Epidemiology of Coyote Introgression into the Red Wolf Genome

Abstract

Extensive predator control programs and habitat alterations reduced red wolves, once native to the southeastern United States, to a remnant population found in only a small portion of their historic range by the late 1960's. Coyotes expanded their range into territories previously occupied by red wolves. As wolves became scarce, they began to breed with the more prevalent coyote. Introgression threatened the continued existence of the genetic integrity of the red wolf. The U.S. Fish and Wildlife Service, following a planned extirpation and institution of a captive breeding program, reintroduced red wolves to northeastern North Carolina in 1987. Though surveys had shown no evidence of coyotes in the reintroduction area, coyotes expanded their range eastward and a small red wolf population again interfaced with an increasing coyote population. The movement of introgression within the red wolf population is akin to the movement of an infectious disease. Identification of "infected" and "non-infected" individuals is accomplished at an early age in this population through pup assessments in the den. Intervention is accomplished through the use of sterilized coyotes and coyote-wolf hybrids to prevent the spread of the "disease" to "susceptible" individuals. Understanding how the "disease" moves through the population by describing movement rates and the potential for contact between "infected" and "susceptible" individuals is accomplished through the analysis of telemetry locations of radiocollared individuals. The model for this "disease" is also presented and evaluated to determine the effectiveness of intervention strategies in controlling the spread of this "disease".