Biodiversity and the Sierra Nevada

August 2012

Download National Forests in the Sierra Nevada: A Conservation Strategy.

The Sierra Nevada was recently identified as one the ten places in the U.S. where climate change impacts are the most threatening to endangered species - and where intervention can have the most impact if we act to build resilience back into these biologically vital ecosystems now.

Biological diversity in California's Sierra Nevada is among the highest in the United States. You can read about the region's fabled biodiversity below, and follow the links to the right. You can also read species accounts for a number of important Sierran wildlife species in the column to your left.

willow flycatcherWhat is biodiversity? There are many definitions, but essentially biodiversity is a measure of the variability of living organisms. It may be described in many different ways, but most commonly it is understood as a simple measure of the numbers of different plants and animals that occur within a given geographic region.

Biodiversity may also be described at the molecular, genetic, individual, species, population, and ecosystem levels.

Conservation of biodiversity is not possible without also conserving the ecological and environmental processes and structures that sustain and nurture biological abundance and health.

California is the most biologically diverse state in the nation. It has the greatest number of plant species, and the most endemic species—plants and animals that do not occur anywhere else. It also has the second highest percentage of plant species at risk of extinction. The California Floristic Province, which includes 70 percent of the state including the Sierra Nevada, has been designated as a global biodiversity hotspot by organizations such as Conservation International, the Nature Conservancy and the World Wildlife Fund. Floristic diversity in the California Floristic Province is highest in the Sierra Nevada and Transverse ranges.

The source of this rich biological diversity and high endemism results from plant adaptation and evolution in response to highly varied topography, climate zones, fire regime, geology, and soils found in the Sierra Nevada. The cultural practices of California's first Native Americans also promoted and enhanced biodiversity, helping plants and animals to flourish, particularly through the beneficial uses of fire.

The Sierra Nevada is a landscape dominated by superlatives. It is the source of the continent's tallest mountain, Mt. Whitney at 14,505 feet at the crest of the Sierra, and its great beauty has inspired generations of explorers and naturalists, including the Sierra Club's founder and first conservation advocate John Muir.Giant sequoia

The region contains one of the most biologically diverse temperate conifer forests on the planet, with 26 different species of conifers and over 3,000 vascular plants, 400 of which only occur in the Sierra Nevada. Over 200 plant species are rare, and at least 135 have been designated as  threatened, endangered, or sensitive. Many of these plants are threatened by California's rapid pace of development and multiple sources of habitat loss and degradation.

California also has the richest abundance of varied wildlife species of any state in the U.S., and many of these are found only in the Sierra Nevada. The forests of the region provide a refuge for much of the state's wildlife. The varied topography combined with floristically and structurally diverse plant communities provide a large array of habitats important for maintaining California’s wildlife diversity and abundance.

There are approximately 570 vertebrate wildlife species that inhabit the Sierra Nevada region at
some point in their life cycle, including 290 birds, 135 mammals, 46 reptiles, 37 amphibians,
and 60 fish. Of these, 80 birds, 40 mammals, 10 reptiles, 20 amphibians, and 30 fish are included on the state's Special Animals List. These are animals that are rare; many are listed species and may be threatened with extinction due to loss of habitat. Of these, 26 are endemic to the Sierra Nevada and 26 other species found here are endemic to California, but not restricted to this region. Hundreds of invertebrates, including rare cold stream-dwelling insects, glow-in-the-dark millipedes, show-stopping moths and butterflies, beetles, and old-growth associated snails, are also found here and no where else on the planet.

California's Sierra Nevada is home to the Giant Sequoia, the world's largest tree, as well as the sequoia glowing millipede that glows during spring nights in the duff of the giant trees. New species of Sierran aquatic invertebrates are discovered regularly, joining the growing contingent of rare and endemic species. Fourteen amphibians are only found in the Sierra Nevada, including the rare bejeweled Yosemite toad, now threatened by unregulated grazing in its high mountain meadow habitats. California's state fish, the golden trout, occurs only in two locations, just south of Mt. Whitney. The 11 national forests of the region, comprising approximately 12 million acres of publicly owned lands, are priceless refugia for the region's many and increasingly imperiled wildlife.

Sierra LilyThe native wildlife species found in the Range of Light and the essential habitats that they depend upon for their continued survival continue to be at risk from the activities and ill-conceived decisions of some of their human neighbors. Lack of ecological knowledge and understanding about the species which share our earth home—and the continuous pressure to exploit our natural resources—threaten to erode the traditional values and bedrock environmental protections that have preserved the Sierra's rich biological legacy.

It is imperative that wildlife species have a voice which speaks on behalf of their needs—and against the threats posed to them. The continued loss and degradation of the core habitat for many of these species is the central reason why certain projects and plans are fought so adamantly by Sierra Forest Legacy and our team of scientific and legal experts, with the help of our grassroots advocates.

Within this section, check the panel on the right for references and websites devoted to biodiversity studies and literature. In the panel at left, you can link to information about some of the wildlife that are the most at risk, and those we are working to protect throughout the Sierra Nevada. There is also a link to an analysis of the U.S. Forest Service Management Indicator Species program—a robust scientific monitoring program which has never been implemented. Regular population monitoring of wildlife is an essential and basic wildlife management tool, necessary to understand the impacts of management decisions and activities, and the responses of wildlife to changes in their habitats.

Please support our efforts to secure a lasting protection for the Sierra Nevada's marvelous legacy of biodiversity. Please donate to help us continue this important work, sign up for our newsletter and action alerts, or give us a call. We'd love to hear from you.


"The last word in ignorance is the man who says of an animal or plant: "What good is it?" If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering."

"A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it does otherwise."

~Aldo Leopold