Habitat Ecologique et Liberteo des Primates: re-introduction of central chimpanzees to the Conkouati-Douli National Park, Republic of Congo

Summary

Central chimpanzees (Pan troglodytes troglodytes), Endangered and declining from habitat loss, poaching and disease, have been reintroduced to the Republic of Congo's Conkouati-Douli National Park since 1996 by the Congolese charity Habitat Ecologique et Liberte des Primates, releasing orphaned, often infant chimpanzees confiscated from the bushmeat and pet trade into a 21 km2 river-bounded release zone called the Triangle. After years of planning informed by disease-risk and site-suitability studies, chimpanzees were first trained on forested islands in the Conkouati Lagoon to build survival skills before human support was gradually withdrawn, though since 2005 very young, still-dependent infants have instead been taken directly to the release zone with ongoing caretaker supervision and supplemental feeding as part of a separate rehabilitative track not counted in survivorship statistics. Between 1996 and 2001, 37 wild-born chimpanzees, disease-screened and genetically confirmed unrelated, were released in groups or pairs with no post-release supplemental feeding, tracked daily by radio telemetry and behavioral observation from nest to nest. As of November 2009, 35% of released chimpanzees were confirmed alive and nutritionally and behaviorally independent, some free-ranging for as long as 13 years, but 24% were confirmed dead, including 60% of released males, and 38% had unknown fates, with monitoring intensity deliberately reduced since 2008 to encourage full reinsertion into the wild. Major difficulties included balancing chimpanzee welfare against disease risk to the small resident wild population and the challenges of tracking wide-ranging animals long-term. The project rates itself Partially Successful, citing meaningful survival and behavioral independence alongside substantial uncertainty and male mortality.