California Floristic Province
Americas, Hotspots

From giant sequoias to coastal dunes and marshes, the California Floristic Province brags exceptionally high plant diversity and varieties of habitat. It is the only hotspot that occurs largely within the borders of the United States. It is also within the most populated and fastest growing and one of the most ecologically degraded states in the U.S.- California.

Stretching along the west coast starting in southwestern Oregon, it covers 70% of the State of California, and into northwestern Baja California, Mexico. The iconic Cascade and Sierra Nevada ranges teeming with seasonal wildflower displays are included within this hotspot’s boundaries, as are the Channel Islands off California’s southwestern coast and Isla Guadalupe west of Baja California.


The California Floristic Province is a unique mixture of northern temperate and arid southern regions in a climate of hot, dry summers and cool, wet winters. Four other hotspots share this Mediterranean climate: Central Chile, the Cape Florisitc Region of Africa, Southwestern Australia, and the Mediterranean Basin.

Four regions within the hotspot have exceptional plant diversity: the Sierra Nevada, Transverse Ranges, Klamath-Siskiyou region, and Coast Ranges. The southern Sierra Nevada is home to the giant sequoia trees believed to be the largest species that ever lived. 10 rare plant communities have been recorded in the Transverse Ranges. The Klamath-Siskiyou area is home to around 20 rare plant communities including the most diverse temperate coniferous tree community in the world. The Coast Ranges include a wide variety of habitats, coastal dunes, salt marshes, chaparral, cypress forests, redwood forests, prairie scrub, and fresh water marshes. The unusual plant diversity combined with human’s preference to live in lowland coastal areas puts these regions at great risk.

In total, the Province is host to an incredible 3,488 native plant species, 2,124 of which are endemic.

Also noteworthy are the high number of the region’s endemic amphibians, particularly the salamanders including the arboreal salamanders which climb to the top of the tallest redwoods.

The grizzly bear no longer roams the region, the last one was shot in 1920s. However, the California Condor, the largest bird in North America is regaining ground in the wild after collaborative conservation efforts brought it back from the brink of extinction. Two elk species are also native to the Province, as are foxes, rare mice, mountain lions, and brown bears.


The Province is host to both Mexican and U.S. culture with the unique flavor of California strongly influencing the region and the culture of the U.S. as a whole. California often plays the role of driver of consumer culture in the U.S., representing the fulfillment of the American dream as portrayed in Hollywood films. It’s milder climate also positions it as the main agricultural and culinary center, integrating foods, languages, and traditions from all over the world.

The laid-back lifestyle of southern beach towns, and differently, the northern forest dwellers, juxtapose with the southern Hollywood and entrepreneurial San Franciscans that drive consumer culture. Like most places in the world, it is a land of paradoxes.

Busy California commercial farmers produce over half of all agricultural products consumed in the U.S.


As the most populated and fastest growing state in the U.S., the region’s biodiversity is severely threatened by human pressures. Urbanization, air pollution, agricultural expansion, logging, strip mining, oil extraction, road construction, livestock grazing, invasive species, the use of off-road vehicles, and fire suppression all pose significant threats to biodiversity. The current and future impacts of climate change are still unfolding across the region and earth. Saltwater and freshwater wetlands have declined by about 90% due to land-filling for development.

Scientists estimate that no more than 25% of the California Floristic Province remains in pristine condition.


California has a long history of conservation, being the state that gave rise to the Sierra Club out of John Muir’s experiences in the Sierra Nevada range. Yosemite, Sequoia, Redwood, and Channel Islands National Parks offer protection for the region’s unique biodiversity. Yet protected areas still only account for 37% of the hotspot.

Even in a land of extreme wealth and resource compared to developing tropical nations, a great deal still needs to be done to ensure adequate protection for this hotspot’s biodiversity.

The Sierra Club, Wilderness Society, Nature Conservancy, Conservation International, and California Native Plant Society all are major contributors to conservation efforts in the California Floristic Province.


Russell Mittermeier, et al. (2004). Hotspots Revisited. Cemex.
California Floristic Province, Wikipedia
Critical Ecosystem Partnership Fund

Feature image by Jeff P @ Picture Peak
Licensed under Creative Commons