Factors affecting assemblage attributes of freshwater Oligochaeta in Neotropical shallow floodplain lakes

Abstract

Cite as: Amo, V.E. et al. Factors affecting assemblage attributes of freshwater Oligochaeta in Neotropical shallow floodplain lakes. Acta Limnologica Brasiliensia, 2017, vol. 29, e114. Abstract: Aim: Identify the effects of sediment composition and water conditions on diversity, richness, evenness, density and composition of freshwater Oligochaeta in shallow floodplain lakes. Methods: We sampled 13 shallow floodplain lakes quarterly during the year 2010 in the Upper Paraná River floodplain. In each lake, four sediment samples were taken from the shore and central regions, three of them were used for biological analysis, and one for granulometric analysis. Concomitantly, temperature, dissolved oxygen, pH, conductivity, alkalinity, turbidity and chlorophyll-a were also measured. Initially, the biological samples were analyzed by a stereoscopic microscope. Oligochaeta individuals were identified under optical microscope at the lowest possible taxonomic level. For data analysis, we quantified density, richness, evenness and diversity index of freshwater Oligochaeta. In order to show differences between the months and the analyzed lakes, in relation to the percentages of coarse and fine organic material, the nonparametric Kruskal Wallis test was used. We also calculated the sediment granulometric diversity using the Shannon-Wienner index, using a simple regression analysis. We correlated assemblage attributes of Oligochaeta with sediment diversity and the assemblage species with the limnological variables using the Spearman correlation. Results: A total of 2,090 individuals were found distributed among 27 species. From the total individuals number, 57% were Pristina americana, followed by Dero (Dero) righii with 13%. Assemblage attributes were not significantly correlated with sediment diversity, and 7 of the 27 species recorded showed significant correlations with at least some of the abiotic variables. Conclusions: We verified that the abiotic variables of the water present greater influence on the attributes of the assemblage of freshwater Oligochaeta, when compared with sediment influences. Although we found low local diversity of this group, the wide range of water conditions offered by lakes culminates with a great species richness considering the whole landscape.

Occurrence of Oligochaeta species (Annelida: Clitellata) in Rivers in the State of São Paulo (Brazil)

“…Many authors carry out research on the diversity and ecology of benthic macroinvertebrates and Oligochaeta in Brazilian Rivers and Lakes (TRIVINHO-STRIXINO; CORREIA; SONODA, 2000;CORBI et al, 2004;MARCHESE, 2005;GORNI, 2007;BEHREND et al, 2012;SALES et al, 2014;SANCHES et al, 2016;AMO et al, 2017;GOMES et al, 2017;TAKEDA et al, 2017;GORNI et al, 2018), Reservoirs (DORNFELD et al, 2006JORCIN;NOGUEIRA, 2008;MOLOZZI et al, 2011;GIROLLI et al, 2018;GIROLLI, 2019;GIROLLI et al, 2020) and conservation areas (GORNI, 2007;SANCHES et al, 2021).…”