Population Status of the Critically Endangered Preuss’s Red Colobus Monkey ( Piliocolobus preussi Matschie 1900) and Recommendations for Its Conservation

Overhunting and habitat loss from the expansion of agriculture and extractive industries are the primary threats to primate species, 65% of which are threatened with extinction. In Africa, red colobus ( Piliocolobus spp.) are the most endangered group of monkeys due to their vulnerability to these human pressures. The conservation status of the Critically Endangered Preuss’s red colobus ( P. preussi ), found in southeastern Nigeria and western Cameroon, is not well understood, impeding conservation efforts. We reviewed historical records and recent data on the distribution and abundance of Preuss’s red colobus to assess the species’ population status and provide recommendations for its conservation. Preuss’s red colobus has historically been found in two widely separated populations: one in the contiguous transboundary forests of Nigeria’s Cross River National Park (Oban) and Cameroon’s Korup National Park, and the other in Cameroon’s Ebo–Makombe–Ndokbou forests. Today, Preuss’s red colobus is mostly restricted to Korup and Oban and has largely disappeared from the Ebo–Makombe–Ndokbou forests. Systematic surveys indicate that the population in Korup, where Preuss’s red colobus reaches its highest density, has declined over the last 30 years with possibly 3290–4430 red colobus monkeys remaining. Improving protection of the Korup–Oban population, through improved law enforcement, transboundary conservation, ecological monitoring, and engagement with adjacent local communities, is essential to secure the long-term survival of Preuss’s red colobus. Locating and protecting remnant groups in other forests is also urgently needed. Protecting Preuss’s red colobus will help safeguard some of West Africa’s largest remaining intact forests and other threatened wildlife species.