Ragonha F H, Petsch D K, Alves G H Z, Santana H S, Michelan T S, Takeda A M
Programa de Pós-graduação em Ecologia de Ambientes Aquáticos Continentais - PEA, Universidade Estadual de Maringá - UEM, Maringá, PR, Brazil.
Núcleo de Pesquisas em Limnologia Ictiologia e Aquicultura - NUPELIA, Programa de Pós-graduação em Ecologia de Ambientes Aquáticos Continentais - PEA, Departamento de Biologia - DBI, Universidade Estadual de Maringá - UEM, Maringá, PR, Brazil.
Braz J Biol. 2014 Nov;74(4):861-9. doi: 10.1590/1519-6984.05613. Epub 2014 Nov 1.
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 Paraná River main channel, focusing in Oligochaeta community. We hypothesized that (i) in tributaries, Oligochaeta are richer than the main river (Paraná River) and (ii) dammed tributary (Paranapanema River) is poorly diverse than the others. Samples were conducted in Paranapanema, Baía and Ivinhema tributaries using a modified Petersen grab along three transects (samples conducted inside the tributary, in the mouth of each tributary and inside Paraná River). To analyze (i) the difference between the richness and density among the tributaries and the Paraná 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 Baía 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.
支流可能是河流主河道丰富度的来源，而底栖动物群落是验证这种模式的良好工具。在本研究中，我们旨在描述与巴拉那河主河道相关的三条支流中的底栖无脊椎动物组合，重点关注寡毛纲群落。我们假设：（i）在支流中，寡毛纲的物种丰富度高于主河道（巴拉那河）；（ii）筑坝的支流（巴拉那帕内马河）的多样性低于其他支流。在巴拉那帕内马河、巴伊亚河和伊维内河支流中进行采样，沿着三条样带使用改良的彼得森采泥器（在支流内部、各支流河口以及巴拉那河内部进行采样）。为了分析（i）支流和巴拉那河之间丰富度和密度的差异，以及（ii）每个支流样带对寡毛纲丰富度的影响，我们使用了非参数的克鲁斯卡尔 - 沃利斯检验。通过典范对应分析总结了环境变量以及寡毛纲丰富度和组成的变化。共记录了21种不同的底栖无脊椎动物类群，其中寡毛纲组合的密度最高。在寡毛纲中，博内托纳拉帕蚓是最丰富的物种，其次是埃多凯塔单肠蚓和德斯科莱副南美蚓。在我们的结果中，两个假设均被否定，因为我们未发现支流和主河道之间在丰富度和密度上存在显著差异，且各支流的三条样带之间也未发现差异。然而，受筑坝影响较小的支流，尤其是巴伊亚河，记录到了较高的丰富度。这证实了它们对洪泛平原多样性的重要性，并且寡毛纲物种反映了每个支流内栖息地的独特特征。
