Spatial and temporal distribution of the zoobenthos community during the filling up period of Porto Primavera Reservoir (Paraná River, Brazil)

Abstract

This study is part of the limnological monitoring undertaken by the Energy Company of the State of São Paulo (CESP) during the filling up process of the Porto Primavera Reservoir (Hydroelectric Power Plant Engenheiro Sérgio Motta). This reservoir, located in the high Paraná River between the States of São Paulo and Mato Grosso do Sul, is the fourth largest in the country. The first filling up phase started in December 1998 and the second phase in March 2001. Samples for benthic community and sediment characteristics analysis were quarterly collected between August of 1999 and November 2001 and also in August of 2002 (11 sampling campaigns). Samplings were carried out at 13 stations distributed in the reservoir, and at one point located downstream of the dam. 128 invertebrate taxa were identified, being Mollusca, Annelida, Insecta and Nematoda the dominant groups during almost the whole study period. Insecta was the best represented class (9 different orders), and Diptera contributed with higher number of taxa, 63. The exotic species of bivalve Corbicula fluminea was recorded in all sampling stations showing its great capacity to colonize new habitats in the neotropical region. Noticeable variations in the fauna density were observed, considering both different periods and locations. The maximum density of organisms (mean value of 7812 ind.m , were calculated in the transitional river/reservoir zone during the beginning (August 1999) and in the reservoir central zones in the end (August 2002) of the filling up period, respectively. There was no clear relation between the distribution of the different faunistic groups and the sediment granulometric characteristics. However, the decrease or even total absence of organisms was observed at stations with high organic matter concentration (>40%) in a low degradation state (coarse detritus). This fact may be related to the lack of sediment deposits, which would cause difficulties to the fixation of the benthic fauna. Additionally, in those conditions more reduced chemical conditions are expected in function of the intense decomposition process of the flooded vegetation.

A Influência Da Inundação Na Dinâmica Da Vegetação Da Planície Fluvial Do Alto Rio Paraná Em 2007

“…O controle do desfl orestamento é fundamental para a conservação ecológica, geomorfológica, na produção pesqueira, na qualidade de água e qualidade de vida da população das áreas adjacentes (CAMPOS e SOUZA, 1997;SERAFIM 2003;HAYAKAWA, 2007;JORCIN et al, 2009.…”

Growth of Hydrilla verticillata (L.f.) Royle under controlled conditions

“…The Reservoir of HPP Porto Primavera, (or HPP Engenheiro Sérgio Motta), is located in the Paraná River between the coordinates 53-52°W and 22-22°3 0 0 S. (Jorcin et al, 2009). Nowadays, the reservoir area has 2,040 km 2 with an accumulated water volume of 15.7 billion m 3 , and a total length in the longitudinal axis of 250 km.…”

Macroinvertebrate community succession in the Three-Gorges Reservoir ten years after impoundment

“…Most precipitation in the TGR area occurs in summer, 40%e50% of the annual total; only about 5% happens in winter . The macroinvertebrate environment within reservoir experienced significant changes after impoundment (Hall et al, 1999;Scasso et al, 2001), followed by colonization and succession of organisms (Youngman et al, 1976;Wolfinbarger, 1999;Domingues et al, 2007;Jorcin et al, 2009). Ecologists have studied macroinvertebrate community colonization and secondary succession in newly formed reservoirs (Voshell and Simmons, 1984;Bass, 1992;Ruhí et al, 2010).…”