RAD decisions in rad landscapes: Climate adaptation for Sonoran pronghorn

Abstract

The federally endangered Sonoran pronghorn (Antilocapra americana sonoriensis; herein, pronghorn) is endemic to arid desert landscapes in the southwestern United States (U.S.) and northwestern Mexico. Historically, the range of Sonoran pronghorn in the U.S. extended east from the Salton Sea in California to Tucson and Nogales in Arizona and extended south from the Salton Sea and Phoenix, Arizona, to the border with Mexico (Phelps and Webb 1981, Krausman et al. 2005). Factors that contributed to the decline of pronghorn include habitat fragmentation, livestock grazing, and historical unregulated hunting. More recently, prolonged drought has been linked to severe acute mortality events. In 2002, the pronghorn population in the U.S. declined to just 21 individuals. To support species recovery, managers have implemented a range of intensive management actions such as construction of water storage tanks and drinkers (herein, guzzlers), captive breeding, translocation, provision of supplemental feed, and irrigation of forage (USFWS 2016). All active management in the U.S. is concentrated in southwest Arizona, which includes the endangered population of pronghorn in the Cabeza Prieta National Wildlife Refuge (NWR) and two non-essential experimental populations in the Kofa and the Sauceda management units (Section 10(j), Endangered Species Act; Box 1). Current recovery activities have been successful in reversing population decline over the past two decades. Nevertheless, climate change poses a significant threat to long-term species persistence.

Citation

Hefty, Kira; Rushing, Jaclyn Fox; Zeller, Katherine; Schmidt, Greta; Bright, Jill; Sitzmann, Paul; Wilkening, Jennifer; Fuest, Stephanie. 2025. RAD decisions in rad landscapes: Climate adaptation for Sonoran pronghorn. Final Report. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Aldo Leopold Wilderness Research Institute. 101 p.