Sierra Nevada bighorn sheep (Ovis canadensis sierrae)
The Sierra Nevada Bighorn Sheep was once abundant in its namesake mountains. Well adapted to climbing steep terrain where it can seek cover from predators like coyotes, golden eagles, and cougars, this unique type of bighorn sheep is a denizen of the high country, moving to lower elevations only in the wintertime to feed.
By the early 20th century the animal's numbers were already dropping due to hunting, competition and disease from domestic sheep, and habitat encroachment. The population crashed in the 1980s when it began avoiding its low-elevation winter range. After hitting a low of about 100 individuals, the Sierra Nevada Bighorn was listed as an endangered species in 2000.
Concerted conservation efforts, including putting critical areas off-limits during breeding season, have allowed its numbers to rebound slightly. But the animal now faces shrinking food and water sources due to a host of factors brought on by climate change. Drier, hotter weather, changing precipitation patterns, and a shrinking snow pack have limited the Sierra Nevada Bighorn to five small areas in the southern and central Sierra.
Stretching 400 miles along the eastern edge of the state, California's Sierra Nevada is a lofty north-south spine separating the Great Central Valley from the Great Basin desert. The mountains John Muir called the "Range of Light" reach higher than any others in the continental United States, topping out at 14,505 feet at the summit of Mt. Whitney.
The largest block of exposed granite on earth, the Sierra Nevada's steep eastern face plunges two vertical miles to the desert floor. Its gentler western slopes are laced with glacier-carved canyons, including Yosemite Valley and the even deeper Kings Canyon. These western slopes support one of the most diverse conifer forests in the country, and are home to the world's largest living things: the majestic Giant Sequoia.
Scientists predict that much of the Sierra Nevada's vegetation, including many native plants, may not survive a warming climate. The conifer forests will shrink, worsening the problems as they lose their ability to fight climate change by consuming carbon dioxide. Wildlife already suffering from habitat loss is now contending with water scarcity brought on by global warming. Higher temperatures are steadily reducing the Sierra snowpack, on which not only the Sierra Nevada but most of California relies for its water. More than 60 percent of the water consumed by Californians originates in the Sierra Nevada.
We need to take steps now to ensure that the Sierra Nevada is prepared to deal with the higher temperatures, drought, and other disasters caused by a changing climate. Stopping excessive logging, mining, and unchecked development is a vital first step in sparing the plants and animals of the Sierra Nevada-and the people of California-from the worst effects of climate change. To ensure that our natural systems, and the wildlife that depend upon them, can survive, scientists recommend making the following preparations:
- Protect large blocks of undisturbed habitat, which are called "core areas." These core areas, such as wilderness, national parks, and places planned to preserve nature, provide the most important building block in climate change planning.
- Ensure that there is ample room for wildlife to move between core areas without harm by identifying and protecting corridors between them.
- Protect "buffer areas" by stopping threats such as logging and mining that tear apart the fabric of the natural systems.
The Sierra Club is working to carry out these strategies in the Sierra Nevada mountain range so that its wildlife and natural systems can remain healthy and robust, even as the world around changes. In the process, the Sierra will return the favor by providing us with pure, clean drinking water, a thriving tourism economy, and best of all, an unparalleled wild heritage to pass on to our children and grandchildren. Currently the Sierra Club is working to:
- Improve the Giant Sequoia National Monument management plan by enhancing its protection of the Giant Sequoia groves, ensuring it provides habitat for Pacific fisher and other wildlife, and stopping logging;
- Ensure that the Forest Service creates clear requirements to prepare for changing conditions as they update National Forest Plans in 11 forests in the Sierra Nevada;
Stop clearcut logging on private lands in the foothills of the western side of the range, which is fragmenting the forest and harming key watersheds and wildlife habitat;
- Stop poorly planned urban development from spreading up the west slope of the Sierra.