RESOURCE UTILIZATION AND GUILD STRUCTURE OF SMALL VERTEBRATES IN THE AMAZON FOREST LEAF-LITTER

Ten species of small vertebrates that occurred together in leaf litter of the Amazon tropical rainforest were studied during the dry season in Rondonia, western Brazil. This vertebrate assemblage consisted of t wo diurnal lizards, two diurnal frogs, one nocturnal frog, and five fr og species that are active by day and night. All species feed on small invertebrates, primarily insects and arachnids. There are significant differences in prey types and sizes eaten, and overlap values among s pecies are relatively low. Niche breadths vary from unity (extremely l ow) to high (> 9.0). A pseudocommunity analysis using two different al gorithms indicated that structure exists in the prey resource matrix o f the vertebrate assemblage. The zero structure of the community matri x contributes to the observed structure, i.e. prey items not taken by certain species are important in maintaining structure. Several well-d efined feeding guilds are apparent, and the feeding guilds do not appe ar to follow taxonomic lines.