Yosemite National Park Nature

Natural Resources at Yosemite National Park

Yosemite National Park is located in the central Sierra Nevada of California and lies 150 miles east of San Francisco and only a six hour drive from Los Angeles. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, giant sequoia groves, and biological diversity. The 750,000-acre, 1,200 square-mile park contains thousands of lakes and ponds, 1600 miles of streams, 800 miles of hiking trails, and 350 miles of roads. Two federally designated wild and scenic rivers, the Merced and Tuolumne, begin within Yosemite's borders and flow west into California's Central Valley. Annual park visitation exceeds 3.5 million, with most visitor use concentrated in the seven square mile area of Yosemite Valley. View of Half Dome from Glacier Point. From the Yosemite Valley Floor at an elevation of 4,000 feet, the magnificent cliffs such as El Capitan and Half Dome rise 3,000 to 4,000 feet higher to forested uplands on either side.

The geology of Yosemite is characterized by granitic rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode. The downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today.

Yosemite is one of the largest and least-fragmented habitat blocks in the Sierra Nevada, and it supports a diversity of plants and wildlife. The park has an elevation range from 2,000 to 13,123 feet and contains five major vegetation zones: chaparral/oak woodland, lower montane, upper montane, subalpine and alpine. Of California's 7,000 plant species, about 50% occur in the Sierra Nevada and more than 20% within Yosemite. There is suitable habitat or documented records for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.

Yosemite has more than 300 species of vertebrate animals, and 85 of these are native mammals. Black bears are abundant in the park, and are often involved in conflicts with humans that result in property damage and, occasionally, injuries to humans. Visitor education and bear management efforts have reduced the bear-human incidents and property damage by 90% in the past few years. Ungulates include large numbers of mule deer. Bighorn sheep formerly populated the Sierra crest, but have been reduced to several remnant populations. There are 17 species of bats, 9 of which are either Federal or California Species of Special Concern. Over 150 species of birds regularly occur in the parks. Great gray owls are of special interest in Yosemite because here they reach the furthest southern extent of their global range, and they are isolated by hundreds of miles from the next closest population in far northern California.

Threats to park resources and the integrity of park ecosystems include loss of natural fire regimes, air pollutants and air-borne contaminants, global climate change, direct impacts to resources from high visitation in some areas of the park, habitat fragmentation from both outside and inside park boundaries, and the invasion of non-native plant and animal species. The park is actively attempting to control the non-native plant species that pose the most serious threat, such as spotted knapweed, yellow star-thistle, bull thistle, and Himalayan blackberry. The presence of wild turkeys, white-tailed ptarmigan, bullfrogs, introduced fish and other non-native animal species in Yosemite threaten the park's native species.

The park's 1980 General Management Plan outlines the purpose, goals, and objectives of Yosemite National Park. The plan gives two primary purposes for Yosemite National Park. The first is preservation of the resources that contribute to Yosemite's uniqueness and attractiveness - its exquisite scenic beauty; outstanding wilderness values; a nearly full representation of Sierra Nevada environments, including rare and beautiful sequoia groves; the granite domes, valleys, polished granites, and other evidence of the geologic processes that formed the Sierra Nevada; historic resources, especially those related to the beginnings of a national conservation ethic; and prehistoric evidence of the Indians who lived on the land for thousands of years. The second purpose is to make the varied resources of Yosemite available to people for their enjoyment, education, and recreation, now and in the future.

Goals given in the park's General Management Plan include: Reclaim Priceless Natural Beauty Markedly Reduce Traffic Congestion Allow Natural Processes to Prevail Reduce Crowding Promote Visitor Understanding and Enjoyment

You may learn more about Yosemite's Natural Resources Management program and the resources themselves by visiting the web page links to individual program areas posted at the top of this page.

Additional Nature and Science Topics for Yosemite

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