Benthic macroinvertebrates in the Paranapanema reservoir cascade (southeast Brazil)

Abstract

In this study, the composition, specific richness and abundance of benthic macroinvertebrates (<250 µm) from sediments of eight reservoirs of the Paranapanema River (southeast Brazil), as well as from the main tributaries (Taquari, Pardo and Tibagi) and the mouth zone into the Paraná River were analyzed. Nineteen points distributed along 700 km were sampled quarterly (8 campaigns) during a two-year period (2000 and 2001). The zoobenthos was characterized by a high species richness, (c.a. 100 taxa), with the predominance of Diptera Chironomidae (c.a. 50 taxa). There was a great spatial variation in the assemblage structure, mainly when compared the lacustrine zones of the reservoirs in relation to the fluvial stretches. The Oligochaeta Narapa bonettoi was dominant in sampling stations with sandy sediments and high water velocity, mainly in the Pardo River and in the upstream and downstream of the Paranapanema river mouth (Paraná River). Branchiura sowerbyi, other numerically important Oligochaeta, was abundant in regions of the upper and middle Paranapanema basin. The mollusk bivalve Corbicula fluminea was widely distributed, occurring in most stations and sampling periods. A certain increment in richness and abundance of taxa occurred in the middle Paranapanema. Lower depth, higher flow and increase in the trophic conditions seem to favor the benthic fauna development in this region. A seasonal variation pattern during the two years of study could not be detected, especially concerning the zoobenthos abundance.Keywords: zoobenthos, spatial distribution, temporal distribution, tropical river. Macroinvertebrados bentônicos dos reservatórios em cascata do rio Paranapanema (sudeste, Brasil) ResumoNeste estudo, foi analisada a composição, riqueza específica e abundância de macroinvertebrados bentônicos de oito reservatórios do rio Paranapanema, assim como nos principais tributários (Taquari, Pardo e Tibagi) e zona de desembocadura no rio Paraná. Dezenove pontos distribuídos ao longo de 700 km foram amostrados trimestralmente (oito campanhas) durante dois anos consecutivos (2000 e 2001). O zoobentos foi caracterizado por uma alta riqueza de espécies (c.a. 100 taxa), com a predominância de Diptera Chironomidae (c.a. 50 taxa). Foi observada uma grande variação espacial na estrutura das assembléias, principalmente quando comparadas às zonas lacustres dos reservató-rios e aos trechos fluviais. O Oligochaeta Narapa bonettoi foi dominante em estações de amostragem com sedimento arenoso e elevada velocidade de correnteza, principalmente no rio Pardo e na montante e jusante da zona de desembocadura do rio Paranapanema no rio Paraná. Branchiura sowerbyi, outro Oligochaeta numericamente importante, foi abundante no trecho superior da bacia. O molusco bivalve Corbicula fluminea mostrou-se amplamente distribuído, ocorrendo na maioria dos locais e períodos amostrados. Uma elevação da riqueza e abundância ocorreu no médio Paranapanema. Menor profundidade, maior fluxo e aumento da trofia parecem favorecer o desenvolvimento d...

Relationship between space distribution of the benthic macroinvertebrates community and trophic state in a Neotropical reservoir (Itupararanga, Brazil)

“…Some researches (Pamplin et al 2006, Carew et al 2007, Jorcin & Nogueira 2008, Buss & Vitorino 2010, Cortelezzi et al 2011, Miserendino et al 2011) have improved the knowledge of the bioindicator potential of the benthic macroinvertebrates. Carew et al (2007) analyzed the response of Chironomidae taxa indicators to pollution, especially in the sediment.…”

Benthic macroinvertebrates of a tropical lake: Lake Caçó, MA, Brazil

“…Both natural and artificial lakes provide a wide spectrum of habitats for aquatic insects, so that they form 10 to 90% of all benthic organisms in these water bodies. Thus, in São José dos Cordeiros Dam, PB, chironomids represented, as a mean, 89% of the benthic macroinvertebrates; Brito-Júnior et al (2005); in Lake Monte Alegre, Ribeirão Preto district, SP, Chironomidae contributed with more than 50% of the whole benthic community (Cleto-Filho and Arcifa, 2006); in Jurumirim reservoir, Paranapanema river basin, this group represented 50% of benthic macroinvertebrates (Jorcin and Nogueira, 2008).…”

“…At the same taxonomic level (genus) in Atlantic Forest lakes in Rio Doce Valley (MG) Marques et al (1999) recorded 33 taxa, and in Jurumirim Reservoir, Parapanema River (SP) Jorcin and Nogueira (2008) reported 48 taxa. Improving sampling frequency and taxonomical analysis resolution can considerably increase the richness, as evidenced in the work of Siqueira et al (2007) which found 71 species/morphospecies in the small Fazzari stream, São Carlos, SP.…”

Using oligochaeta assemblages as an indicator of environmental changes

“…Benthic macroinvertebrates are one of the groups affected by the cascade of reservoirs (Callisto et al, 2005;Jorcin and Nogueira, 2008). The flow regulation and stratification patterns developed in reservoirs frequently impact the biota downstream in four ways (Cortes et al 2002): i) alteration of physical and chemical characteristics associated with the release of water and sediment derived from the hypolimnion, that affect life history and density of macroinvertebrates (Cortes et al 2002); ii) alteration of available food resources to aquatic biota, specially through changes in the particulate organic matter (McAllister et al 2001); iii) creation of unstable environment due to daily changes in water level, increasing invertebrate drift (Hansen and Closs 2007); and iv) reduction of water released downstream, which modify abundance and diversity of benthic fauna (Bunn and Arthington, 2002).…”