Padrões de distribuição e composição das comunidades de aves aquáticas em áreas úmidas no estado do Rio de Janeiro

Abstract

Understanding how communities vary in space and time concerning environmental conditions is essential to promote waterbird conservation, either in natural, human-altered áreas, or artificial areas. This work aimed to verify the effects of spatial, temporal, and weather variation on the distribution and composition of waterbird communities in continental wetlands. The community structure of waterbirds differed between artificial, natural, and flood lakes. Richness and abundance increased with increasing lake area and distance from human settlement; however, they decreased with increasing depth and extension of open surroundings. Abundance was also influenced by pH, increasing in sites with less acidic pH, and semi-shaded surroundings and grazing pressure, decreasing the number of individuals with the increase of these two variables. The environmental variables with the greatest contribution to the distribution of guilds were the lake area, pH, semi-shaded surroundings, distance from human settlement, macrophyte, and aquatic vegetation height. On the temporal scale, richness remained relatively stable, however, abundance increased over time. Temporal trends were also identified in species composition and dispersion patterns. Precipitation and temperature did not influence richness, indicating that the high number of resident species contributed to a relatively constant richness over time. However, variation in birds abundance was inversely related to precipitation levels, which also influenced environmental conditions acting on the availability of resources and foraging sites for waterbirds. However, abundance was not influenced by temperature. The results suggest that aspects of community structure, richness, abundance, and guilds, are uncoupled and respond in an independent and shared way to the effects of environmental and anthropic variables in inland lakes. Besides, temporal factors and climate variation have different effects on the communities structure. Therefore, these aspects must be considered in a common framework when analyzing changes in the structure of waterbird communities.