Species Diversity and Habitat Use of Primates in Afi Mountain Wildlife Sanctuary, Cross River State

This study documents the species diversity and habitat use of primates in Afi Mountain Wildlife Sanctuary (AMWS), Cross River State, located in Nigeria's South South geopolitical zone. Afi Mountain is a globally recognised primate conservation site hosting endemic and endangered species, yet updated baseline survey data using standardised methods are needed to assess population trends and inform management. Line transect surveys of 15 km were walked repeatedly at four sites within the sanctuary during morning and afternoon survey periods over 60 days. All primate encounters were recorded with group size, GPS position, habitat type, and perpendicular sighting distance. Camera traps supplemented surveys for ground-dwelling species. Eight primate species were confirmed, including Cross River gorilla Gorilla gorilla diehli, Nigeria-Cameroon chimpanzee Pan troglodytes ellioti, Preuss's monkey Allochrocebus preussi, and drill Mandrillus leucophaeus, all of which are critically endangered or endangered on the IUCN Red List. Encounter rates for gorilla and chimpanzee were highest in montane forest above 900 metres. Forest disturbance from farmland incursion was recorded at five of 15 transect segments. The study recommends urgent boundary demarcation and enforcement, community engagement to reduce agricultural encroachment, and continued long-term primate monitoring as priority conservation actions for AMWS. Keywords: primates, Afi Mountain, Cross River gorilla, wildlife sanctuary, species diversity.