Effects of Human Presence on Chimpanzee Nest Location in the Lebialem-Mone Forest Landscape, Southwest Region, Cameroon

Abstract

In several areas of Africa, great apes experience increasing predation pressure as a result of human activities. In this study, terrestrial and arboreal nest construction among chimpanzee (Pan troglodytes ellioti) populations was investigated in the Lebialem-Mone Forest Landscape (LMFL), Southwest Region, Cameroon, to examine the anthropogenic effects on nest location. Data on the height, distribution and approximate age of chimpanzee night nests were collected during two 4-week primate field surveys (July to August 2010; July 2011) at two field sites (Bechati and Andu) within the LMFL. Data were collected using the line transect method. Chimpanzee night nests were categorized by their location: arboreal versus terrestrial. During the two field surveys, arboreal night nests were the most frequently constructed nest type at both sites, and the only type of night nest constructed at Bechati. Terrestrial night nests were also constructed at Andu. The main difference between these two sites is the level of human predation and agricultural development. At Bechati chimpanzees inhabit forest regions around dense, expanding villages and are regularly hunted by humans. However, at Andu the chimpanzee populations are not under the same threat. Therefore, terrestrial night nest construction in the LMFL appears to be a behavior exhibited where there is less human presence.

Ground Night Nesting in Chimpanzees: New Insights from Central Chimpanzees (Pan troglodytes troglodytes) in South-East Cameroon

“…This is further supported in chimpanzees [Baldwin et al, 1981;Pruetz et al, 2008;Last and Muh, 2013] and in bonobos [Fruth and Hohmann, 1994]. We did not investigate humidity in our study, therefore we cannot rule out the possibility that the seasonal effect observed is related to humidity.…”

“…for western lowland gorillas, Gorilla gorilla gorilla , from 7.36% of the time in Petit Loango, Gabon [Furuichi et al, 1997], to 96.2% in La Belgique, Dja Biosphere Reserve, Cameroon . However, bonobos have been observed to ground-nest [Kano, 1983] and chimpanzee ground night nests have increasingly been found to occur in many chimpanzee study sites from east to west [Furuichi and Hashimoto, 2000;Maughan and Stanford, 2001;Koops et al, 2007;Abwe and Morgan, 2008;Pruetz et al, 2008;Hicks, 2010;Last and Muh, 2013], providing evidence of more flexible nesting patterns than previously assumed.…”

“…Predator Release It is commonly accepted that chimpanzee ground nesting becomes possible with predator rarity or absence [Furuichi and Hashimoto, 2000;Maughan and Stanford, 2001;Koops et al, 2007;Pruetz et al, 2008;Last and Muh, 2013], supporting the as- [Samson and Hunt, 2012]. At Assirik, Senegal, the abundance of leopards appeared to cause chimpanzees to nest higher in trees [Baldwin et al, 1981].…”

“…As rainfall is intricately linked to season (season is a categorical measure of rainfall), this may be the factor that leads to the seasonal influence on nesting seen in gorillas in Lopé [Tutin et al, 1995], who built more tree nests as rainfall increased. However, others have refuted this theory, by observing chimpanzee ground nests in the wet season Last and Muh, 2013].…”

“…Chimpanzees may be forced to ground-nest on steep slopes as they are not good terrain for nesting trees [Matsuzawa and Yamakoshi, 1996]; however, Koops et al [2007] found no overall correlation with slope or altitude and occurrence of ground nests. Additionally, other studies have failed to find support that ground nesting results from a lack of suitable nesting trees [Furuichi and Hashimoto, 2000;Koops et al, 2007;Pruetz et al, 2008;Last and Muh, 2013]. In La Belgique swamps, the 5 abundant Uapaca spp.…”