Southern Africa's Blue wildebeest (Connochaetes taurinus) and Black wildebeest (Connochaetes gnou) are currently at the centre of a hybridisation controversy.
The endemic Black wildebeest is believed to have originated from a Blue wildebeest-like ancestor around a million years ago. Historically the distribution of the two species overlapped, but in the past hybridisation may have been prevented by the presence of abundant species-specific mates and the absence of restrictions to migration.
In recent times, hybridisation has become a reality in introduced and endemic ungulates. This has been caused mostly by artificial management characterised by small population size, fences and the absence of species-specific mates, which have resulted in a potentially large number of hybridisation events.
In southern Africa, the endemic Black wildebeest (Connochaetes gnou) survived near extinction in the late 1800s and again in the 1930s.
Blue wildebeest (Connochaetes taurinus).
First generation Black wildebeest x Blue wildebeest hybrid.
In southern Africa, the endemic Black wildebeest survived near extinction and consequent genetic bottlenecks in the late 1800s and again in the 1930s. Initiatives by private farmers, followed by initiatives by conservation authorities, have led to a dramatic recovery in numbers of this species.
Now these very same advances in conservation and commercial utilisation are threatening the species. The endemic Black wildebeest currently faces a serious threat of hybridisation. The hybrids are fertile. Already hybridisation between Black and Blue wildebeest has occurred at numerous localities in South Africa through injudicious translocations. The consequence is that a significant proportion of the national Black wildebeest population potentially carries a proportion of Blue wildebeest genetic material.
Research will assist in judicious management of the species
This state of affairs has given rise to a multi-disciplinary project with collaborators from the University of the Free State, University of Pretoria, the Ecological Advice Division, Ezemvelo KwaZulu-Natal Wildlife, Florisbad Quaternary Research, National Museum, Free State Department of Economic Development, Tourism and Environmental Affairs, and the Tshwane University of Technology.
National Zoo researchers have made huge strides towards finding species specific markers and SNPs (short nuclear polymorphisms) to detect hybrids and advanced backcrosses and hybrid herds. The lack of consensus on the fate of hybrid herds is still a contentious issue.
Against a background of scant information, research at this stage indicates a need to be cautious in implementing management responses that will potentially induce a new genetic bottleneck in C. gnou.
Antoinette Kotze, Manager, Research and Scientific Services Department, NZG
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