In 2010 the National Park Service began to study the link between population declines of desert bighorn sheep and the effects of climate change.
Desert bighorn sheep primarily live in small, isolated herds throughout the mountain ranges of the Sonoran, Mojave, and Great Basin deserts of the southwestern United States. They zigzag up and down cliff faces with incredible ease, using ledges only two inches wide for footholds and bouncing from ledge to ledge over spans as wide as 20 feet. Desert bighorn sheep prefer this steep, rocky terrain for escape from predators, bedding, and lambing.
Climatic variables such as rising temperatures and decreased precipitation affect the availability of vegetation and dependable sources of spring water for this desert species. Water is critical to desert bighorn sheep survival: lactating ewes need to drink almost every day. Animals like desert bighorn sheep also need large areas of land in which to mix herds. Ten national parks are home to the majority of the herds in the National Park Service, and they fulfill a critical role in the conservation of the species.
In 2010 the National Park Service began a collaborative project to study the effects of climate change on desert bighorn sheep, looking in particular at climate refugia and connectivity across the 10 parks. Staff partnered with universities and other government agencies to evaluate the impacts of climate change and identify herds and habitats that are most vulnerable to these changes. NPS staff developed connectivity and network models for the Mojave Desert to prioritize the protection and restoration of habitat patches and dispersal corridors. This analysis provides critical information necessary for NPS staff to comment on renewable energy development plans to encourage the preservation of migration corridors and re-establishment of key populations, two factors that are considered critical to increasing the resilience of the desert bighorn sheep populations in and around national parks in the midst of ongoing climate change.
NPS staff are seeking to maintain and restore populations and corridors of desert bighorn sheep. This direct, on-the-ground management action is one of the best means for offsetting the unpredictable but potentially devastating changes in precipitation and temperature predicted for the American Southwest.