The relationship between science and management in recovery of the endangered island fox (Urocyon littoralis)

Although recovery programs for endangered species should be informed by science, the lack of knowledge about some species can make implementation of recovery actions difficult. On the other hand, designation of endangered status can focus attention on a species and facilitate allocation of basic and applied research efforts. This is illustrated in the case of the island fox (Urocyon littoralis), in which 4 of 6 subspecies declined precipitously in the 1990s and were subsequently listed as endangered by the U.S. Fish and Wildlife Service. Ecological monitoring and research discovered the fox population declines and the underlying causes (canine distemper virus and golden eagle [Aquila chrysaetos] predation), as well as the altered trophic relationships induced by non-native ungulates that contributed indirectly to 3 of the population declines. These discoveries led logically to the emergency recovery actions of golden eagle removal, island fox captive breeding, and vaccination of foxes against canine distemper virus, but also to support for larger ecosystem-wide actions: removal of non-native ungulates and restoration of bald eagles (Haliaeetus leucocephalus). Captive breeding of island foxes had not been previously attempted, but was informed by demographic modeling and the extensive genetic research that had been previously conducted on the species. Lack of knowledge about island fox reproductive biology hampered captive breeding success, though current research is beginning to close that gap. Intense veterinary and post-mortem scrutiny of captive and released foxes has led to a wealth of knowledge about island fox diseases, parasites and mortality factors. In combination with intense monitoring of captive and released foxes, the research has allowed managers to make informed recovery decisions, resulting in removal of the extinction threat, as well as incipient recovery of the listed subspecies.