Variação espaço-temporal do zooplâncton em diferentes ambientes do médio Rio Xingu-PA

• Autor(a) principal: BRITO, Stélio Ângelo da Costa
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFPA
• Texto Completo: http://www.repositorio.ufpa.br:8080/jspui/handle/2011/1707
• topic: CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA::ECOLOGIA DE ECOSSISTEMAS; Zootecnia; Zooplâncton de água doce; Pará - Estado; Rio Xingu - PA

Spatial and temporal variation studies of the zooplankton in the middle Xingu river Brazil, were made for two insular lakes and fluvial environments. The samples were made in a monthly periodicity along one year. The species diversity, the relative and absolute abundance, the biomass, the secudary production and the functional groups were founded. For all the environments studied, one hundred and sixty six species related to three main groups were recorded: one hundred and forty one species of Rotifera; twenty Cladocera species; five species of Copepoda and another group mainly compose of larval stages of insects. In the dry season the Rotifera registered the main density, and during the wet season the low. By the rarefaction curves were detected that the Pimental Lake, and the slow and rapid waters in the main channel show not asymptotic curves for the species diversity. In different sense, the Ilha Grande Lake shows the asymptotic curve for the 12 month with 70 species. For the Boa Esperança and Arroz Cru fluvial environments, the mean total density of zooplankton shows a seasonal variation with the main values for the dry season, especially for the Rotifera group. The dry biomass oscillated between 0,063 a 2,2 g.m-2. In the seasonal variation, the Ilha Grande Lake shows the main biomass variation with range of 0,39 a 1,2 g.m-2 during the wet season and 0,66 g.m-2 during the dry season. A similarity analysis indicated a 35% for all the environments studied in the seasonal variation, with seven similar groups identified. The group G included the Pimental Lake in the wet season as more dissimilar. A SIMPER analysis shows a high mean internal similarity (58%) between the rapid environments during the wet season. The slow river waters with a mean similarity of 48% and, finally lakes with an internal similarity of only 23%. The main dissimilarity was founded for the rapids and lakes environments, during the wet season (70%). A bi-factorial analysis not shows significant differences between the environments studied (ANOSIM r = 0,263; P = 0,2). The Lakes show zooplankton communities statistically different of other environments in the middle Xingu river. The detritivore, filter and omnivore feeding habits predominated in the more abundant forms. In summary, the aquatic environments in the Xingu river, show a pattern of main diversification of Rotifera and Cladocera, which corroborated the founded for another Amazon environments with different types of waters in the Sioli classification. A reduction of the zooplankton viii density related to the wet season, can be associated with the dilution by the waters of the Xingu river, and a perturbation effect in the Lake environments stability.