Sacramento National Wildlife Refuge, USA Photograph by Todd Keeler-Wolf/California Dept. of Fish and Game   Western North America: Western United States Temperate Grasslands, Savannas, and Shrublands   21,300 square miles (55,100 square kilometers) -- the size of New Hampshire and Vermont combined Critical/Endangered

· Valley Mosaic
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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Valley Mosaic

Imagine a valley with desert areas, prairies, savannas, woodlands, marshes, and an immense river delta. That's what the California Central Valley once was like. This region once supported incredibly diverse plant and animal species, but now most of the Central Valley's original habitats have been destroyed or altered.

Special Features

Have you ever heard of a vernal pool? This is a body of water that fills with rainwater during part of the year and then completely dries out during the rest of the year. Because a vernal pool completely dries up, fish cannot survive in it. That makes it ideal habitat for species whose eggs and young would be too vulnerable to predation by fish. Species such as fairy shrimp and tadpole shrimp are two of the species that depend upon vernal pools in this ecoregion. During the wet springtime, the types of flowers around the pools change as the water in the pool evaporates and recedes. Some of these flowers include California poppies, lupines, and purple owl clover. After the winter rains, these flowers put on quite a spring show by blooming all at the same time.

	More than 526 exotic species of plants have been introduced in the state of California, many of which occur in the grasslands of the Central Valley and threaten native species. In most Central Valley habitats, native species comprise less than one percent of the plants present today.

Wild Side

The grasslands of the California Central Valley once provided plentiful food for plant eaters such as pronghorn, elk, mule deer, California ground squirrels, and kangaroo rats. Their predators included coyotes, mountain lions, ringtails, bobcats, and San Joaquin Valley kit foxes, which are now a federally endangered species found only in the southern California Valley foothills. River areas were lined by a wide swath of trees such as willows, western sycamores, box elders, Fremont cottonwoods, and valley oaks. These riparian forests provided stopover points and breeding areas for huge flocks of birds migrating all the way from the tropics. They were also home to the valley elderberry longhorn beetle, now a federally endangered species. Some vernal pools are also the home of the rare Delta green ground beetle. The marshes of the valley's delta area provided food and shelter for thousands of waterfowl during the winter.

Cause for Concern

The California Central Valley was once one of the most diverse, productive grasslands in North America. But times have changed, and virtually all Central Valley habitats have been altered. Several factors have caused this change: introduced species, clearing for agriculture, growth of cities, fires, pollution, logging, channeling of rivers, building of dams, and conversion of habitat to pasture for livestock grazing. The result? As many as 66 percent of the vernal pools have been destroyed and less than 6 percent of the original marsh area remains. The other habitats exist as only small, scattered fragments. These isolated areas no longer have the habitat connections that animals such as reptiles and amphibians depend on for movement to find food and mates.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.