Mesoscale spatial ecology of a tropical snake assemblage: the width of riparian corridors in central Amazonia

Large-scale biogeographical determinants of snake assemblages may underestimate the effects of local factors that operate within restricted areas. We determined the influence of ecological gradients on the richness and species composition of snakes in the Reserva Ducke, Manaus, Amazonas, Brazil. Multivariate analyses revealed aspects of habitat selection by snakes which would be impossible to detect with large-scale approaches. There was no evidence for a relationship between the number of species recorded per plot and any of the variables measured. However, the species composition, based on a matrix of Chao dissimilarities between plots, differed significantly between riparian and non-riparian areas. The results have important implications for management and conservation, because Brazilian environmental legislation only provides protection up to 30 m away from streams like those of Reserva Ducke, while snakes use larger riparian areas. If only the areas contemplated by law are protected, the majority of species associated with riparian areas are at risk.