California Conservation Summary

By Bruce A. Stein

With its mild climate, rich soils and abundant resources, California must have seemed very much like paradise to early explorers and settlers, leading to an uneasy alliance between myth and reality in the Golden State. Yet most would be pressed hard to conjure up a more fascinating cast of characters than those emanating from the evolutionary crucible of natural California.

Rare Species and Characteristic Habitats

The state leads the nation in its diversity of plants and animals but also has more endangered species than any other state except Hawaii. Nearly 5,000 plant species occur naturally in California, more than double the number in most states. Of even greater significance, almost a third of these are endemic – unique to California. West of the Sierra Nevada, nearly half the plant species are endemic, one of the highest such counts anywhere on the planet. Alongside the famed coast redwood, the world’s tallest trees, nearly half of the United States’ 50 or so conifer species are found in California – this in a country with more conifers than anywhere except China.

California’s animal roster is equally extraordinary, with more than 800 species of native vertebrates. Sixty-two of these are found nowhere else, a greater number of endemics than in any other state. California’s mammals rank first in the nation in both diversity and distinctiveness, while its birds rank fourth.

Of course, animals with backbones are just a fraction of all life, and California is also rich in insects and other invertebrates. Witness the fact that the mascot for the University of California at Santa Cruz celebrates one of the state’s most arresting spineless creatures, the banana slug. A denizen of the redwood forest, this yellowish gastropod can reach six inches in length. Butterflies are especially rich in the state, ranging from the rare El Segundo blue, whose largest population is found on remnant sand dunes adjoining Los Angeles International Airport, to the showy monarch, which overwinters in the thousands in the famous “butterfly trees” of Pacific Grove.

Geologically, much of California is not part of North America but consists of rocks that attached to the continent’s western edge as it slid over the edge of the Pacific plate. Periodic earthquakes serve as powerful reminders of the tectonic activity that helped form the state. This restless geology has produced an unparalleled variability in landforms, climates and soil types. In turn, physical complexity has fostered development of a welter of habitat types and has been the principal driver in the evolution of California’s unusual flora and fauna. The interaction of land and sea, with cold waters flowing down from Alaska, helped create a Mediterranean-type climate with mild, wet winters and hot, dry summers along much of the southern and central coast. The full diversity of landforms and climates, though, comprises more than 500 other distinct natural communities including various oak woodlands, grasslands, coniferous forests, desert communities and chaparral shrublands.

Among the most interesting of California’s many habitats are the seasonal wetlands known as vernal pools. An entire suite of wildflowers and annual grasses has evolved to take advantage of these ponds, which fill with winter rains and dry up slowly through the course of the spring. After sprouting under water, these plants flower and set seed on dry land. Concentric circles of colorful flowers follow the ever-shrinking edges of these pools, giving them the appearance of floral bathtub rings. Other highly specialized vernal pool inhabitants are fairy shrimp, many of which were not even known to science until the last decade. Some of these tiny crustaceans are extraordinarily rare, like the Riverside fairy shrimp, which is known from just five pools lying within a ten-mile radius.


California’s favorable combination of climate and soils not only favors plant and animal life but also creates delightful places for people to live. Accommodating a flood of humanity as the nation’s most-populous state has led to conversion of vast stretches of land to housing, agriculture and transportation and to large-scale exploitation of water, timber and mineral resources. As a result, many natural habitats have been severely depleted, and some are virtually gone. The most extreme example is the bunchgrass prairie that once covered the Central Valley. Of some 22 million acres of native grasslands thought to be present in the early 1800s, less than one percent now survives. Vernal pools have been largely plowed under or built over, and more than two-thirds have been lost.

Other serious problems have helped degrade ecosystems across the state. As crowding and costs in coastal regions have increased, population pressures have begun to spill over into the Central Valley. As a result, development threatens both agricultural land and the oak-covered foothills encircling the valley. Elsewhere, the spread of alien species like yellow star-thistle and disruption of natural fire and hydrologic cycles contribute to declines throughout the state.

California’s Future

Because so much of natural California has already been lost or altered, simply maintaining the status quo – even if possible – is not sufficient. It will also be necessary to restore the ecological functioning of key habitats and to nurse back to health severely depleted species like the reintroduced California condor or the small but slowly increasing population of southern sea otters. California’s myth and reality continue to conspire to create a land that is in many respects oversized – including the scale of its conservation challenge.


Bruce A. Stein is vice president for programs of the Association for Biodiversity Information and a former senior scientist with The Nature Conservancy. He was a coauthor and senior editor of the recently published book, Precious Heritage: The Status of Biodiversity in the United States.

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