Biodiversity Conservation in Sub-Saharan Africa: A Case Study of the African Dwarf Crocodiles (Osteolaemus Spp.)

Overexploitation of wildlife is a leading threat to biodiversity in tropical Africa. Effective management requires integrating information on the extent of exploitation, distribution, and status of exploited species. I explore how trade filters affected the final destination of bushmeat for different species involved in the trade. I highlight the trade in reptiles, in particular African Dwarf Crocodiles (Osteolaemus tetraspis) to investigate why they are rare in markets yet ubiquitously hunted. Hunting locations and methods determined the types of species entering bushmeat markets while selling conditions and prices determined whether species were traded locally or in urban markets.

To prioritize conservation efforts of over-exploited species, it is important to determine the distribution and status of populations. I conducted detailed sampling of Osteolaemus populations in Cameroon and around the Cameroon Volcanic Line (CVL), to investigate the distributional limits and number of cryptic Osteolaemus species in the country. I found that O. tetraspis extends west beyond the CVL, thus, this mountain chain does not represent the distributional limit of this species. I also found O. osborni in Cameroon. I provided information on the population ecology of O. tetraspis and O. osborni in Cameroon to facilitate independent conservation of these two species. Both species are threatened in Cameroon based upon low encounter rates, young population structures and continued threats of habitat loss and hunting pressure.

Crocodilians link nutrients and energy between food webs through their movements across heterogeneous habitats. These connections may differ among habitats and as they undergo ontogenetic shifts in diet. I compared food web associations of Ostoelaemus species inhabiting a large river and small tributary using stable isotope analyses of carbon and nitrogen. Osteolaemus species inhabiting perennial rivers have aquatic food web associations as opposed to the largely terrestrial food web associations detected when they occupy swamp habitats. These species have large dietary overlap between juveniles, adults and, sexes.

Through my research, I have provided a working knowledge of the distribution, ecology, and hunting pressure of Osteolaemus species necessary for assessing their conservation status and developing sound management. These widely distributed species should be regionally managed to conserve their evolutionary diversity.