Endangered West African Chimpanzees Pan troglodytes verus (Schwarz, 1934) (Primates: Hominidae) in Senegal prefer Pterocarpus erinaceus, a threatened tree species, to build their nests: implications for their conservation

Abstract

The West African Chimpanzee Pan troglodytes verus is Endangered (A4cd ver 3.1) in Senegal (Humle et al. 2008), mainly due to habitat fragmentation and destruction. We gathered qualitative and quantitative data on the tree species preferences of the West African Chimpanzee for nest building in order to gain insight into habitat dependence. Between March 1998 and Febrary 2000 we identified tree species in which a sample of 1790 chimpanzee nests had been built, and ranked species in preference order. We compared this sample to the relative abundance of tree species in the chimpanzee habitat to determine whether particular species were chosen for nesting. We observed that about a quarter (25.42%) of nests were built in Pterocarpus erinaceus, which is considerably greater than would be expected from the abundance of this species in the habitat (6.35%), indicating a strong preference by chimpanzees. We examined the physical traits of the most-used tree species and concluded that height and wood hardness may be key choice features. P. erinaceus is threatened in Senegal due to extensive cutting, which may endanger chimpanzees living outside the boundaries of protected areas. In the current anthropogenic setting our results provide conservation managers with information on how to protect a key aspect of the chimpanzee natural environment.