Sierra Nevada Coniferous Forests

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Monarch butterfly (Danaus plexippus), California, United States of America.
© WWF / Hannes STRAGER

About the Area

The Sierra Nevada ecoregion harbors one of the most diverse temperate conifer forests on Earth, displaying an extraordinary range of habitat types and supporting many unusual species. They are home to an enviable variety of conifers including the Giant sequoia (Sequoiadendron gigantea). Giant sequoias are the largest trees on Earth in terms of total volume, with some trees 83 meters (273 ft) tall, over 10 meters (36 ft) in diameter, and over 3,200 years old.

Most conifers here are adapted to a climate of cool, wet winters and warm, dry summers. Other conifer species, such as ponderosa pine, are more tolerant of hot, dry ridges, while species such as Jeffrey pine dominate the Sierra Nevada’s' eastern slopes where colder, drier winters are the norm.

Four National Parks, Lassen, Yosemite, Sequoia, and Kings Canyon, and some National Forest Wilderness Areas, harbor the largest remaining blocks of relatively intact montane mixed conifer forests.
Size:
53,000 sq. km (21,000 sq. miles)

Habitat type:
Temperate Coniferous Forests

Geographic Location:
Western United States

Conservation Status:
Critical/Endangered
Local Species
50% of California s estimated 7,000 species of vascular plants occur in the Sierra Nevada, with 400 Sierra endemics and 200 rare species.

Approximately 400 terrestrial vertebrate species occur in the Sierra Nevada, 13 are endemic to the range. Found here are the white-headed woodpecker (Picoides albolarvatus), Sierra green sulfur butterfly (Colias behrii), Yosemite toad (Bufo canorus), Mount Lyell salamander (Hydromantes platycephalus), the threatened limestone salamander (H. brunus), Clark's nutcracker (Nucifraga columbiana), mountain lion (Felis concolor), sugar pine (Pinus lambertiana), and Ponderosa pine (P. ponderosa).

The Sierra’s support a diverse invertebrate fauna with a number of endemics, including Behr’s colias butterfly (Colias behrii), restricted to a small area around Tioga Pass.
 / ©: WWF-Canon / Edward PARKER
Giant redwood (Sequoiadendron giganteum), Sequoia National Park, California, United States of America.
© WWF-Canon / Edward PARKER

Featured species

Yosemite Toads (Bufo canorus) are small olive green toads with black spotting, endemic to the Sierra Nevada Mountains. It measures 4.5 – 7 cm. It is robust and stocky with dry, uniformly warty skin. Eyes are closely set and pupils are horizontal. Dorsal stripe is very faint or absent. Males are pale yellowish green or olive above, with few or no dark blotches. Females and young are heavily blotched on a light background. Throat and belly is pale on both sexes.

Diet consists of a wide variety of invertebrates. Typical of most frogs, the prey is located by vision, and then a large sticky tongue is used to catch the prey. It moves by walking instead of hopping. It is active in daytime, usually in sunny areas. It shelters in burrows and in clumps of vegetation near water. Its primary habitat consists of ponds used as breeding areas and nearby meadows that provide food.

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Threats
A century of intensive logging, mining, railroad building, development, fire suppression, and grazing by sheep and cattle have left only around 25% intact natural habitat in the Sierra Nevada. One third of the original extent of Giant Sequoia groves has been harvested.

Other problems include forest simplification, removal of older trees with their structural and genetic resistance, loss of natural firebreaks such old growth patches with sparse understories and moist riparian vegetation, replanting schemes using genetically-similar seedlings of a single tree species, and intensive application of pesticides that also destroys natural predators on epizootics.
WWF’s work
WWF’s Global Forest Programme works to conserve the world’s forests. WWF aims to protect the most significant and threatened forests, ensure they are monitored and properly managed, guarantee that their ecological integrity is enhanced, and that they are increasingly self-sustaining.

Nearly 50% of the world’s original forests have been lost, and many are still being damaged or destroyed. This means the loss of habitat for plants and animals, as well as vital resources for communities. WWF seeks to reverse the loss and degradation of forests, and restore their ecological role and function.

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