Survey of Chimpanzees (Pan troglodytes verus) Outside Protected Areas in Southeastern Senegal

While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered status by the IUCN in 2016 as a result of significant population declines in recent decades, little is known about the population in Senegal. We surveyed the West African chimpanzees outside protected areas in the Kedougou region of southeastern Senegal between November 2014 and July 2015 using recce walks (n = 57, totalling 300 km of pedestrian survey distance) in potential chimpanzee habitats. We recorded direct observations of chimpanzees or indices of chimpanzee activity, such as sleeping nests, footprints and faeces. We accumulated 21 direct contacts with chimpanzees and recorded 3489 chimpanzee nests. We mapped the distribution of chimpanzee sleeping sites and indicators of anthropogenic activity by regional administrative units to facilitate species management and conservation planning in the immediate future. In addition, we identified the habitats and tree species used by chimpanzees to construct their nests in order to explore nesting tree preferences. Chimpanzees used almost 40 tree species in the Kedougou region but 84% of nests were associated with eight tree species, namely Pterocarpus erinaceus, Diospyros mespiliformis, Anogeissus leiocarpus, Hexalobus monopetalus, Cola cordifolia, Lannea sp., Parkia biglobosa and Piliostigma thonningii. Among these eight nesting tree species, 60% of the corresponding nests were located in three species: P. erinaceus, D. mespiliformis and A. leiocarpus. Chimpanzees nested more often in woodland habitat than in gallery forests, although the latter accounts for only a small percentage of available habitat. This study is the most geographically extensive survey of chimpanzees in Senegal to date, broadening our knowledge of the species' northwestern-most distribution in West Africa.