Nested Distribution Patterns and the Historical Biogeography of the Primates of Guyana

Abstract

I investigated if primate species assemblages exhibit nestedness in Guyana. In a nested pattern, individual species have a strong tendency to be present in all assemblages of equal or greater size than the smallest one in which they occur. I conducted 1,725 km of surveys to determine primate species composition and distribution patterns at sixteen survey sites in Guyana. The resulting dataset showed a strong pattern of nestedness in the distribution of Guyanese primates, and differed significantly from random species assemblages generated using Monte Carlo simulations. Species similarities between sites was significantly but weakly negatively correlated with distance between sites. These assemblage patterns may be due to interspecific variations in the ability of some primate species to cross rivers as well as to species extirpations in western Guyana. The absence of wedge-capped capuchins at four sites, which the model predicted should be occupied by this species, may be due to interspecific competition with brown capuchins.