Organization: Primate Habituation Project, Dzanga-Sangha Projecto
Location: Bai Hohou, Dzanga-Ndoki National Park, Central African Republic
Research: Factors Affecting Habitat Use in Western Gorillas at Bai Hokou, Central African Republic
Species/Topic: Western Gorillas (Gorilla gorilla gorilla)
This project aims to describe patterns in habitat use of Western gorilla, as little is known about this species' movements and inter-group competition in the wild. Inter-unit competition will be examined through a comparison of the ranging and dietary patterns of two adjacent Western gorilla groups of contrasting size. This data will assist in the formulation of a predictive model of habitat use strategies that can be tested in other areas and compared to mountain gorillas.
Gorilla group dynamics
Little is known about inter-group dynamics, how groups move relative to each other, the extent home ranges overlap or the strategies males employ to acquire/retain females. Further investigating inter-group dynamics at Bai Hokou will continue to uncover the role social factors play in determining western gorilla movement patterns.
This year has seen quite some progress in both the habituation of the gorillas and in the study of factors affecting habitat use in western gorillas. Visits to the Munye group have continued to be enjoyed by tourists and the second group, Makumba, have advanced considerably in their habituation. There were home range shifts exhibited by both groups, and a loss of the Munye group's sole female as she joined another group.
To complement the dietary data taken daily, phenological monitoring of major gorilla food trees was initiated in January and continued by the trained local field assistants (Flavien Pani and Guy Prosper) during my 3-month absence at the Max Planck Institute or Evolutionary Anthropology (MPIEVA). Equally important in assessing food availability, a pilot transect (2km) was also completed to assess the estimated number of food species per area. This will be used to calculate the length of transects required within each quadrant of the study site to determine the density and distribution of herb and tree species eaten by the gorillas.
Individuality and Comparative Health
Faecal samples have been taken throughout the year for DNA and parasite analysis. DNA samples are currently being analysed by Brenda Bradley at MPIEVA. Those completed from the Munye group confirmed our suspicions that Ndimbelimbe is a male (very difficult to determine before puberty when more salient secondary sexual characteristics develop). It is hoped that more analysis of the Makumba samples will give us a better idea of the groups' composition and sex ratio and also distinguish them from 2 equally-sized neighbouring groups in the south of their range. Further samples will be collected for the remainder of the study period, including from solitary males and groups found within proximity to the study groups. These samples will be examined along with the associated ranging data to assess if there is any relation between the position of group and solitary male home ranges and male relatedness.
This year has seen the tragic demise of the entire study population of gorillas at Lossi, Republic of Congo to Ebola. Apart from Bai Hokou and Mondika (solely research), both in Central African Republic, these were the only other habituated groups of western gorillas. This ecological catastrophe emphasises the need for caution on finding dead animals, especially primates. During this year we have seen one sick silverback that ranged around camp for about a week before dying adjacent to the clearing next to camp. Another putrefying body of a silverback was found during a contact with Makumba. As a consequence of these observations and the situation in nearby Republic of Congo, Chloe Cipolletta and David Greer, the co-directors of the Primate Habituation Programme, organised a meeting with local villagers to increase their awareness on the risks of Ebola transmission, additionally dissuading them from illegal hunting of endangered primates.
Another new addition this year has been the establishment of a permanent team of anti-poaching guards at Bai Hokou (as opposed to irregular missions). This ensures the protection of the gorillas and a rapid response to any signs of poaching within the area. The relocation proved immediately successful with the discovery of poachers with smoked gorilla meat and a live, grey-cheeked mangabey monkey just outside the study site. The young monkey was subsequently released near camp, the poachers imprisoned and the case is currently being processed by the courts.