Mitochondrial DNA diversity of the eastern black rhinoceros (Diceros bicornis michaeli) in Tanzania: implications for future conservation

There has been a drastic decline in the number of eastern black rhinoceros (Diceros bicornis michaeli) across Africa, leaving individuals restricted to small, isolated populations that are vulnerable to extinction. Focusing on highly threatened populations in Tanzania, this study investigated the genetic impacts of past management interventions on mitochondrial control region diversity in extant subpopulations, assessed whether there has been evidence of dispersal of females between populations based on haplotype sharing, and related current haplotype diversity to historical patterns. Across extant subpopulations in Tanzania, six maternal haplotypes were identified, with an overall haplotype diversity of h = 0.72 but lower overall nucleotide diversity within populations (& pi; = 0.017) compared to historical populations (& pi; = 0.021). Translocated populations did not share haplotypes with native populations, even though all haplotypes from translocated individuals had been found among historic samples from Kenya. This suggests that translocations have been successful at restoring previous diversity to the region but that the current Intensive Protection Zone (IPZ) management practices have restricted the movement of females between subpopulations. Extant haplotypes were distributed among three East African haplogroups described in previous studies, suggesting that multiple lineages have been preserved despite the loss of historical haplotypes. Our recommendation is to enhance the utilisation of previous translocations by enabling the natural movements of individuals between subpopulations. Such a change in management strategy could be less costly both economically and in terms of animal welfare than the alternative of using genetic data to target specific animals for translocation in order to supplement diversity.

Automated summary

The number of eastern black rhinoceros (Diceros bicornis michaeli) in Africa has significantly declined, resulting in small, isolated populations that are at risk of extinction. This study in Tanzania focused on threatened populations and examined the genetic effects of past management interventions, the potential dispersal of females between populations, and the relationship between current and historical haplotype diversity. The findings suggest that translocations have successfully restored previous diversity, but current management practices have limited female movement between subpopulations.