The Cosumnes River Preserve is a nature preserve of over 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. Agricultural development has changed the landscape from groves of oaks and tule marshes to productive farmlands.
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 californica var. hindsii). 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.
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.
History
The Miwok Native American tribe settled the area around the Cosumnes River Preserve many centuries ago. They survived up through the 1900s with a 1910 census counting 670 Miwok Native Americans left. According to a 1770 estimate, there were approximately 9000 Miwok present.[7] Population density for the Miwok tribe was about 10 persons per square mile which may have been the most out of any California tribe.[8] The entire Miwok tribe consisted of 28 small groups which could range from 300 to 475 people. The Miwok people ate a diet consisting of acorns, various types of other seeds, deer, and fish. The local Miwok people practiced burning and other management practices to shape the land to create more opportunity for food. Through these methods of enhancing floodplains in the area, fish species may have had lower mortality rates and increased growth.[9] After the mid 1700s, the Miwok way of life started to change with the arrival of the Spanish.
Around 1770, a small group consisting of Spanish explorers decided that the Cosumnes River Preserve and other places within the Central Valley was a perfect pasture for grazing animals. Trappers came into the area around the preserve in the early 1800s but found that there was no place to settle and the fur trapping was not worth it. The Mexican government started issuing land grants in 1844 and John Sutter who was a European immigrant was one of the first to colonize the Cosumnes River area. John Sutter founded the colony New Helvetia and soon some of his assistants moved out to the Cosumnes River Preserve area. Once the California gold rush started in 1848, many miners settled in along the Cosumnes River hoping to find gold and get rich. Once realizing that there wasn't very much gold in the region, they dammed the river and changed the landscape to grow hay, wheat, and various types of fruit. The Miwok people lost sources of food that they relied on and soon after villages and burial grounds were destroyed. Shortly after, the Miwok moved out of the region where the Cosumnes River Preserve is and in 1999, the last person to speak Plains Miwuk died.