Sierra Nevada Region, California, USA
Hugging the eastern edge of California, the 650 kilometer long Sierra Nevada mountain range soars to the summits of snowy peaks and falls into countless crystal-clear alpine lakes. Visitors from around the world wind their way through glacially-scoured canyons such as Yosemite Valley and explore natural wonders such as Lake Tahoe and Mount Whitney, resting beneath ancient groves of giant sequoias. This spectacular scenery is also quietly hard at work securing the health and welfare of California’s 30 million residents.
A vital component of the state’s economy, the Sierra Nevada ecosystem produces approximately $2.2 billion worth of commodities and services annually, by providing substantial water resources, agricultural and timber products, ranching, mining, tourism, and recreation. Water accounts for more than 60 percent of the total value of commodities and services or more than $1.32 billion. The region’s numerous rivers, hundreds of lakes and thousands of miles of streams yield 65 percent of California’s developed urban and rural water supply and nearly all of the water for western Nevada.
As California’s principal watershed, the region is the critical source of water for urban and rural parts of northern and southern California, thereby supporting the 5th largest economy in the world. Carbon sequestration is likely to play an increasingly important role in this forested region’s economy as the California legislature passed into law in September of 2006 an aggressive target of reducing the state’s greenhouse gas emissions to the 1990 levels by the year 2020.
The Sierra hosts some of the world’s most notable natural features including Yosemite Valley, Lake Tahoe, Mono Lake, and Giant Sequoia groves which attract millions of tourists each year. Recreational activities account for more than 50 million recreational visitor days per year. The Sierra Nevada Mountain range supports wilderness backpackers, skiers, fishermen, and hunting enthusiasts, off-road vehicle users, naturalists, and many others.
While the region provides ample resources, care is warranted in managing these resources to ensure their persistence into the future. Many threats to the region’s ecosystem exist. Dams and diversions throughout most of the Sierra Nevada have profoundly altered stream-flow patterns and water temperatures, with significant impacts to aquatic biodiversity. Anadromous fish (Chinook salmon, steelhead), once native to most major rivers north of the Kings River, are now nearly extinct from these rivers. Additionally, amphibian species at all elevations have severely declined throughout the Sierra Nevada. Imperiled species include: bighorn mountain sheep, Yosemite toad, foothill yellow-legged frog, mountain yellow-legged frog, western pond turtle, California horned lizard, willow flycatcher, and olive-sided flycatcher.
By 2040, almost 20 percent of the Sierra’s current private forests and rangelands could be affected by projected development. Over the past forty years, nearly 800,000 acres of oak woodlands have been converted to other land uses and vegetation types with the major losses since 1973 due to conversions to residential and industrial developments. This shift represents the largest threat to the continued sustainability of ecological functions in the Sierra. Additionally, nearly 70 percent of the region's forests and rangelands are ecologically at risk from wildfire.
Climate change also presents significant potential impacts to the Sierra's life-support systems. Increased temperatures threaten to greatly reduce the Sierra snowpack, thereby diminishing the state's primary source of water.
In The News
California’s Historic Ranching Culture at Significant Risk from Climate Change
“The Nature Conservancy today released ‘The Impact of Climate Change on California's Environmental Services’ as part of the California Climate Action Team's Draft Biennial Report, a multi-faceted study that highlights how climate change will impact California's economy, residents and our natural areas...The Conservancy co-authored a chapter in the study focusing on impacts to California’s key economic sectors that rely on nature including ranching, skiing, salmon fishing and emerging carbon markets...‘We can't wait to address the threats climate change poses, and we must take steps to ensure that California's economy and way of life not only survive, but ultimately prosper,’ said [Rebecca] Shaw. ‘In addition to reducing greenhouse gas emissions, we must also identify and fund solutions that can help our natural areas, communities and industries remain viable in the face of climate change.’”