Interações entre peixes e plantas em áreas alagáveis amazônicas antropizadas

Abstract

The Amazon basin is the largest and most important tropical hydrographic basin in the world, with the greatest diversity of freshwater fish on the planet. In this region, the flood pulse represents the main driving force responsible for the existence, productivity and interactions of aquatic biota. However, freshwater ecosystems are among the most threatened habitats on Earth, notably with the construction of hydroelectric dams, which are one of the main sources of disturbances for fish assemblages, which can change the food ecology and species composition. In the present study were investigated the composition and trophic structure of the ichthyofauna in the Balbina hydroelectric reservoir, in the Uatumã river downstream and in the pristine environment of the Abacate river, tributary of the Uatumã river, as well as the consumption and potential dispersion of seeds by fish in Uatumã and Abacate rivers, assuming that the regulation of the flood regime of the Uatumã river by the Balbina Dam affects the trophic structure of the ichthyofauna and limits the access of fish to the floodplains forests of the Uatumã river due to the suppression of the flood pulse, resulting in less diversity of fish that consume seeds and seeds in their stomachs in relation to the natural environment of the Abacate river. The results indicated that there was significant difference in the abundance of trophic guilds between the three sampled areas. There was no statistical difference in the species richness of the trophic guilds between the three sampled sites. The greatest diversity of fish that consumed seeds and seeds in their stomachs was recorded for the Uatumã river, demonstrating that the suppression of the flood pulse does not seem to have prevented the access of fish to resources from the floodplains forests of the Uatumã river.