Mitogenome-based genetic management of captive Great Hornbill in Thailand: Implications for reintroduction

Abstract

The Great Hornbill (Buceros bicornis) is globally vulnerable due to high rates of deforestation and hunting and are therefore a target for restoration. Captive breeding programs in Thailand maintain many Great Hornbills, however active genetic management of captive hornbills was not incorporated into the species recovery plan. With Great Hornbill reintroductions planned for northern Thailand in the immediate future, lack of genetic profiles and phylogenetic relationships among potential founders might hamper population recovery efforts. We assessed the mitochondrial genome (mitogenome) diversity, genetic structure, and evolutionary history of 97 captive Great Hornbills across five zoos in Thailand. Among the 97 samples, we found 21 haplotypes with a haplotype and nucleotide diversity of h = 0.81336 ± 0.021 and pi = 0.00108 ± 0.00040, respectively. The maintenance of mitogenome diversity and no genetic differentiation between five captive populations (FST = 0.00000–0.09723, p > 0.05) might be a result of frequent founder exchange among facilities. Phylogenetic analysis revealed the existence of a southern clade BBITH13, indicating a genetically distinct southern population. To protect these genetic lineages and maintain adaptability of hornbills that have been reintroduced, breeding facilities that contain unique haplotypes should be given high priority in breeding plans. Our data support the evolutionary value of the captive hornbill population in Thailand and highlight the significance of incorporating active genetic management strategies into the species recovery plan for Great Hornbills.