Population status, threats, and conservation of Preuss\u27s red colobus (Piliocolobus preussi) and other diurnal primates in the Ndokbou forest, Littoral Region, Cameroon

The Ebo-Makombe-Ndokbou forest block in southwest Cameroon lies within the Gulf of Guinea biodiversity hotspot, characterized by extremely high levels of species richness and endemism, including those of primates. These forests may contain one of the last populations of the Critically Endangered Preuss’s red colobus monkey (Piliocolobus preussi; PRC), which is found only in southeastern Nigeria and western Cameroon. Gun hunting for bushmeat and habitat loss and degradation from logging and agriculture are the main threats to PRC. The conservation status of PRC and other primates in the Ndokbou forest are largely unknown, with most regional research efforts occurring in the nearby Ebo forest. I assessed the population status of and threats to PRC and other diurnal primates in the Ndokbou forest to inform and improve their protection. I conducted forest reconnaissance surveys to estimate primate abundance and distribution and to assess hunting and logging activities. I also deployed acoustic sensors to assess the spatiotemporal patterns of gun hunting. I compared primate abundance and gun hunting in the Ndokbou forest to those from the protected Korup National Park. Overall primate abundance was less than half of that of Korup NP. Of the nine primate species I encountered in the Ndokbou forest, I heard PRC only once. Cercopithecus nictitans was the most abundant species, accounting for 56% of all primate encounters. Recce surveys suggested that gun hunting activity was widespread with no significant variation in geographic distribution. However, acoustic sensors identified higher levels of gun hunting in areas closest to villages and logging roads, while forest surveys failed to show these differences. Mean gunshot frequency, as measured by the acoustic sensors, was 0.46 gunshots/day in the Ndokbou forest compared to 0.55 gunshots/day in Korup NP. Results suggest that logging activities may have facilitated widespread hunting, which has led to the observed low primate abundance for every species. More evidence for the presence of PRC is needed to confirm its presence in Ndokbou, but if they do occur in the Ndokbou forest they are likely restricted to the most remote and rugged areas of the forest with low gun hunting levels. However, despite impacts from logging and hunting, this forest still contains important endangered primate species. The best hope for their protection likely lies in community-led conservation efforts that address wide-spread hunting levels driven by logging operations