Wild bongo density estimation and population viability analysis improves conservation management

Bongo (Tragelaphus eurycerus eurycerus) are rare, mostly nocturnal forest antelopes in tropical Africa that are prized by trophy hunters for their large size, curved horns, and colorful pelage. Estimating bongo population size is difficult because of their low densities and forested habitat, and therefore management decisions have not previously been based on realistic models of population dynamics. In this study, we estimate bongo density and population size in a safari hunting concession in northern Republic of Congo using spatially explicit capture-recapture (SECR) models based on camera trap data. The SECR bongo population estimates were used to model population dynamics under different scenarios of regulated and unregulated harvest and catastrophic natural events. Bongo density in the safari hunting concession was 8.77 bongo 100 km-2 (4.78-15.58). Vortex modelling showed that trophy hunting quotas granted previously would, if achieved, have led to rapid local extinction of bongo. As a result of this study, quotas were reduced to three bongo per year, which is only sustainable if current optimal conditions are maintained.