Partição de recursos em assembleias de primatas neotropicais: uma comparação entre dois tipos vegetacionais da Amazônia

Abstract

Species coexistence is determined in part by the ways species partition resources. Sympatric species use different areas of niche space in several different ways. Primate species are thought to coexist primarily due to differences in daily activity patterns, the use of space, vertical stratification, and diet. The existence of many sympatric primate species in Amazonia suggests that the niche they occupy is partitioned in more than one dimension. In order to examine the mechanisms of coexistence among Neotropical primates, we carried out the first-ever comparison of primate community structure between two areas with the same primate species composition but different vegetation types. We found no evidence for partitioning of habitat use, daily activity patterns, or vertical stratification. All species showed similar daily activity patterns. While species in the REBIO Uatumã assemblage showed preferences for certain forest strata, there was significant overlap in the use of intermediate strata, making vertical stratification an inefficient mechanism for niche separation. We did not detect structural differences between habitats, but we did detect differences in the productivity of habitats and vegetation types during the rainy season. Primates were found to prefer more productive habitats, but only during the rainy season. Habitat preferences are thus driven by habitat productivity, and do not contribute to niche differentiation. Our results suggest no partitioning of the principal niche axes of the primate assemblages we studied. Our hypothesis is that differences in diet during the dry season may be the leading mechanism of resource partitioning among these primates, since food availability is not limiting during the rainy season.