Cosumnes River Preserve

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Cosumnes River Preserve
IUCN category V (protected landscape/seascape)
Location	Sacramento County, California
Nearest city	Sacramento, California
Coordinates	38°15′56″N 121°26′21″W / 38.26556°N 121.43917°W / 38.26556; -121.43917
Area	46,000 acres (190 km2)
Established	1987
Governing body	Joint management: The Nature Conservancy, Bureau of Land Management, Ducks Unlimited, Department of Fish and Wildlife, Department of Water Resources, Sacramento County Department of Parks and Recreation, and the state Wildlife Conservation Board.
U.S. National Natural Landmark
Designated	1976

The Cosumnes River Preserve is a nature preserve of over 51,000 acres (210 km²) located 20 miles (30 km) south of Sacramento, in the US state of California. The preserve protects a Central Valley remnant that once contained one of the largest expanses of oak tree savanna, riparian oak forest and wetland habitat in North America.^[1] Agricultural development has changed the landscape from groves of oaks and tule marshes to productive farmlands.^[2]

The Cosumnes River is the last remaining free-flowing river in California's Central Valley, with the preserve located on the river's lower reach where it joins the Sacramento-San Joaquin Delta tidelands. The area supports a diverse range of plant and animal life, including three species of oak as well as rare plants like the endemic northern California black walnut (Juglans hindsii).^[3] Notable features include the sandhill crane fall migration and the Tall Forest in Wood Duck Slough. More than 250 bird species, more than 40 fish species, and some 230 plant species have been identified here.

Located on the bird migration route, the Pacific Flyway, the preserve is designated an Important Bird Area by the American Bird Conservancy and National Audubon Society. Several rare birds, such as the Tri-colored Blackbird and the Greater Sandhill Crane, have been identified. Many bird species that have been extirpated from most of the Central Valley are returning to the area.^[4]

The preserve is between two growing urban centers, Sacramento in the north, and Stockton to the south, which threaten to constrict the protected areas to a narrow corridor extending from the Sierra foothills to the Sacramento River Delta.

In total, there are over 51,000 acres that are owned by the preserve partners with almost 40,000 acres of that being used for agricultural production. Of those 46,000 acres, approximately 12,500 acres are easement lands and 16,500 acres are fee-owned lands. Currently the Cosumnes River Preserve uses both public and private lands as a location for migratory birds throughout the year as well preserving natural riparian oak woodlands, vernal pools, wetlands, and grasslands.^[6] The Elderberry longhorn beetle, California giant garter snake, and the Swainson's hawk are three threatened or endangered species that have been found living on the preserve.