaeta assemblage de um rio Neotropical represado

• Published in: Brazilian journal of biology 2014-11, Vol.74 (4), p.861
• Main Authors: Ragonha, F.H, Petsch, D.K, Alves, G.H.Z, Santana, H.S, Michelan, T.S, Takeda, A.M
• Format: Article
• Language: English
• ISSN: 1519-6984
• DOI: 10.1590/1519-6984.05613

Tributaries may serve as richness source for the river main channel and the zoobenthos community is a good tool to verify this kind of pattern. In this study, we aimed to characterize the benthic invertebrate assemblage in three tributaries associated to the Parana River main channel, focusing in Oligochaeta community. We hypothesized that (i) in tributaries, Oligochaeta are richer than the main river (Parana River) and (ii) dammed tributary (Paranapanema River) is poorly diverse than the others. Samples were conducted in Paranapanema, Baia and Ivinhema tributaries using a modified Petersen grab along three transects (samples conducted inside the tributary, in the mouth of each tributary and inside Parana River). To analyze (i) the difference between the richness and density among the tributaries and the Parana River and (ii) effect of each tributary transect on the Oligochaeta richness we used a nonparametric Kruskal-Wallis test. Changes in environmental variables and in richness and composition of Oligochaeta were summarized by Canonic Correspondence Analysis. It was registered 21 different benthic invertebrates taxa, being Oligochaeta assemblage with the highest density. Within Oligochaeta, Narapa bonettoi was the most abundant species, followed by Haplotaxis aedochaeta and Paranadrilus descolei. In our results we refused both hypotheses, because we did not found significant differences for richness and density between the tributaries and the main river, and also no difference between the three transects of each tributary were found. However, the tributaries less influenced by damming, especially the Baia recorded high richness. This corroborates their importance to diversity in the floodplain and the species of Oligochaeta reflect the peculiar characteristics of habitats within each tributaries. Keywords: Narapa bonettoi, benthic invertebrate, sediments, floodplain, biodiversity. Tributarios podem servir como fonte de riqueza para o canal principal do rio e a comunidade de zoobentos e uma boa ferramenta para verificar esse tipo de padrao. Neste estudo, que teve como objetivo caracterizar as assembleias de invertebrados bentonicos em tres tributarios associados ao canal principal do rio Parana, com foco na comunidade de Oligochaeta. Nossa hipotese e que (i) em afluentes a assembleia de Oligochaeta apresenta maior riqueza do que o rio principal (rio Parana), e (ii) o tributario represado (Rio Paranapanema) e menos diverso do que os demais. As amostras fo