Conservation genetics of the white-bellied pangolin in West Africa: a story of lineage admixture, declining demography and wide sourcing by urban bushmeat markets

Abstract

During the last 40 years, the volumes of African pangolins feeding the illegal wildlife trade have dramatically increased. We conducted a conservation genetics survey of the most traded African species, the white bellied pangolin (WBP; Phataginus tricuspis), across three West African countries including Guinea, Cote dIvoire and Ghana. Our study combining mitochondrial DNA (mtDNA) sequencing and microsatellites genotyping is the first to reveal a global pattern of admixture between two of the six mitochondrial lineages as previously delimited within WBP. We found a signature of isolation-by-distance and a lack of population genetic structuring, supporting the idea that WBP may have underestimated dispersal abilities. Levels of genetic diversity were low compared to central African lineages, reinforcing the picture of genetic pauperization shared by West African WBP. We observed a 85-98% decline in the effective population size of WBP occurring c. 3200 to 400 ya, with current numbers (520-590) at the lower end of the conservative thresholds for minimum viable population size. The microsatellites markers were powerful enough to differentiate between individuals and identify replicated samples, confirming the utility of this approach in tracing the pangolin trade. Genetic diversity estimates confirmed that Yopougon, the main bushmeat market from Abidjan (Cote dIvoire), was fed by a large trade network as confirmed by vendors reporting 10 different sources situated 62-459 km away from the market. We conclude that WBP distributed in the Upper Guinean Block should be considered a single management unit of high conservation concern, as impacted by genetic diversity erosion, drastic decline in effective population size and wide range sourcing for feeding urban bushmeat markets. Given the genetic admixture pattern detected within WBP from West Africa, we advocate for a multi-locus strategy to trace the international trade of the species.