Impact of Environmental and Anthropogenic Factors on Mandrill (Mandrillus sphinx) Occupancy and Habitat Use in Monte Alén National Park, Equatorial Guinea

Abstract

Understanding the ecological and anthropogenic factors shaping primate distribution is critical for effective conservation, particularly for species threatened by habitat loss and hunting. This study investigates factors influencing mandrill (Mandrillus sphinx) occupancy in Monte Alén National Park (MANP), Equatorial Guinea, a protected area with diverse habitats. Using 35 camera traps over 10,858 trap-days, we recorded 79 mandrill detections (48 in the wet season, 31 in the dry season) and estimated naïve occupancy at 24%. We applied single-species, single-season occupancy models to evaluate the effects of environmental and anthropogenic factors, including proximity to water bodies, hunting camps, villages, park boundaries, and terrain slope. Occupancy probability decreased with distance from water, indicating dependence on riparian habitats, while slope had no major effect. Proximity to hunting camps also influenced mandrill distribution, with higher occupancy observed farther from these areas. Seasonal analysis suggested that mandrills concentrated in resource-rich areas during the wet season, highlighting flexible, site-specific habitat use. These results emphasize the combined influence of environmental resources and human pressures on mandrill space use. Effective conservation should focus on protecting critical habitats near water sources and regulating human activity around hunting areas. More broadly, our findings improve understanding of how ecological, anthropogenic, and socioeconomic factors shape primate distribution, offering insights relevant for the conservation of other vulnerable species across Central Africa.