African wild dog populations are continuing to decline due to habitat loss and fragmentation, conflict with humans, and infectious diseases that are spread by domestic animals.
The population size of the African wild dog is continuing to decline as a result of ongoing habitat loss and fragmentation, conflict with human activities, and infectious diseases that are spread by domestic animals. The principal threat to African wild dogs is habitat fragmentation, which increases their contact with people and domestic animals, resulting in human-wildlife conflict and transmission of infectious disease.
The important role played by human-induced mortality has two long-term implications. First, it makes it likely that, outside protected areas, African wild dogs may be unable to coexist with increasing human populations unless land use plans and other conservation actions are implemented. Second, African wild dog ranging behavior leads to a very substantial edge effect, even in large reserves. Simple geometry dictates that a reserve of 5,000 kilometers² contains no point more than 40 kilometers from its borders – a distance well within the range of distances traveled by a pack of African wild dogs in their usual ranging behavior. Thus, from an African wild dog’s perspective, a reserve of this size (fairly large by most standards) would be all edge. As human populations rise around reserve borders, the risks to African wild dogs venturing outside are also likely to increase. Under these conditions, only the very largest unfenced reserves will be able to provide any level of protection for African wild dogs.
Even in large, well-protected reserves, or in stable populations remaining largely independent of protected areas, as in northern Botswana, African wild dogs live at low population densities. Predation by lions (Panthera leo), and perhaps competition with spotted hyaenas (Crocuta crocuta), contribute to keeping African wild dog numbers below the level that their prey base could support. Such low population density brings its own problems and are vulnerable to extinction. Problems of small population size will be exacerbated if, as seems likely, small populations occur in small reserves or habitat patches. Animals inhabiting such areas suffer a strong edge effect. Thus, small populations might be expected to suffer disproportionately high mortality as a result of their contact with humans and human activity.
Catastrophic events such as outbreaks of epidemic disease may drive the African wild dog to extinction when larger populations have a greater probability of recovery. Such an event seems to have led to the local extinction of the small African wild dog population in the Serengeti ecosystem on the Kenya-Tanzania border.
Across most of its geographical range, there is minimal utilization of the African wild dog. There is evidence of localized traditional use in Zimbabwe, but this is unlikely to threaten the species’ persistence. There are also some reports of trade in captive and wild-caught animals from southern Africa; the possible impact of such trade is currently being assessed.
• Image | © Fred F, Some Rights Reserved (CC BY-ND 2.0)
• Sources | (Davies & Du Toit, 2004; Kristof, 2010; Mulheisen, Allen, Allen, 2002; Nowak, 1999; Woodroffe & Sillero-Zubiri, 2012)
