Efeito da conexão de lagos de várzea com o Rio Solimões sobre a diversidade de peixes

Abstract

The Solimões River is a typical white water river that crosses the Amazon Basin from West to East in the center of the alluvial plain, with a huge amount of lakes in its adjacent floodplain called as “varzea”. The spatial heterogeneity and seasonality are key drivers of the high fish diversity observed in this region. The fish assemblages of thirteen floodplain lakes, located at the middle and low reaches of the Solimões River, were sampled during two years, 2011 and 2012, only the high water season and effect of the connectiotn between these lakes and the Solimões River was evaluated. Samples were collected using chiselsand the images of the lakes were generated by the IRS 6 satellite. Were collected 9321 fish, belonging to 142 species, 27 families and 7 orders. Characiformes was the most abundant group with 84% of the sampled fish, followed by Siluriformes with 12% of the caught fish. The most abundant family was Curimatidae with 33% of the fish. Firstly, the cluster analysis grouped lakes as function of the year, probably due the differences between the flood levels. A second factor represented in the cluster was the distance of connection between lakes and the main river channel. A linear model found that the distance between the lakes and the river channel did not influence richness, diversity and dominance in fish assemblages. At the lakes closer the main river channel was observed a dominance of migratory species as Triportheus spp. and Potamorhinaspp. e Psectrogaster spp. While lakes located far way the main river channel exhibited a dominance of red piraña Pygocentrus natereri. In general, we concluded that fish assemblages of floodplain lakes are structured in accordance with its position in relation to the Solimões River.