Plant Communities of California at the ENC
California’s varied topography, climate and soils have given rise to a remarkable diversity of habitats, with a corresponding diversity of both plant and animal species. The ENC showcases representative plants from 15 of California’s plant communities, although it does not come close to representing all of California’s amazing biodiversity!
Geological and climatic forces have created California’s topography and soils. Glaciation, sedimentary and volcanic deposits, movement along fault zones, the uplift of subterranean rock and sediment layers, and gradual erosion have created unique topographical features and an assortment of disparate bedrock and soil types.
California’s extensive range of latitude, along with the varied landscape features, climatic conditions, and geological substrates and soils that exist here has yielded a tremendous diversity of habitats, including alpine meadows, desert scrub, coastal wetlands, sandy beaches, dunes and bluffs, oak woodlands, diverse grasslands, moist redwood forests, spring-fed lakes, and freshwater streams, rivers, and marshes.
The factors that determine where and how a particular plant species grows are:
- Weather, including precipitation, temperature and wind
- Climate, including elevation, humidity, sunlight, heating effects and evaporation rates
- Substrate, including rock and shallow, sandy, loamy or muddy soil
- Local Effects, including fire, soil creep, frozen winter soil and disturbances from burrowing animals and human activities
Plants adapt to combinations of these factors by growing specialized leaves, bark, stem tissues and roots. With its exceptional range of these factors, California has more species than any other state in the US, as well as the greatest number of endemic (existing nowhere else) species. As a result, California is one of the top “hotspots” for biodiversity in the world.
Take a visual tour through the ENC’s Plant Communities
Coastal Sage Scrub
The Coastal Sage Scrub is a plant community typical of Southern California coastal bluffs and canyons. Coastal Sage Scrub is considered by many to be the most endangered plant community in the United States. It has extremely high levels of species diversity and endemism, and it contains a number of endangered species, including the California Gnatcatcher. Coastal Sage Scrub is located on highly valued, coastal real estate and is threatened by development. This ecosystem represents the struggle between preservation and development.
The Coastal Sage Scrub habitat extends from the South Coast Ranges to Baja California, mostly below 3000 feet and below the Chaparral Plant Community. It is characterized by drought adapted shrubs. About 10″ – 20″ of rain falls annually, and that drains quickly through the dry, rocky or gravelly soil. The growing season is 8 – 12 months annually.
Channel Islands Flora
The Channel Islands include 8 islands. Located off the coast of Orange and Los Angeles counties are, south to north, San Clemente, Santa Catalina, Santa Barbara and San Nicholas Islands. Located off the coast of Ventura and Santa Barbara counties are, south to north, Anacapa, Santa Cruz, Santa Rosa and San Miguel. The flora of each island is individual and often quite different than the species found on the mainland. This plant community grows under similar conditions as Coastal Sage Scrub (high humidity) with 15″ – 20″ of rainfall annually.
Chaparral is a Spanish word meaning “where the scrub oak grow.” This plant community is found in semi-arid areas such as the dry slopes and ridges of the Coastal Ranges from Shasta County south, and below the Yellow Pine Forest on the western slopes of the Sierra Nevada Mountains. This habitat is found in the Southern California mountains, as well. Soil here is rocky and gravelly or fairly heavy. Average rainfall is 14″ – 25″ each year. The annual growing season is 8 to 12 months. Brush fires race through this habitat frequently.
Closed Cone Pine Forest
Forests can be divided into two types: hardwood and softwood. Hardwood forests are flower-bearing and softwood forests are coniferous (cone-bearing). Trees that live in the Closed Cone Pine Forest are softwood trees. Plant fossils indicate that closed-cone forests were once widespread but are now remnants on their way to extinction. The average rainfall for this community is 20″ – 60″ annually. Additionally this Central California coastal community receives moisture from fog. The growing season is 9 – 12 months, annually.
Creosote Bush Scrub
Creosote Bush Scrub is a southern California desert plant community. The Mojave and Anza-Borrego areas typify this desert environment. Plant leaves and roots have adapted to withstand intense solar radiation and both extreme cold and extreme heat. Less than 7″ of rain falls annually. This region is very fragile. Paths worn into the soil by travelers at the turn of the century can still be seen today.
Much of California's area is included within the Foothill Habitat, including the foothills of both the coastal and the Sierra Mountains. The soil here is fertile, so wherever water is available, trees and plants flourish. The average rainfall is 15″ – 40″ and the growing season is 6 – 10 months annually.
The Freshwater Marsh is an aquatic community of emersed plants. It is found throughout California where there is permanent standing water. The water table is at or just above the surface. Examples would be the margins of lakes and ponds, ditches, and some extensive shallow marshes such as in the Great Central Valley. The ENC constructed a freshwater marsh in 1998 and 1999.
Mixed Evergreen Forest
Inland from the redwood forest in the Klamath and Coast ranges in Northern California and a partly riparian forest transitional to yellow pine forest in Southern California. Average rainfall is 25″ – 65″ annually, with some fog. The growing season is 7 – 11 months.
Northern Oak Woodlands
This open, grassy woodland is found in the North Coast Ranges, roughly north of the San Francisco Bay to Humbolt County and inland from the redwood forests to 3,000 – 5,000 feet in the Yolla Bolly mountains at the northern extreme of the Sacramento River Valley. Average rainfall is 25″ – 40″, and the growing season is 6 – 9 months annually.
Cretaceous coal deposits contain fossil records of Coast Redwoods looking very much like they do today. Redwoods were once much more widely distributed, however. The remains of a grove have been found in Costa Mesa, California, but today the Redwoods are restricted to a narrow, noncontiguous coastal strip from upper San Luis Obispo County to Brooking, Oregon (just over the California border). This is temperate rainforest with an annual rainfall of 60″ – 140″ and an additional 12″ or so of precipitation in the form of fog drip.
Riparian habitat is the habitat along freshwater rivers and streams, and it exists within all other plant communities where water flows most of the year. Flowing water is much more common in Northern California than in the South, but this habitat is found along the Ortega Highway and the Corona Freeway. In nature, the water table, snow melt and seasonal differences determine the amount of available water in a riparian plant community. The stream at the ENC is run by a recirculating pump and the area is representative of an arroyo riparian community.
South Oak Woodland
The Southern Oak Woodland habitat is located in the foothills below 4,000 feet from the Pasadena region to San Dimas and south to eastern San Diego County. It gets 15 – 25 inches of rain annually, and temperatures are mild to warm. The growing season is 7 – 10 months. Luiseños Native Americans made their lives here, hunting deer and making stone and bone tools. Today, raccoons and coyotes hunt on the ground while Turkey Vultures and Red-Shouldered Hawks patrol above.
This community encompasses a number of perennial bunch grasses as well as many of our common wildflowers. The California Poppy grows here, along with blue-eyed grass, lupines and many plants from the aster family. This habitat is found in the Great Central Valley and the low hot valleys of the inner Coast Ranges such as Antelope Valley, and ascending to about 4,000 feet in the Tehachapi Mountains and eastern San Diego County. The growing season is 7 to 11 months, and 6″ – 20″ of rain falls annually.
Yellow Pine Forest
The Yellow Pine Forest is found throughout California. In the North Coast ranges it is found at elevations of 3000-6000 feet, in Northern California at 1200 – 5000 feet, in the Sierra Nevadas from 2000 – 6500, and in Southern California at elevations of 5000 – 8000 feet. The average rainfall is 25″ – 80″, partly as snow. The growing season is 4 – 7 months.