Structure and composition of waterbird community in an wetland in Southern Brazil

Structure and composition of waterbird community in an wetland in Southern Brazil. The water demand rising for rice irrigation claimed the building of barrages. The intervention has changed the original physiognomy incrising the surface area of artificial wetlands and ponds. Month surveys were conduced between May 2005 and August 2007, aiming investigate composition of waterbirds, trophic structure and seasonal variation of waterbird community associated with a pond. Censuses were realized by point counts during intervals of 10 min. Five feeding guilds and 11 foraging functional groups were identified which comprised 36 waterbirds species. Walk insectivores, walk piscivores and flying carnivores were the groups with greater waterbird richness. We verified no significative temporal variation of waterbirds richness and abundance along the study. The waterbirds abundance registered presented positive correlation with water level in the pond. The greater abundances were recorded in Spring and Summer, influenced by Bubulcus ibis, Ardea alba, Jacana jacana and Chrysomus ruficapillus abundances. The variation of water level of the pond determines the availability of habitats and changes the composition of waterbirds throughout the year.