Landscape Genetics of Chimpanzees and Implications for Conservation Planning

Conservation genetics is now at crossroads, particularly with respect to relatively well-studied flagship species like chimpanzees. Genetic studies of wild chimpanzees have been crucial for reconstructing phylogenies and identifying geographical boundaries important in delimiting chimpanzee taxa – but is this the limit of how we can use conservation genetics data? Here we discuss the use of chimpanzees in Cameroon as a model to highlight how next-generation sequencing technologies and geospatial modeling may be used to address specific conservation questions. Cameroon is home to two subspecies of chimpanzee. Using genetic data, including microsatellite genotypes and mitochondrial control region sequences of wild chimpanzees, we have found that chimpanzees in Cameroon comprise at least two, and likely three populations. Genetic data suggests that there is a primary separation of Pan troglodytes troglodytes in southern Cameroon from P. t. ellioti north and west of the Sanaga River. These two populations split ~200-250 thousand years ago (kya), but have exchanged one migrant per generation since separating.  In addition, P. t. ellioti consists of two populations that split from one another ~4 kya. This region also contains diverse habitats, and forms a unique ‘natural laboratory’ not only for studying the forces that drive evolutionary diversification of chimpanzees, but to also addressing conservation concerns.  Using a spatially explicit approach based upon Generalized Dissimilarity Modeling, we have found that both the Sanaga River and environmental variation were found to contribute to driving separation of the subspecies. Mapping adaptive genetic diversity, as well as other patterns of chimpanzee diversity including variation of the gut microbiome, is vital in our ability to conserve both the rich patterns found in chimpanzees across this region as well as the evolutionary processes that produced them. We will extend this discussion to potential future studies comparing genetic data of chimpanzees to complementary data from co-distributed taxa and use geospatial modeling to better predict how climate change might affect chimpanzees and their habitats over the next century.