Exciting new genetic research from the University of Venda’s Department of Zoology will be published in the journal Scientific Reports this week. The research defines new management units for the iconic black rhinoceros, a highly endangered species that has been driven to the brink of extinction due to unsustainable poaching.
The world’s rhinoceros species are again on the verge of extinction. In Africa, the browsing black rhinoceros (Diceros bicornis) is much rarer than the grazing white rhinoceros (Ceratotherium simum). This was not always the case. As recently as the 1970s, the black rhinoceros was widespread and a common sight throughout most of sub-Saharan Africa. Unfortunately, ruthless poaching for its valuable horn beginning about the early 1980s sparked a range-wide population collapse so severe, that by 1992, the species could only be found in small isolated pockets in six African countries: Cameroon, Kenya, Tanzania, Zimbabwe, Namibia and South Africa. Thanks to dedicated efforts by conservation authorities and NGOs, the black rhinoceros has made something of a recovery in Kenya, Namibia and South Africa, while the Zimbabwean population remains low but stable. In contrast, Tanzania continues to lose the few black rhinoceros that it has at an alarming and unsustainable rate and the West African population in Cameroon was declared extinct in 2011. To make matters worse, very little is known about the population structure and evolutionary history of the black rhinoceros, the irony being that this very information is crucial to the successful long-term management of genetic diversity and evolutionary potential of these last remaining populations. Furthermore, until now, black rhinoceros populations were managed on the basis of a pragmatic, but simplistic, four-subspecies scheme which divided the vast sub-Saharan range of this species into four regional conservation units in West (Cameroon), East (Kenya and northern Tanzania), South-Central (Southern Tanzania, Zimbabwe and South Africa) and South-West (Namibia) Africa.
The Moodley Lab, L-R: Dr Andrinajoro (Joro) Rakotoarivelo (Postdoctoral Fellow), Mr Thabang Seragke (Bsc Hons), Prof Yoshan Moodley, Ms Monica Hlangwani (MSc), Mr Femi Elegbeleye (MSc).
Given this background, the Molecular Ecology group from the Department of Zoology at the University of Venda (Univen), led by Professor Yoshan Moodley, teamed up with researchers from Cardiff University in the United Kingdom along with an international team of experts, to discover how the remaining five black rhinoceros populations were related to each other, so that this information could inform conservation managers on the ground. This was an extremely ambitious project, because the black rhinoceros is now extinct throughout much of its range, and interpreting any results from just the remaining populations would be
like trying to piece together a large jigsaw puzzle with just five pieces. So Moodley turned to museum collections in Europe, the United States and Africa, which house historical (18th and 19th Century) collections of black rhinoceros material (skin and bones) from which genetic material was obtained, and compared to the five remaining populations for a complete species-wide picture.
The results of this study will be published this week in the prestigious journal Scientific Reports, and show that 20th Century population collapses were responsible for the loss of 69% of the species’ mitochondrial genetic variation, including the most ancestral lineages which are now absent from modern populations. Genetically unique populations in countries such as Nigeria, Cameroon, Chad, Eritrea, Ethiopia, Somalia, Mozambique, Malawi and Angola no longer exist. Moodley also found that the historic range of the “extinct” West African population actually extends into southern Kenya, where a handful of individuals survive in the Masai Mara-Serengeti ecosystem. Most importantly, the paper identifies precise conservation units that if properly managed, will maintain the species’ remaining evolutionary potential for generations to come. Since these recommendations are largely odds with the current management scheme, it will require a complete re-evaluation of conservation management paradigms for the black rhinoceros. Moodley and his team are presently continuing this important work at the genomic level, searching for signatures of natural selection which will be used to inform an integrated approach to the conservation of adaptive genetic variation among remaining black rhinoceros populations.
This study underscores the immense value of historic museum collections in present-day species conservation and yet again highlights the University of Venda as an international authority on conservation and evolutionary genetics.
For more information, please contact Professor Yoshan Moodley at 015 962 8453/0785865739 or email to Yoshan.Moodley@univen.ac.za
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