Two new US Ramsar Sites in the state of California

01/02/2005

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The United States designates two Wetlands of International Importance in California

To commemorate World Wetlands Day 2005, two sites designated by the United States of America have been added to the List of Wetlands of International Importance, the Tijuana River National Estuarine Research Reserve (TRNERR) and Grassland Ecological Area, both in the state of California. TRNERR is one of the few unfragmented estuaries in southern part of the state and is located at the very southwestern corner of the country on the border with Mexico. Grassland is the largest remaining freshwater wetland complex in the state and is renowned for its very large congregations of wintering waterfowl and shorebirds. Brief site descriptions have been prepared by Ramsar's Iván Darío Valencia based on the information supplied in the Ramsar Information Sheets accompanying the designations.

Grassland Ecological Area (65,000 ha; 37º10'N 120º50'W) is a National Wildlife Refuge and Western Hemisphere Shorebird Reserve located in the Central Valley in the San Joaquin River Basin. The largest remaining contiguous block of freshwater wetlands in California, it consists of semipermanent and permanent marshes, riparian corridors, vernal pool complexes, wet meadows, native uplands and grasslands, featuring Alkali Sacaton grassland Sporobolus airoides and the endemic Delta button celery, Eryngium racemosum. The site is renowned for its wintering waterbirds which reach several hundred thousands every winter. These include Sandhill Cranes (Grus canadensis), 19 duck species (Northern pintail Anas acuta; Green-winged teal Anas crecca; Northern shoveler Anas clypeata; Canvasbacks Aythya valisineria and others), 6 species of geese, tens of thousands of shorebirds (most abundantly Western Sandpiper Calidris mauri, Dunlin Calidris alpina and Long-billed dowitcher Limnodromus scolopaceus). The site is home to four endangered shrimps as well the threatened Giant garter snake Thamnophis gigas. Due to flood-control and irrigation projects the entire hydrology of the valley had been dramatically altered, but water quality and allocation issues have been successfully addressed with the Central Valley Project Improvement Act in 1992. Most of the wetlands are managed by the controlled application of water using a series of canals and control structures, mimicking historical flood patterns with pulses of high water flow during winter and spring. The largest potential threat to the site is urban development. Ramsar site no. 1451.

The Tijuana River National Estuarine Research Reserve (TRNERR) (1,021 ha, 32º33'N 117º07'W), a National Wildlife Refuge, lies on the border with Mexico facing the city of Tijuana -- it is one of the few unfragmented estuaries and coastal lagoons in Southern California. It is a seasonally marine-dominated estuary experiencing freshwater input only during the wet winter period, though its mouth remains open throughout the year. It has several sensitive habitats such as sand dunes and beaches, vernal pools, tidal channels, mudflats and coastal sage scrub. The site is critical habitat for nationally endangered species and subspecies such as the San Diego Fairy Shrimp Branchinecta sandiegonensis, the Light-footed Clapper Rail Rallus longirostris levipes and the Salt Marsh Bird's Beak Cordylanthus maritimus maritimus; as well as nursery grounds for commercially important fish like the Diamond turbot (Hypsopsetta guttulata) and the California halibut (Paralichthys californicus). Dirt roads and border patrol off-road vehicles are a primary cause of concern because of the impacts of lighting, noise and sedimentation, already serious due to strong erosion and runoff from the shared basin with Mexico. The site is unfortunately isolated from surrounding habitat by urban areas and there are problems with introduced species. A multi-phased restoration program designed to restore tidal exchange and wetland habitats is in place, as well as a management plan. The site is administered jointly by California State Department of Parks and Recreation (DPR) and the United States Fish and Wildlife Service (USFWS). Ramsar site no. 1452.

The United States now has 21 Wetlands of International Importance, with a surface area totaling 1,258,751 hectares.

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