[2] There are many hiking trails, paved and unpaved roads, and vast public lands in the Sierra Nevada for exploring the many different biomes and ecosystems.

[3] The western and eastern Sierra Nevada have substantially different species of plants and animals, because the east lies in the rain shadow of the crest.

[6] Animals typical of this zone include black bear, ringtail cat, coyote, gray squirrel, bobcat, California mule deer, and skunk.

[4] In the foothills of the northern portion of the Sierra Nevada, toyon and chamise often co-dominate certain open serpentine chaparral communities.

[7] Beginning near the 3,000-foot (900 m) elevation, the hot, dry summers and cool, moist winters of the Mediterranean climate give rise to the lower montane forest zone.

[4] The lower montane forests also include trees such as California black oak, sugar pine, incense-cedar, and white fir.

[3] Animals that may be found in this zone include the dark-eyed junco, mountain chickadee, western gray squirrel, mule deer, and American black bear.

[3] Common animals in this zone include the hermit thrush, dusky grouse (Dendragapus obscurus), great grey owl, golden-mantled ground squirrel, and (more rarely) the marten.

[13][14] Some animal species that are adapted to this zone include the American pika, Belding's ground squirrel, the yellow-bellied marmot, and the endangered Sierra Nevada bighorn sheep.

Natural and human-caused disturbances, such as wildland fires and construction activities, have contributed to a rapid increase in the spread of non-native plants.

A number of these species aggressively invade and displace the native plant communities, resulting in impacts on the park's resources.

Many non-native species, such as yellow starthistle (Centaurea solstitialis), are able to produce a long tap root that allows them to out-compete the native plants for available water.

[15] Bull thistle (Cirsium vulgare), common mullein (Verbascum thapsus), and Klamath weed (Hypericum perforatum) have been identified as noxious pests in Yosemite since the 1940s.

Additional species that have been recognized more recently as aggressive and requiring control are yellow starthistle, sweet clovers (Melilotus spp.

Annual monitoring of lodgepole needle miner density began in 1966, and 28 permanent plots are scattered north of the Cathedral Range.

The current outbreak began in 1973 and has been sweeping around the south side of the Cathedral Range, arriving at Sunrise High Sierra Camp in 2001.

Thus, fire suppression activities are thought to have had little influence upon species composition, structure, fuels, and natural processes in lodgepole forests.

All three types of wetlands provide rich habitat for plant and animal species, delay and store seasonal floodwaters, minimize downstream erosion, and improve water quality.

When inundated, riverine wetlands provide habitat for water-tolerant plants such as willows, and aquatic animals such as tadpoles and immature fish.

[26] Lacustrine wetlands generally occur on river floodplains and along lakeshores and are influenced by seasonal variations in groundwater levels.

[26] Palustrine wetlands are typically distinguished from riverine and lacustrine systems by the presence of very dense covers of trees, shrubs, or emergent plants.

[26] In 1996 the United States Fish and Wildlife Service delineated and classified some of the wetlands of the Sierra Nevada, including all of Yosemite National Park.

This was performed through an analysis of aerial photographs and topographic maps, as a part of the National Wetlands Inventory Web Site (NWI).

These actions are currently being monitored with vegetation transects and mapping of surface water to determine how successful the project was in restoring the wetland.