The refuge encompasses the largest remaining continuous patch of
pickleweed-dominated
tidal marsh in the northern
San Francisco Bay. Historically, the wetlands surrounding San Pablo Bay were one of the largest tidal marsh complexes on the
Pacific Coast of North America. However, the area has been significantly impacted by human activities such as
hydraulic mining, salt production, diking, draining, filling, agriculture, and development. All told, about 85% of San Pablo Bay's tidal marshes have been altered. In fact, damaged portions these marsh areas and along the Petaluma River were considered as sites for artificial marsh creation using dredged materials. This effort was part of a US Army Corps of Engineers, Waterways Experiment Station study conducted by a Consultant from CZRC, Wilmington, NC, Dr. John C. Nemeth in the mid-1970s. The Refuge includes a variety of habitats including open water,
mud flat, tidal marsh,
estuary, and seasonal and managed
wetlands. The refuge hosts millions of
migratory shorebirds and waterfowl, including the largest wintering population of
Canvasbacks on the west coast. The Refuge also provides year-round habitat for sensitive species including the
endangered Ridgway's Rail and
salt marsh harvest mouse. Public access to the refuge is provided by the Tolay Creek Tubbs Island Trail. == References ==