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The Cosumnes River Preserve is a nature preserve of 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.〔( Cosumnes River Preserve history. )〕 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'').〔(Calflora taxon report )〕 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. The National Park Service has been protecting the area since 1976 when the agency added the Cosumnes River environment to the National Natural Landmark Program as the Cosumnes River Riparian Woodlands. This program conserves examples of the country's natural history and is the only natural areas program of national scope that identifies and recognizes the best representations of biological and geological features in both public and private ownership. ==History== The fast-disappearing valley oak (''Quercus lobata'') tree of California's Central Valley prompted The Nature Conservancy, a nonprofit conservation organization, to find and protect these trees from the rapid urban growth in the 1980s. After surveying the entire valley, the best stands were found on the lower Cosumnes River and a preserve of was established in 1987. With further study, scientists better understood the river-oak forest relationship; the "swamp oak" is another name for the valley oak because it thrives on deep, alluvial soils (which also makes good farmland) that the river deposits with seasonal flooding. The Conservancy realized that it needed a larger, broader view that included the river, floodplains, the whole watershed. As a result, in 1993, the conservancy moved beyond its hallmark of outright land purchases and into cooperative agreements with farmers, water-and flood control agencies, and shared in management responsibility with federal, state and local land agencies toward the goal of protecting a watershed of in size. Some partners in the cooperative agreement include: US Bureau of Land Management, California Department of Water Resources, California State Lands Commission, Sacramento County Department of Regional Parks, California Department of Fish and Wildlife, Wildlife Conservation Board, Ducks Unlimited, Inc. and private landowners. In 1998, the Howard Ranch, located within the watershed area, was put up for sale. The ranch contains important wetlands, including vernal pools, and the conservancy purchased the property of property using a combination of grants and loans. The loans included funds from the federal Clean Water Act's State Revolving Fund. This was the first time these funds had been used to purchase and protect wetlands. Currently, the preserve is more than with educational and scientific studies being conducted in one of the largest conservation efforts begun on a watershed-sized scale. Collectively known as the Cosumnes River Project, it is a broad-based work to restore and protect the integrity of the river and associated landscapes including Central Valley habitats and wildlife. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cosumnes River Preserve」の詳細全文を読む スポンサード リンク
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