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 adjacent to the park. The once-famous "Yosemite Firefall", created by pushing red hot embers off a cliff near Glacier Point at night, was discontinued in the mid-to-late 20th century along with other activities that were deemed to be inconsistent with protection of the national park. Humans may have visited the Yosemite area as long as 8,000 to 10,000 years ago. Habitation of the Yosemite Valley proper can be traced to about 3,000 years ago, when vegetation and game in the region was similar to that present today; the western slopes of the Sierra Nevada had acorns, deer, and salmon, while