Artigo Científico

malacofauna repr epresas rio Brasil)
A malacofauna bentônica das represas do médio rio Tietê (São Paulo, Brasil) e uma avaliação ecológica das espécies exóticas invasoras, Melanoides av invasoras, tuberculata (Müller) e Corbicula fluminea (Müller)
Ana L. Suriani; Roberta S. França & Odete Rocha
Programa de Pós Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos. Rodovia Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brasil.
E-mail: [e-mail], [e-mail], [e-mail]
ABSTRACT. Benthic malacofauna of the reservoirs of the Middle River Tietê (São Paulo Brazil) and an malacofauna eservoir oirs River
Paulo, Brazil) species, evaluation inv ecological evaluation of the invading exotic species Melanoides tuberculata (Müller) and Corbicula fluminea
(Müller). This study analyze the composition of species, the density and the spatial and temporal distribution of benthic malacofauna in three reservoirs of the Middle Tietê River. The samplings were carried out in two climatic periods, the rainy season in November 2002 and the dry season in August 2003, showing three portions in each reservoir (upper, middle and lower) and following a sweeping with six sampling points in each transect.
Based on the limnological data the reservoirs of the Middle Tietê River were eutrophied with high concentrations of nutrients (total and dissolved). Eight species of mollusks were registered, six natives and two exotics. Of these, the dominant species was the exotic and invading mollusk Melanoides tuberculata (Müller, 1774), found in all reservoirs. Another exotic specie Corbicula fluminea (Müller, 1774), was current in all the reservoirs in both periods of sampling (except in the Barra Bonita reservoir). In the Barra Bonita reservoir only the two exotic species occurred, while in the Bariri and Ibitinga the native species Aylacostoma tenuilabris (Bernardi, 1856), Biomphalaria glabrata (Say, 1818),