Eight years of monitoring aquatic Oligochaeta from the Baía and Ivinhema Rivers

Abstract

The aim of this study was to analyze the factors that influence spatial and temporal variations of the Oligochaeta assemblage in the Baía and Ivinhema Rivers, located in the Upper Paraná River floodplain (Mato Grosso do Sul State, Brazil). Samples of Oligochaeta were collected between February 2000 and November 2007. A total of 27 Oligochaeta species were identified. A Principal Component Analysis (PCA) of the physical and chemical variables was used to summarize the total variation in the data and to identify major environmental gradients. Detrended Correspondence Analysis (DCA) was conducted to verify possible spatial and temporal gradients in the Oligochaeta species distribution. The highest Oligochaeta species densities and richness values were recorded during limnophases. The intensity and amplitude of the potamophase influenced the density, richness and composition of Oligochaeta since many species were transported by high water current velocities and/or died due to the low oxygen levels that are characteristic of this phase. L. hoffmeisteri, P. descolei and A. pigueti were recorded in the potamophase and in the limnophase and we concluded that they are adapted to different conditions of rivers (lotic and lentic) due to the presence of these species during the entire study period in both rivers. Nevertheless, these species were dominant in the potamophase periods of these rivers as they have body adaptations to survive in these conditions. Keywords: Oligochaeta species, Baía and Ivinhema Rivers, flood pulse intensity and amplitude. Oito anos de monitoramento de Oligochaeta aquáticas nos Rios Baía e IvinhemaResumo O objetivo do estudo foi analisar os fatores que influenciam as variações espaciais e temporais da assembléia de Oligochaeta nos Rios Baía e Ivinhema, localizados na planície de inundação do Alto Rio Paraná. (Estado do Mato Grosso do Sul, Brasil). As amostras de Oligochaeta foram coletadas de fevereiro de 2000 a novembro de 2007. Um total de 27 espécies foi identificado. Análise de Componentes Principais (PCA) das variáveis físicas e químicas foi usada para sumarizar a variação total nos dados e identificar os principais gradientes ambientais. Para verificar possíveis gradientes espaciais e temporais na distribuição das espécies de Oligochaeta foi realizada uma Análise de Correspondência Dendrítica com remoção do efeito de arco (DCA). As maiores densidades e riqueza de espécies de Oligochaeta foram registradas nos períodos de águas baixas. A intensidade e amplitude da potamofase influenciaram a riqueza, densidade e composição de espécies, uma vez que muitas das espécies foram carreadas pela alta velocidade de corrente de água e/ou mortas devido aos baixos níveis de oxigênio que foram característicos dessa fase. L. hoffmeisteri, P. descolei and A. pigueti foram registradas nos períodos de potamofase e limnofase e nós concluímos que são adaptadas a diferentes condições de rios (lótico e lêntico) devido a preseça dessas espécies durante todo período estudado em ambos os rios. Contudo, essas e...

Bidirectional exchanges of benthic invertebrates in a large river–floodplain system (Paraná River, Argentina)

“…In addition, we found an increase in the diversity, abundance, and richness from the main river to the lake, and this result was in accordance with other studies of large rivers, showing an increase in complexity from the main channel to the floodplain waterbodies (Tockner et al, 1998;Garcia and Laville, 2001;Amoros and Bornette, 2002;Arscott et al, 2005;Ezcurra de Drago et al, 2007;Reese and Batzer, 2007;Gallardo et al, 2008;Behrend et al, 2009). Lower species diversity, richness, and density near the bank of the main channel may be explained by low organic matter content and granulometry of the sediments, and by high current velocity that excludes lentic organisms as these are not adapted to maintain their position to prevent accidental loss under high current velocity (Bogatov et al, 1995;Dudgeon, 1995;Takeda et al, 2001;Ezcurra de Drago et al, 2004, 2007.…”

Influence of antifouling paint on freshwater invertebrates (Mytilidae, Chironomidae and Naididae): density, richness and composition

“…), since it is a period when the water from the Paraná River invades the flooding area, which includes the Baía River (Thomaz et al, 2004). During this period, the lowest densities and richness of benthic invertebrates are observed (Rosin and Takeda, 2007;Behrend et al, 2009). However, this time period coincides with one of the higher recruitment periods for L. fortunei (Takeda et al, unpublished data).…”

“…This was also an ideal study site because there is previous knowledge of other aquatic invertebrate taxa in the Baía River (Takeda et al, 1997;Takeda and Fujita, 2004;Behrend et al, 2009). …”

First record of Dero (Aulophorus) bimagnasetus Harman (Oligochaeta) from Brazil and habitat characteristics

“…Another 3 Marcus (1942); Du , 1949a; in Cupari River, in the municipality of Óbidos by Marcus (1942); Du , 1949a; 3) Paraná state, in Baía River, in the municipality of Baytaporã by Behrend et al (2009 ; 6) Minas Gerais state, in São Pedro Stream, in the municipality of Juiz de Fora by Stephan (2007).…”