Chapter 30
Ecological Subregions of the United States

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California Coastal Chaparral Forest and Shrub

Two Sections have been delineated in this Province:

These Sections are located along coastal California. The area of these Sections is about 10,300 mi2 (26,700 km2)

Section 261A--Central California Coast

Geomorphology. This area includes parallel ranges and valleys on folded, faulted and metamorphosed strata; there are rounded crests of subequal height. This Section is in the Coast Ranges geomorphic province. Elevation ranges from sea level to 2,400 ft (0 to 730 m).

Lithology and Stratigraphy. Types include Cenozoic marine and nonmarine sedimentary rocks and alluvial deposits, and Mesozoic granitic and ultramafic rocks.

Soil Taxa. Dominant soils are Alfisols, Entisols, Histisols, Inceptisols, Mollisols, Ultisols, and Vertisols, in combination with isomesic, mesic, or thermic soil temperature regimes and xeric or udic soil moisture regimes.

Potential Natural Vegetation. K\"uchler mapped vegetation as mixed hardwood forest, coastal prairie-scrub, coastal sagebrush, mixed hardwood and redwood forest, redwood forest, and southern oak forest. Predominant potential nautral communities are Coastal Sage (Lucian), Coast Live Oak, Coastal Perennial Grassland and Redwood (northern part) series.

Fauna. This Section includes a variety of coastal, marsh, estuary, wetland, riparian, grassland, shrubland, oak savanna, and broadleaf and conifer forest communities. Mammals include mule deer, bobcat, weasel, fox, skunk, opossum and ground squirrel. Turkey vultures, hawks, owls, herons, egrets, flycatchers, swallows, and ravens are common birds. Birds of concern include the brown pelican, lesser tern, osprey, black rail, clapper rail, marbled murrelet, spotted owl, and bank swallow. Reptiles and amphibians include the western rattlesnake, common and western aquatic garter snakes, northern and southern alligator lizards, and several species of salamanders and frogs. Marine and shore species include sea otter, sea lions, seals, brown pelicans, gulls, cormorants, terns, and various shore birds. Introduced species include small populations of fallow deer and barbary sheep. Feral hogs are common throughout large portions of the Section.

Climate. Precipitation ranges from 14 to 50 in (350 to 1,270 mm). Temperature averages 50 to 63 oF (10 to 17 oC). Summer daytime temperatures often are modified by morning fog and sea breezes. The growing season lasts 200 to 330 days.

Surface Water Characteristics. Several slow moving, tide-affected major rivers in alluvial channels terminate in San Francisco and Monterey Bays. Much of the saltwater marshes on the north and south ends of San Francisco Bay are converted to salt evaporation ponds. A few slow moving perennial streams in alluvial or weak bedrock channels flowing directly to the Pacific Ocean occur in the northern part of the area. Some fast moving perennial streams in weak bedrock channels flowing directly to the Pacific Ocean occur in the southern part of the area. Reservoirs for municipal water supply are common in the northern part of the Section.

Disturbance Regimes. Fires are of variable frequency, season, and intensity. This is a seismically active area with strong shaking and ground rupture.

Land Use. Composition and successional sequence of some plant communities (especially grassland communities) has changed because of plant and animal species introduced between the late 1700's and early 1900's. These changes related to grazing, agriculture, forestry, and urbanization. The northern part is densely urbanized.

Cultural Ecology. Humans have been utilizing the Section for about 8,000 years, and have been an integral part of central coast ecology for about 2,000 years, thriving on the diversity of habitats from ocean and estuary to forest, and intensively gathering numerous resources. The Spanish established missions throughout the area in the late 1700's and early 1800's, introducing agriculture and religious and social changes. Contemporary attitudes and beliefs are varied, often considered liberal or unconventional, particularly in the San Francisco Bay area. The economy is diverse, ranging from San Francisco Bay area financial and computer industries to rural agricultural and fishing industries; shipping, tourism and recreation are important industries.

Compiled by Pacific Southwest Region.

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Section 261B--Southern California Coast

Geomorphology. This Section comprises narrow ranges and broad fault blocks, as well as alluviated lowlands and coastal terraces. It is in the Transverse and Peninsular Ranges geomorphic province. Elevation ranges from sea level to 3,000 ft (0 to 912 m).

Lithology and Stratigraphy. Types include Cenozoic marine and nonmarine sedimantary rocks and alluvial deposits.

Soil Taxa. Soils include Alfisols, Entisols, Inceptisols, Mollisols and Vertisols in combination with thermic and isothermic soil temperature regimes and xeric soil moisture regime.

Potential Natural Vegetation. K\"uchler mapped vegetation as chaparral, coastal sagebrush, southern oak forest and valley oak savanna. Predominant potential natural communities are Coastal Sage (Venturan) and Coastal Perennial Grassland series.

Fauna. This Section includes a variety of coastal, marsh, estuary, wetland, riparian, grassland, shrubland, and oak savanna communities. Mammals include mule deer, coyotes, bobcat, fox, skunk, raccoon, opossum and ground squirrel. Turkey vultures, hawks, jays, quail, owls, herons, egrets, flycatchers, swallows, and ravens are common birds. Birds of concern include the brown pelican, lesser tern, osprey, black rail, clapper rail, California gnatcatcher, and savanna sparrow. Reptiles and amphibians include the western rattlesnake, common garter snake, alligator lizards, and several species of salamanders and frogs. Marine and shore species include sea lions, seals, brown pelicans, gulls, cormorants, terns and various shore birds.

Climate. Precipitation ranges from 10 to 25 in (250 to 640 mm). Temperature averages 61 to 65 oF (16 to 18 oC). Summer daytime temperatures often modified by morning fog and sea breezes. The growing season lasts 250 to 360 days.

Surface Water Characteristics. Very few perennial streams occur in the area. Perennial and intermittent streams occur in alluvial and weak bedrock channels that flow directly to the Pacific Ocean. High velocity and quantity flows periodically occur in the numerous intermittent drainages.

Disturbance Regimes. Historic occurrence of fire has changed from variable frequency, season, and intensity to more frequent, larger, and more intense fires. This Section is a seismically active area with strong shaking and ground rupture. Some plant and animal species are noticeably affected by air pollution.

Land Use. Composition and successional sequence of some communities (especially grassland communities) has changed because of plant and animal species introduced between the late 1700's and early 1900's. These changes related to grazing, agriculture, and urbanization. Most of the area is densely urbanized.

Cultural Ecology. Humans have been utilizing the area for some 8,000 to 10,000 years. People have been an integral part of south coast ecology for 2,000 t0 3,000 years, thriving on the diversity of habitats from ocean and estuary to hills and scrublands, and intensively gathering numerous resources. The Spanish first explored the coastal areas in the mid-1500's; however, they did not establish permanent settlements until the Mission Period, in the late 1700's, thus introducing agriculture and religious and social changes. Widespread urbanization of the Los Angeles basin began in the late 1800's. Contemporary attitudes and beliefs are varied; lifestyle is urban. The international border and large Hispanic populations contribute to cultural diversity. The economy is varied and urban oriented; shipping, fishing, tourism, and recreation are important industries.

Compiled by Pacific Southwest Region.

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