Western gorilla re-introduction to the Batéké Plateau region of Congo and Gabon

Summary

The UK charity The Aspinall Foundation has coordinated re-introduction of the Critically Endangered western gorilla (Gorilla gorilla gorilla) to the Batéké Plateau region of Congo and Gabon since 1987 and 1998 respectively, through the Projet Protection des Gorilles, aiming to establish self-sustaining populations in areas where the species had been extirpated. Release stock, mostly wild-born orphans confiscated from the bush-meat trade plus some hand-reared captive-born individuals from the Foundation's UK parks, undergo lengthy rehabilitation before soft release in groups of three to seventeen. The first releases, in Congo's Lesio-Louna Reserve from 1996, achieved high survival but were abandoned due to lack of ecological barriers separating gorillas from people; survivors were relocated to the neighboring Lefini Reserve in 2003 to 2004. In Gabon's Batéké Plateau National Park, two groups were released in 2001 and 2004. Between 1996 and 2006, 51 gorillas were released, 25 in Congo and 26 in Gabon, with overall post-release survival of 84 percent in Congo and 84.6 percent in Gabon regardless of sex or captive-versus-wild origin. Released gorillas feed on over 100 native plant species, range like wild gorillas, and exhibit natural social behaviors including female transfer; six babies have been born to re-introduced groups over four years. Two protected areas have been created through the program. The project rated itself Highly Successful for survival, adaptation, and reproduction, though it noted it is still too early to confirm long-term self-sustaining population viability.