Ecology of California
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The ecology of California can be understood by dividing the state into a number of ecoregions, which contain distinct ecological communities of plants and animals in a contiguous region. The ecoregions of California can be grouped into four major groups: desert ecoregions (such as the Mojave Desert), Mediterranean ecoregions (such as the Central Valley), forested mountains (such as the Sierra Nevada), and coastal forests.<ref>Template:Cite book</ref>
Different authorities define the boundaries of ecoregions somewhat differently: this article follows the definitions of the World Wide Fund for Nature (WWF) and the United States Environmental Protection Agency (EPA)
Deserts
{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} California's high mountains block most moisture from reaching the eastern parts of the state, which are home to California's desert and xeric shrub ecoregions. The low desert of southeastern California is part of the Sonoran Desert ecoregion, which extends into Arizona and parts of northern Mexico.<ref>Template:WWF ecoregion</ref> California has two high deserts: the Mojave Desert and the Great Basin Desert. The Mojave Desert ecoregion is marked by the presence of Joshua trees.<ref>Template:WWF ecoregion</ref> The dry cold Great Basin desert of California consists of the Owens Valley, and is classified into Great Basin shrub steppe by the WWF,<ref>Template:WWF ecoregion</ref> and into the Central Basin and Range ecoregion by the EPA.<ref name=epaMap>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The deserts in California receive between Template:Convert of rain per year.<ref name=ch40>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Plants in these deserts are brush and scrub, adapted to the low rainfall. Common plant species include creosote bush, blackbrush, greasewood, saltbush, big sagebrush, low sagebrush, and shadscale.<ref name=ch40/> Higher elevations have more precipitation, which allows drought-resistant trees to grow, such as western juniper and pinyon pine.<ref name=ch40/>
Mediterranean ecoregions
The coast of California from Monterey Bay south to the Mexican border, and inland from San Francisco Bay Area to the Sierra Nevada foothills contain California's Mediterranean ecoregions. This region is divided by the WWF into three California chaparral and woodlands ecoregions, plus the Central Valley grasslands.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The EPA divides the region between the Central Valley (ecoregion 7), the Southern California chaparral (ecoregion 6), the Southern California mountains (ecoregion 8), and the Southern California coast (ecoregion 85).<ref name=epaMap/>
The WWF distinguishes between different chaparral ecoregions based on species endemism.<ref name=na1201/> In the south, the California coastal sage and chaparral extends across the Mexican border into northwestern Baja California and Los Angeles.<ref name=na1201/> The coastal sage ecoregion is notable for having the highest number of native bees in the United States, although much of the ecoregion is now urbanized.<ref name=na1201/> The California montane chaparral and woodlands include the Transverse Ranges north of Los Angeles as well as the Santa Lucia Range on the Central Coast.<ref name=na1203>Template:WWF ecoregion</ref> The montane chaparral consists of a mosaic of sage scrub, chaparral, and montane species, depending on altitude.<ref name=na1203/> The California interior chaparral and woodlands form a ring around the Central Valley, covering the hills around the Bay Area as well as the foothills of the Sierra Nevada.<ref name=na1202>Template:WWF ecoregion</ref> The interior woodland ecoregion contains several endemic species, due to unique soil types such as serpentine.<ref name=na1203/>
These chaparral ecoregions contain numerous plant communities, including oak savanna,<ref name=na1202/> oak woodland, conifer woodlands, chamise chaparral, coastal sage scrub, and coastal grassland.<ref name=na1201>Template:WWF ecoregion</ref> These plant communities often occur as a mosaic,<ref name=na1203/> caused by fire.<ref>Template:Cite book</ref>
California's Central Valley was once a large temperate grassland containing native bunchgrasses and vernal pools.<ref name=na0801>Template:WWF ecoregion</ref> Grizzly bear, gray wolf, tule elk, and pronghorn antelope used to inhabit the grasslands.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The native grasslands and pools have now been largely replaced by livestock ranches and farms.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Carrizo Plain, where the native grass is preserved, is referred to as the "Serengeti of California".<ref>Template:Cite news</ref>
Forested mountains
The cooler and wetter mountains of northern California are covered by forest ecoregions. Both the WWF and the EPA divide the mountains into three ecoregions: the Sierra Nevada,<ref name=na0527>Template:WWF ecoregion</ref> the Klamath Mountains,<ref name=na0516>Template:WWF ecoregion</ref> and the Eastern Cascades Slopes and Foothills (occurring on the Modoc Plateau).<ref name=na0512>Template:WWF ecoregion</ref>
The Sierra Nevada are home to half of the vascular plant species of California, with 400 species that are endemic to the region.<ref name=na0527/> Like many mountain ranges, the plant communities of the Sierra group into biotic zones by altitude, because of the increasingly harsh climate as elevation increases.<ref>Template:Cite book</ref> These biotic zones include montane forest dominated by conifers such as Jeffrey pine and Lodgepole pine, subalpine forest dominated by whitebark pine, up to alpine tundra which cannot support trees.<ref name=schoenherr>Template:Cite book</ref> The Sierra are also notable for giant sequoia trees: the most massive on earth.<ref>Template:Cite book</ref>
The Klamath and Siskiyou Mountains are a notable biodiversity hotspot, containing one of the four most biodiverse temperate forests in the world.<ref name=na0516/> The diversity is caused by the ecoregion being adjacent to a number of other ecoregions, diverse soil, and having refugia caused by isolation in the last ice age.<ref name=na0516/> Some endemic species in the Klamath mountains are limited to only one mountain or valley.<ref name=na0516/>
The Eastern Cascades slopes of the Modoc Plateau are characterized by a mosaic of open ponderosa pine forest, grasslands, and shrublands.<ref name=na0512/> Although high, these slopes and mountains are in the rain shadow of the Cascade Range, and hence are drier and more open.<ref name=schoenherr/>
Coastal forests
The coast of California north of San Francisco contains the Northern California coastal forests (as defined by the WWF) and the southern section of the Coast Range ecoregion (as defined by the EPA). This ecoregion is dominated by redwood forest, containing the tallest and some of the oldest trees in the world.<ref name=na0519>Template:WWF ecoregion</ref>
The redwood forests thrive in a thin belt up to Template:Convert wide next to the coast, where the trees are kept moist by winter rains and summer fog.<ref name=na0519/> The redwood forests are also notable for having the highest forest productivity in the world.<ref name=na0519/>
See also
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- List of California birds
- Fauna of California
- California Floristic Province
- Geography of California
- California native plants
- Protected areas of California
References
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