Evaluating the benefit of captive breeding and reintroductions to endangered Sonoran pronghorn

Sonoran pronghorn (Antilocapra americana sonoriensis), an endangered subspecies of American pronghorn, are of great conservation concern in the southwestern U. S. Following a dramatic population decline in 2002, the U.S. Fish and Wildlife Service (USFWS) began a captive breeding program that has subsequently been used to supplement the wild population. Additionally, in 2009 the USFWS proposed to establish another, self-sustaining population outside of their range at that time. We modeled Sonoran pronghorn population dynamics based on time-series of abundance and conducted a population viability analysis (PVA) to evaluate the benefit of these management actions. We found that rates of change in the Sonoran pronghorn population were closely tied to the amount of precipitation in the area but that viability was greatly enhanced by conservation actions including the maintenance of a captive population, as well as the establishment of two additional populations outside the current range.