Patterns of genetic diversity in African forest elephants living in a human‐modified landscape in southwest Gabon

Abstract

We investigated the patterns of genetic diversity and structure of African forest elephants in a human‐modified landscape in the Gamba complex of protected areas (GCPA), a tropical wilderness area along the southwest coast of Gabon. We collected 298 elephant fecal samples from four sites (Sette Cama, Gamba area, Vera Plains, and Mayonami), along approximately 80 km of coastline from north to south. We used microsatellites and mitochondrial DNA (mtDNA) to successfully genotype 295 of the 298 fecal samples, and identified 213 individuals. Using sex markers, we identified 84 males and 118 females; we could not determine the sex of the remaining 11 individuals. We also characterized the sex, group size, and social status of crop‐raiding elephants and did not find characteristics distinguishing them from nonraiders. Overall, our mtDNA and microsatellite markers revealed that elephants in the research area maintain high levels of genetic variation and low levels of subdivision. Gene flow appears to be mostly mediated by male dispersal away from natal herds. Our structure analysis revealed two highly admixed genetic clusters, attributable to high connectivity among the protected areas. However, forest areas within the GCPA have become increasingly fragmented by human‐induced habitat modification. We detected a pattern of isolation by distance, accentuated by the presence of the town of Gamba between Sette‐Cama and Mayonami. We found a high degree of connectivity among sampling locations within the GCPA. This supports the importance of establishing agricultural best practices to reduce habitat loss that may sever gene exchange and to maintain connectivity, as well as to avoid human–elephant conflict that can result in retaliatory killing of elephants in this area. This study emphasizes the importance of conducting baseline monitoring of demographic data, genetic diversity, and structure to enable future comparisons to assess the long‐term impact of human‐induced habitat fragmentation.