Suisun Marsh
Map SatelliteSuisun Marsh is the largest remaining wetland in the State. Though there is some salt marsh, particularly in the southern portions, today approximately 90% is brackish or freshwater marsh.
In its natural state most of the area was a brackish marsh, but much of it has been modified by levees to provide a habitat for waterfowl. The waterfowl areas (see Grizzly Island Wildlife Area and Joice Island) that are not cultivated are managed primarily as freshwater marshes.
Tules, Scirpus spp., and cattail, Typha latifolia, are the dominant species of the natural vegetation in the marsh. Five rare plants have been recorded from the marsh and the adjacent uplands, Cicuta maculata var. bolanderi, Cirsium hydrophilum var. hydrophilum, Cordylanthus mollis ssp. mollis, Lasthenia conjugens and Lilaeopsis masonii.
The marsh, uplands and adjacent waters are of major import on the Pacific Flyway, being a feeding, resting or wintering area for tens of thousands of migratory shorebirds and waterfowl. Over 200 species of birds have been observed in the area. Among the more common migratory species are the white-fronted goose, Anser albifrons (the rare subspecies Anser albifrons gambelli occurs here, too), mallard, Anas platyrhynchos, pintail, Anas acuta, green-winged teal, Anas carolinensis, widgeon, Mareca americana, and canvasback, Aythya valisineria. There are heron and egret rookeries in the area. The uncommon black rail, Laterallus jamaicensis, occurs here.
Forty-plus mammals have been observed in the area, including the endangered salt-marsh harvest mouse, Reithrodontomys raviventris, and the endemic Suisun shrew, Sorex sinuosus.
The marsh sloughs form a major habitat for the striped bass, Roccus saxatilis, which is one of 24 species of fish inhabiting the marsh and adjacent waters.
Integrity: Most of the area is managed for waterfowl habitat, and the upland grasslands are grazed. There are levees, roads, various buildings, overhead wires, underground pipes and some natural gas wells.
Use: Research, educational, observational, present, on the public portions. About 75% of the area is privately owned, primarily by duck clubs.
Ref: Gill, R. and A. R. Buckman, 1974. The Natural Resources of Suisun Marsh; Their Status and Future. Calif. Dept. of Fish and Game, Coast. Wet. #9, 152 pp.
November 1977
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman
