Yosemite National Park is causing the problem. Despite the richness of high-quality habitats in Yosemite, the brown bear, California condor, and least Bell's vireo have become extinct in the park within historical time, and another 37 species currently have special status under either California or federal endangered species legislation. The most serious current threats to Yosemite's wildlife and the ecosystems they occupy include loss of a natural fire regime, exotic species, air pollution, habitat fragmentation, and climate change. On a more local basis, factors such as road kills and the availability of human food have affected some wildlife species. Yosemite National Park has
History of the Yosemite area in pursuit of Ahwaneechees led by Chief Tenaya. Accounts from the battalion, especially from Dr. Lafayette Bunnell, popularized Yosemite Valley as a scenic wonder. In 1864, Yosemite Valley and the Mariposa Grove of giant sequoia trees were transferred from federal to state ownership. Yosemite pioneer Galen Clark became the park's first guardian. Conditions in Yosemite Valley were made more hospitable to people and access to the park was improved in the late 19th century. Naturalist John Muir and others became increasingly alarmed about the excessive exploitation of the area. Their efforts helped establish Yosemite National Park in 1890. Yosemite Valley