Impala  (Aepyceros melampus)

The common impala is not yet considered to be threatened; however, the black-faced impala has been assessed as vulnerable to extinction (1). In Angola, the black-faced impala is thought to be nearly extinct (8), and in Namibia, the population has been decimated by drought and increased hunting pressure during periods of war (8). To guard against its extinction in this region, 310 individuals were moved to Etosha National Park in 1968-1971, where the population has steadily grown to over 1,500 (5). Naturally occurring populations in Namibia outside this protected area remain fragmented and threatened by poaching and competition with livestock, and presently (2007) number less than 500 individuals (5) (8).

Black-faced impala from Etosha National Park were subsequently moved to private farms in northern Namibia. Whilst well intended, the movement of black-faced impala to many farms which also hold common impala, has resulted in the potentially serious threat of interbreeding. Although there is no direct evidence of this yet, it is widely believed to occur on farms with mixed herds (8). Interbreeding between subspecies also poses a potential threat to the black-faced impala of Etosha National Park, due to the purchase of common impala by neighbouring farms. Fortunately, there is as yet no evidence of interbreeding within the park (9).

Ironically, the listing of the black-faced impala as Endangered by the U.S. Department of the Interior in 1980 has exacerbated the problem of interbreeding. American trophy hunters do not hunt the black-faced impala because they are not permitted to import the trophies into the United States. Without the incentive of the high-spending American market, few Namibian farmers are willing to pay high prices for black-faced impala when they can buy common impala cheaply. Interviews with Namibian farmers indicate that the lack of American hunting revenues provides no incentive for farmers to prevent interbreeding between the black-faced and common impala (8).

The translocation of the black-faced impala to Etosha National Park has successfully created a population that is less threatened by poaching and competition, than those outside the park. However, care should be taken to ensure that the Etosha population does not come into contact with common impala, which could threaten their persistence due to interbreeding. This highlights the need for conservation of black-faced impala populations in areas removed from farms containing common impala. Solving the problem of interbreeding in private farm populations requires cooperation between governments and private land owners. Political action may be required, as permitting the import of black-faced impala trophies to the United States would create an economic incentive for farmers to maintain pure black-faced impala populations. Raising awareness in farmers of the uniqueness and rarity of the black-faced impala would also aid conservation efforts (8).