Ecology of California - Mediterranean Ecoregions

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. 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).

The WWF distinguishes between different chaparral ecoregions based on species endemism. In the south, the California coastal sage and chaparral extends across the Mexican border into northwestern Baja California and Los Angeles. 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. 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. The montane chaparral consists of a mosaic of sage scrub, chaparral, and montane species, depending on altitude. 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. The interior woodland ecoregion contains several endemic species, due to unique soil types such as serpentine.

These chaparral ecoregions contain numerous plant communities, including oak savanna, oak woodland, conifer woodlands, chamise chaparral, coastal sage scrub, and coastal grassland. These plant communities often occur as a mosaic, caused by fire.

California's Central Valley was once a large temperate grassland containing native bunchgrasses and vernal pools. Grizzly bear, gray wolf, tule elk, and pronghorn antelope used to inhabit the grasslands. The native grasslands and pools have now been largely replaced by livestock ranches and farms. The Carrizo Plain, where the native grass is preserved, is referred to as the "Serengeti of California".