Non-invasive genetic identification confirms the presence of the Endangered okapi Okapia johnstoni south-west of the Congo River

The okapi Okapia johnstoni, a rainforest giraffid endemic to the Democratic Republic of Congo, was recategorized as Endangered on the IUCN Red List in 2013. Historical records and anecdotal reports suggest that a disjunct population of okapi may have occurred south-west of the Congo River but the current distribution and status of the okapi in this region are not well known. Here we describe the use of non-invasive genetic identification for this species and assess the success of species identification from dung in the wild, which varied throughout the range. This variation is probably attributable to varying okapi population densities and/or different sample collection strategies across the okapi's distribution. Okapi were confirmed to occur south-west of the Congo River, in scattered localities west of the Lomami River. We demonstrated that non-invasive genetic methods can provide information on the distribution of cryptic, uncommon species that is difficult to obtain by other methods. Further investigation is required to genetically characterize the okapi across its range and to investigate the biogeographical processes that have led to the observed distribution of okapi and other fauna in the region.