WCS has been surveying eastern chimpanzee populations in Uganda (Andrew Plumptre), eastern Democratic Republic of Congo (John Hart, Deo Kujirakwinja), Rwanda (Andrew Plumptre and Michel Masozera) and Tanzania (Andrew Plumptre and Tim Davenport). As such we have more information about this species in the Albertine Rift than any other conservation organisation.
Chimpanzees are a good indicator of the health of conservation of an area. They are at increased risk of becoming extinct at a site because they live at low densities and have a very slow reproductive rate (one infant born every 5 years on average).
In Uganda WCS worked with the Jane Goodall Institute, Uganda Forest Department and Uganda Wildlife Authority to survey all large forests where chimpanzees occur and to estimate their numbers. Chimpanzees only occur in the west of the country. The results of this survey were published in the Albertine Rift Technical Reports Series (No. 2). A total of 4,950 chimpanzees were estimated for Uganda. This was higher than had been predicted which was encouraging but only four forests had populations greater than 500 individuals, a number that is often thought to be a minimum requirement for a population to be viable in the long term. There is a need to protect contiguous forests and natural habitats with corridors to ensure the long term survival of this species in Uganda. These results led to the development of a national chimpanzee action plan for Uganda. The results also fed into the national Great Apes Action Plan that was developed for the Great Apes Survival Project of the UN. We are now in the process of supporting the creation of forest corridors in the Murchison-Semliki Landscape to conserve this ape and looking at possible incentives such as funding through REDD to encourage farmers to conserve forest on their land. We have also been supporting follow-up monitoring of chimpanzees in Kibale National Park, and Budongo, Bugoma, Kalinzu, Maramagambo and Kasyoha-kitomi Central Forest Reserves.
In Rwanda we have been involved in the census of chimpanzees in Nyungwe National Park and shown there about 300-350 individuals in this forest. Nyungwe is connected to the Kibira National park in Burundi and estimates of chimpanzees from this park are around 400 individuals making a total of 750 individuals in the Congo-Nile Divide. A report summarising this work is available here.
In Tanzania we worked with Jane Goodall Institute, Kyoto University, Tanapa and Frankfurt Zoological Society to undertake a survey of chimpanzees throughout the Greater Mahale Ecosystem and Southern Tanganyika to estimate about 2,700-2900 chimpanzees for Tanzania as a whole when the Gombe population is also included. Of this the Greater Mahale Ecosystem contains about 2,600 chimpanzees.
Chimpanzees are not hunted much for bushmeat in Uganda, Rwanda, Burundi or Tanzania unlike much of Africa and this makes these countries one of the easiest places to see chimpanzees as a tourist. Densities here are much higher than in the lowland forests of the Congo basin reaching 2-3 per square kilometer.
In DRC we have made surveys of chimpanzees in the proposed Ngamikka National park in the Marungu-Kabogo Landscape in the Itombwe Massif and Kahuzi Biega National park in the Maiko-Itombwe Landscape and in the Virunga Park in the Greater Virunga Landscape. We are in the process of working to conserve the habitat where they occur at these sites.
Compiling all our survey data and working with many other scientists who study the Eastern Chimpanzee WCS led the development of a conservation action plan for IUCN for this subspecies of chimpanzee. We have also collaborated on the development of a more detailed regional plan for chimpanzees and Grauer’s gorilla in eastern DRC.