Variation in Forest Structure and Composition : the Effect of Habitat Quality on Bornean Orangutan (Pongo pygmaeus morio) Population Density and Nest Features

Abstract

Nest construction is a dialy habitat of independent orangutans. Because nests are reliable indicators of orangutan presence, they have been used commonly to estimate local population density, identify nest site preferences and to determine ranging behavior. Although studies utilizing nests have improved our understanding of some aspects of orangutan ecology, these findings are limited because they do not fully consider variation in forest structure and composition. This study investigated the effect of forest structure and composition on orangutan population density and their nest features. Specifically, we consider different habitat types across several sites in Eastern Borneo including Kutai National Park (Main zona, Rimba Zona, Sangkima, and Preyab) as well as Birawa forest. Data analysis demonstrated that variation of orangutan population densities is influenced not only by habitat quality but also influenced by habitat size. In addition, variation in nest features demonstrate a good correspondence with forest structure and composition.