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Grauer’s Gorilla at Extremely High Risk of Extinction in the Wild

The Wildlife Conservation Society made this announcement today at the IUCN World Conservation Congress currently underway in Hawaii:

An infant gorilla rides on the back of an adult. CREDIT: A.J.Plumptre/WCS.
An infant gorilla rides on the back of an adult. CREDIT: A.J.Plumptre/WCS.

Grauer’s gorilla (Gorilla beringei graueri), a subspecies of eastern gorilla, the world’s largest ape, and confined to eastern Democratic Republic of Congo, has been listed as Critically Endangered on the IUCN Red List of Threatened Species. The IUCN Red List classifies species of the world and documents the threats they are facing. It is recognized as the global standard on the conservation status of species. Critically Endangered status means that a species is considered to be facing an extremely high risk of extinction.

The new designation follows a report earlier this year released by WCS and Fauna & Flora International (FFI) that showed a shocking collapse of Grauer’s gorilla numbers due to illegal hunting and civil unrest.

“We are grateful that IUCN and the Species Survival Commission Primate Specialist Group have accepted our recommendations to upgrade the listing of Grauer’s gorilla,” said Andrew Plumptre, senior conservationist in the Uganda Program of WCS, and the lead author of the revised listing, “Critical Endangered status will raise the profile of this gorilla subspecies and bring attention to its plight. It has tended to be the neglected ape in Africa, despite being the largest ape in the World.”

A Grauer’s gorilla silverback in a tree. CREDIT: A.J.Plumptre/WCS.
A Grauer’s gorilla silverback in a tree. CREDIT: A.J.Plumptre/WCS.

Few Grauer’s gorillas exist in captivity and if this ape becomes extinct in the wild it will be effectively lost forever. This listing also means that the two gorilla species (eastern and western gorillas) and four gorilla subspecies (two for each species) are all Critically Endangered.

The WCS and FFI surveys documented that Grauer’s gorilla has declined by at least 77 percent over the past 20 years using three methods of estimation; the other methods estimated up to a 94 percent decline at specific sites where they have been monitored over time. A decline in 80 percent over the time span of three generations leads to a listing of Critically Endangered status. Twenty years is considered to be only one generation time for these gorillas as they are a long-lived ape.

Map of Protected Areas (including Kahuzi-Biega National Park) in eastern Democratic Republic of Congo. CREDIT: Courtesy of WCS.
Map of Protected Areas (including Kahuzi-Biega National Park) in eastern Democratic Republic of Congo. CREDIT: Courtesy of WCS.

These apes are therefore declining very rapidly across their range. Only one site, the highland sector of Kahuzi-Biega National Park, has shown an increase over the past 15 years where resources have been invested to protect these apes from hunting. These results have just been accepted for publication in PLoS One, an open source and peer reviewed scientific journal.

Skulls of poached Grauer’s gorillas. CREDIT: A.J.Plumptre/WCS.
Skulls of poached Grauer’s gorillas. CREDIT: A.J.Plumptre/WCS.

The main cause of the decline is hunting for bushmeat, which is taking place around villages and mining camps that have been established by armed groups deep in the forests in eastern DR Congo. The mines are set up in remote areas to provide the financing for weapons to continue the armed struggle by these groups. Being deep in the forest to avoid detection, they are also in the areas where gorillas have tended to survive because of the remoteness and distance from villages and roads. There is no agriculture in these sites, so the miners/rebels can only subsist off bushmeat and gorillas provide more meat than most species per shotgun cartridge and can be tracked fairly easily because they are mainly terrestrial and move in a group, making them particularly vulnerable to hunting.

Map of probability of gorilla occurrence in eastern Democratic Republic of Congo (with green indicating higher occurrence). CREDIT: Courtesy of WCS.
Map of probability of gorilla occurrence in eastern Democratic Republic of Congo (with green indicating higher occurrence). CREDIT: Courtesy of WCS.

Said WCS DRC Project Director Deo Kujirakwinja, who has established the data collection across most of Grauer’s range: “The data used to estimate this decline came from park rangers of the DR Congo protected area authority ICCN as well as local communities which are entered in software called SMART (Spatial Monitoring And Reporting Tool). It shows the value of such monitoring databases once established and it is vital they continue to be supported to allow us to continue to monitor the gorillas in future.”

Said Richard Tshombe, WCS’s Country Director for DR Congo: “The survey results helped us to identify critical sites for the conservation of the remaining gorillas. We have already started engaging communities in one area to protect the gorillas in the Punia Gorilla Reserve, and we continue to support their conservation in Kahuzi-Biega National Park.  In addition, we helped establish the Itombwe Reserve in June 2016 which protects a second important population.”

Bamboo forest near the summit of Mt. Kahuzi. CREDIT: A.J.Plumptre/WCS.
Bamboo forest near the summit of Mt. Kahuzi. CREDIT: A.J.Plumptre/WCS.

Tim Tear, Executive Director of the WCS Africa Program, emphasized the importance of investing more in conservation. “Overall, this study has startling news – based on data gathered in very difficult and challenging circumstances. However, the positive news from Kahuzi-Biega National Park is a beacon of hope.  It demonstrates that if we continue to invest in conservation of this gorilla, we can make a difference.  This is a wake-up call that demands more investment to support conservation in the field if we are to save this species.”

With this new listing, both species and all four subspecies of gorilla (Grauer’s, western lowland, Cross River and mountain gorilla) are now considered Critically Endangered; and WCS is working to improve their conservation status across Africa.

A Grauer’s gorilla silverback male. CREDIT: A.J.Plumptre/WCS.
A Grauer’s gorilla silverback male. CREDIT: A.J.Plumptre/WCS.

The WCS/FFI report, funded by the Arcus Foundation, analyzed data collected with support from Critical Ecosystem Partnership Fund, KfW (German Development Bank), ICCN, Rainforest Trust, UNESCO, USAID, U.S. Fish and Wildlife Service, World Bank. The Red List assessment was prepared by the IUCN SSC Primate Specialist Group.

Park rangers carrying out an anti-poaching patrol in Kahuzi-Biega National Park. CREDIT: A.J.Plumptre/WCS.
Park rangers carrying out an anti-poaching patrol in Kahuzi-Biega National Park. CREDIT: A.J.Plumptre/WCS.
While the video above was being finalized, the chief park warden of Kahuzi Biega notified WCS that Oscar Mianziro, one of the rangers who monitored the habituated gorillas, was killed on March 31, 2016, by armed rebels in an ambush on the park. Our deepest condolences go to his family and to his colleagues. Helping these courageous men and women is vital. Please consider supporting them and the challenging work they do. Go to WCS.org