Forces of Change for Wildlife in Yosemite National Park

Courtesy Santa Cruz Predator Bird Research Group

Keay, J. A. 1991. Forces of change for wildlife in Yosemite National Park. Page 304 in J. Edelbrock and S. Carpenter (eds). Natural Areas and Yosemite: Prospects 2for the Future. U. S. National Park Service, Denver Service Center, Denver, CO.

ABSTRACT: Several sources of human activities affect the natural integrity of wildlife populations in Yosemite National Park. They occurred 1) historically, 2) within the park, 3) across political boundaries, and 4) in distant locations. The park has four ongoing wildlife management programs that demonstrate the variety and types of those pressures and provide a perspective of the types of forces yet to affect the park. Hunting and domestic sheep grazing eliminated bighorn sheep from the central Sierra Nevada Mountains by the late 1800s, including what is now Yosemite National Park. Failure of remnant populations to expand naturally promulgated the reintroduction of bighorn sheep in 1986. Open-pit garbage dumps associated with human developments and increasing visitation within the park in the 1920s attracted bears, resulting in personal injuries and property damage to humans and altered food habits, habitat use patterns, movements, distribution, reproductive rates, and presumably abundance of bears. A comprehensive management program was implemented in 1975 to restore the natural integrity of the black bear population and protect visitors and their property. The park supports a large deer herd but contains essentially no winter range. Deer cross the park boundary in fall and are hunted, which alters herd sex and age ratios. Deer winter on public land where timber harvest, livestock grazing, mining, and recreation are among the important multiple-use activities. Habitat loss occurs on private land that is increasingly used for homesite development as foothill communities serve retirees and commuters to Central Valley and Bay Area cities. Peregrine falcons continue to suffer from pesticide poisoning that originates from agricultural practices in California and Central and South America. Managers must look beyond unit boundaries for opportunities to affect decisions that could have consequences to the integrity of natural area plant and animal communities. Building effective relationships with other governmental agencies through cooperative conservation and education programs will foster goodwill and allow opportunities for objective input. Wildlife management and research projects in Yosemite provide unique opportunities to gather information of value to animal population restoration efforts in other states, countries, and continents. Black bear research has provided important population dynamics information that will be valuable to conservation efforts for other bear species.