Biogeography of central African forests: Determinants, ongoing threats and conservation priorities of mammal assemblages

An exhaustive compilation of lists of forest-dwelling mammal species was made from wildlife and bushmeat surveys throughout Central Africa.

A beta diversity approach allowing the clustering of studies composed of similar species was used to identify and delimit zoogeographic districts, separately for three well-documented mammalian orders: carnivores, primates and artiodactyls. Random forest classification models were then used to identify the environmental determinants of district distribution and to produce a continuous zoogeographic map (and associated uncertainties) essential for assessing the conservation status of each district and the threats facing them.

While carnivores do not show a clear spatial structure within the forests of Central Africa, our results highlight the structuring role of rivers on the distribution of primate and artiodactyl assemblages. We selected eight and six spatially congruent districts for primates and artiodactyls, respectively. These districts were shaped by the Ubangi-Congo river system and the Cross and Sanaga rivers, with a secondary role of insularity and rainfall identified for primates. Highly threatened districts have been highlighted, particularly in Nigeria and the Democratic Republic of Congo, the latter including vast areas that have been little studied and poorly represented in the network of protected areas.

As well as refining our understanding of the diversity and uniqueness of mammal assemblages in the forests of Central Africa, the map of zoogeographic districts produced by this study has considerable implications for the conservation of highly threatened taxa, making it possible to target species and areas of interest for more in-depth sampling, conservation and rewilding efforts.