Padrão de distribuição de espécies de formigas (Hymenoptera: Formicidae) e o efeito de variáveis ambientais em um gradiente latitudinal na Amazônia

Abstract

Understanding how the number of species varies along the environment at different scales is a challenge. Nowadays we have a reasonable idea of how the species are distributed specially at small and continental scales, but information at mesoscales are stills scarce. Here we investigated the role of regional variables (temperature, precipitation and vegetation type) and local edaphic factors (soil clay content and slope of terrain) on ants species richness at regional and local scale along a latitudinal gradient of approximately 1,350 km in the central Amazon forest. We collected ants in permanent plots using five litter samples and/or ten pitfall samples. In total, we sampled 139 plots and 1,270 samples. We collected 510 species/morphospecies representing 77 genera and 13 subfamilies. At regional scale, the linear model using annual mean temperature, annual mean precipitation, proportion of soil clay content, terrain slope and vegetation type explained 40% of the variation in species richness for pitfall data and 70% to Winkler data. At local scale, the number of ant species sampled with pitfalls and winkler sacks were not related with the predictors variables investigated. Our results, showed that several environmental variables normally associated with local species assembly process, can also operate in larger scales.