Western Gorilla - Conservation Status

Conservation Status

The World Conservation Union lists the western gorilla as critically endangered, the most severe denomination next to global extinction, on its 2007 Red List of Threatened Species. The Ebola virus might be depleting western gorilla populations to a point where their recovery might become impossible, and the virus decimated populations in protected areas by 33% from 1992 to 2007, which may be equal to a decline of 45% for a period of just 20 years spanning 1992 to 2011. Poaching, commercial logging and civil wars in the countries that compose the western gorillas' habitat are also threats. Furthermore, reproductive rates are very low, with a maximum intrinsic rate of increase of about 3% and the high levels of decline from hunting and disease-induced mortality have caused declines in population of more than 60% over the last 20 to 25 years. Rather, under the optimistic estimate scenarios, population recovery would require on the order of 75 years. Much sooner, perhaps 20 to 30 years in the future, habitat loss and degradation from agriculture, timber extraction, mining and climate change will become a major threat. Thus, a population reduction of more than 80% over three generations (i.e., 66 years from 1980 to 2046) seems likely.

In the 1980s, a census taken of the gorilla populations in equatorial Africa was thought to be 100,000. Researchers adjusted the figure after years of poaching and deforestation had reduced the population to approximately 50,000. Surveys conducted by the Wildlife Conservation Society in 2006 and 2007 found more than 100,000 previously unreported gorillas have been living in the swamp forests of Lake Tele Community Reserve and in neighbouring Marantaceae (dryland) forests in the Republic of the Congo. With the new discovery, the current population of western lowland gorillas could be around 150,000–200,000. However, the gorilla remains vulnerable to Ebola, deforestation, and poaching.

Estimates on the number of Cross River gorillas remaining is 250–300 in the wild, concentrated in approximately 9-11 locations. Recent genetic research and field surveys suggest these locations are linked by the occasional migration of individual gorillas. The nearest population of western lowland gorilla is some 250 km away. Both loss of habitat and intense hunting for bushmeat have contributed to the decline of this subspecies. A conservation plan for the Cross River gorilla published in 2007 outlined the most important actions necessary to preserve this subspecies. Richard Black of the BBC has reported the government of Cameroon has created the Takamanda National Park on the border with Nigeria, as an attempt to protect these gorillas. The park now forms part of an important trans-boundary protected area with Nigeria’s Cross River National Park, safeguarding an estimated 115 gorillas—a third of the Cross River gorilla population—along with other rare species. The hope is these gorillas should be able to move between the Takamanda reserve in Cameroon over the border to Nigeria's Cross River National Park.