California Floristic Province

The California Floristic Province (CFP) is a floristic province with mediterranean climate located on the Pacific Coast of North America with a distinctive flora that bears similarities to floras found in other regions experiencing a winter rainfall, summer drought climate like the Mediterranean Basin. It belongs to the Madrean Region of the Holarctic Kingdom. With an area of 293,804 km² , as defined by Conservation International, it includes 70% of California and extends into southwestern Oregon, a small part of western Nevada and northern Baja California. The province is bordered by the Rocky Mountain Region in the north. The boundary is vague and is not well-defined. Many leading geobotanists, including Robert F. Thorne (Flora of North America) and Armen Takhtajan, include Oregon and Northern California within the Rocky Mountain Province. The California Floristic Province is a world biodiversity hotspot as defined by Conservation International, due to an unusually high concentration of endemic plants: approximately 8,000 plant species in the geographic region, and over 3,400 taxa limited to the CFP proper.

Climate and topography

The California Floristic Province is one of the five biodiversity hotspots with Mediterranean climates, and it is characterized by hot, dry summers and cool, wet winters.

In California, the province includes most of the state excluding the Modoc Plateau, Great Basin and deserts in the southeastern part of the state. In Oregon, the province includes the coastal mountains south of Cape Blanco and most of the Rogue River watershed. In Baja California, the province includes the forest and chaparral belts of the Sierra Juarez and the Sierra San Pedro Martir (but excluding their desert slopes to the east), coastal areas south to about El Rosario, and Guadalupe Island. In Nevada, the CFP includes the region of the Sierra in the vicinity of Lake Tahoe, with the eastern border with the Great Basin corresponding roughly to the location of Reno-Carson City.

Parts of the following mountain ranges are included in the province:

• The Klamath Mountains
• The Cascade Range
• The Coast Ranges
• The Sierra Nevada
• The Transverse Ranges
• The Peninsular ranges south into Baja California

The Great Central Valley is also within the CFP.

California Plant Communities

Numerous plant communities exist in California and botanists have attempted to structure them into identifiable vegitation types groupings. Robert Ornduff and colleagues Phyllis M. Faber and Todd Keeler-Wolf did much work on this problem, and in the 2003 Natural History Guide Introduction to California Plant Life established a cohesive set of titles to identify California plant communities based on but somewhat different from those earlier established by California botanist Philip A. Munz.

Broken into three large groupings based on geography, the Ornduff scheme includes: the Cismontane (west of the Sierra Nevada), Montane and Transmontane regions (East of the Sierra crest and the Deserts).

The Cismontane Region

• Coastal Strand (same in Munz)
• Coastal Prairie (same in Munz)
• Coastal Salt Marsh (same in Munz)
• Chaparral (Hard Chaparral) (same in Munz)
• Closed-Cone Pine Forest (same in Munz)
• Coastal Sage Scrub (Soft Chapparal) (same in Munz)
• Freshwater Marsh (same in Munz)
• Maritime Coast Range Ponderosa Pine forests
• Montane Chaparral (not in Munz)
• North Coastal Forest (includes North Coastal Coniferous Forest, Redwood Forest, Douglas-fir Forest and Mixed Evergreen Forest (from Munz)
• Northern Coastal Scrub (same in Munz)
• Riparian Woodland (same in Munz)
• Valley and Foothill Woodland (includes Northern, Southern Oak Woodland, Foothill Woodland)
• Valley Grassland (same in Munz)

Montane Region

• Montane Coniferous Forest (Yellow Pine in Munz)
• Montane Chaparral (not in Munz)
• Subalpine Forest (Red Fir Forest, Lodgepole Pine Forest, Bristlecone Pine and Subalpine Forest)
• Montane Meadow (not in Munz)
• Alpine Fell-field (same in Munz)

Transmontane Region

• Pinyon-Juniper Woodland (Includes Northern Juniper Woodland, Pinyon-Juniper Woodland (both in Munz))
• Sagebrush Scrub (same in Munz)
• Shadscale Scrub (same in Munz)
• Alkali Sink Scrub (same in Munz)
• Joshua Tree Woodland (same in Munz)
• Creosote Bush Woodland (same in Munz)

Flora

The hotspot presents a higher level of endemism in plants than in animals. Of the 3,500 vascular plants found in the hotspot, 2,124 species (in 52 genera) are endemic, meaning they are found nowhere else. About 80,000 km², or 24.7% of the original vegetation remains in relatively pristine conditions today.

The province notably has giant sequoia forests, oak woodlands and redwood forests. Other ecosystems include sagebrush steppes, prickly pear shrublands, coastal sage scrub, chaparral, juniper-pine woodland, upper montane-subalpine forests, alpine forests, riparian forests, cypress forests, mixed evergreen forests, and Douglas fir forests, coastal dunes, mudflats and salt marshes.

A few examples of plants that are endemic to the province and are also endangered species are:

• Baker's larkspur
• Gowen cypress
• Hickman's potentilla
• Point Reyes birdsbeak
• Santa Cruz Tarplant
• Santa Rosa Island Manzanita

Fauna

Of the 150 native mammals, 20 are endemic, including the Salt Marsh Harvest Mouse, Giant Kangaroo Rat, the San Joaquin Kit Fox and the Island Fox.

Out of 340 recorded bird species, 5 are endemic, including the critically endangered California condor. This is the United States' largest avian breeding ground. Other endangered avafauna are the California clapper rail and the California least tern.

The province is home to 70 reptile species, 4 of which are endemic.

More than half of the 50 native amphibian species are endemic, including the Santa Cruz Long-toed Salamander and the desert slender salamander. About 70 species of freshwater fish are represented.

There are numerous endemic insects including the San Bruno elfin butterfly and Smith's blue butterfly.

Threat

Agriculture and urban expansion are encroaching upon remaining habitat in the CFP. Commercial farming in the region generates half of all agricultural products consumed by Americans. Other threats include air pollution, soil contamination and road construction.

References

• Ornduff, R., Faber, P. M. & Keeler-Wolf, T. 2003. Introduction to California Plant Life. Revised edition. University of California Press
• California Floristic Province, Smithsonian National Museum of Natural History
• California Floristic Province, Biodiversity Hotspots, Conservation International