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Scientists met with each other and the public in February to share research on restoring salt ponds to natural tidal wetlands in South San Francisco Bay, California. The South Bay Science Symposium was held at the U.S. Geological Survey (USGS) campus in Menlo Park, California, on February 3, 2011. The USGS is a major player in a partnership of federal, state, and nonprofit organizations working to restore 15,100 acres of industrial salt ponds to a mix of natural tidal marsh, mudflat, and other wetland habitats by about 2058. This project, called the South Bay Salt Pond Restoration Project, is the largest tidal-wetland-restoration project on the U.S. west coast.

The February 3 meeting was the third in a series of science symposia held every couple of years to update the public on the project and the scientific research being conducted to guide it. Executive Project Manager John Bourgeois opened the meeting by describing some of the salt ponds that have already been breached and exposed to tides, noting, "I think we all love to see these levees come down and these breaches happen and new habitat being restored, but it can't happen without good science, and that's why we're here today."

Science is a critical component of the "adaptive management" being used to implement the project. The term refers to an iterative process of decision making in the face of uncertainty: decisions are made, their effects studied, and the findings used to guide subsequent decisions. Bourgeois said, "Other large-scale restoration projects across the country have talked about adaptive management, [but] we're actually doing it. We have an extensive science program targeted for specific questions that can inform future phases of restoration."

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San Francisco Bay has lost an estimated 85 percent of its historical wetlands to fill or alteration. This drastic decline in tidal-marsh habitats has decreased water quality, increased flood risks, and reduced populations of fish and wildlife that depend on tidal marshes. Restoration of the South Bay salt ponds—purchased in 2003 from Cargill, Inc. by state and federal agencies—will begin to reverse these trends and improve the overall health of San Francisco Bay. The goals of the project are to:

• restore and enhance a mix of wetland habitats,
• provide wildlife-oriented public access and recreation, and
• provide for flood management in the South Bay.

Bourgeois was followed at the podium by USGS scientist Laura Valoppi, Lead Scientist of the South Bay Salt Pond Restoration Project. Valoppi told the audience: "Part of the story that you'll hear today is that we're restoring areas; and, quite quickly, vegetation is coming in, fish are coming in and using these restored areas, birds are coming in and using them….So we are changing the ecosystem in the South Bay for the better, and it's an exciting time to be here." She outlined some of the key uncertainties being faced in this early phase of the project, which were the focus of many of the scientific talks that followed.

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USGS scientists Greg Shellenbarger (research hydrologist, Sacramento, California) and Bruce Jaffe (research oceanographer, Santa Cruz, California) discussed physical processes and South Bay sediment—the "ground floor for our marsh" according to Valoppi, who had observed that "if we don't have sediment coming in to fill these ponds, we won't have a marsh."

USGS scientists Jan Thompson (research biologist, Menlo Park, California) and Isa Woo (biologist, Vallejo, California) reported on their studies of benthic invertebrates, such as clams and worms, that live in the bay-floor sediment and how their communities vary with time of year and bay-floor elevation.

USGS wildlife biologists Arriana Brand (Vallejo) and Mark Herzog (Davis, California) described shorebird and duck responses to pond management (Brand) and the reproductive ecology of shorebirds (Herzog). Breeding populations of waterbirds currently make heavy use of salt-pond habitats in the South Bay. One goal of the South Bay Salt Pond Restoration Project is to restore a mix of habitats so that the needs of marsh species are balanced with those of populations that have come to rely on the salt ponds.

USGS scientists Mark Marvin-DiPasquale (microbiologist, Menlo Park) and John Takekawa (research wildlife biologist, Vallejo) discussed the effects of wetland restoration on mercury bioaccumulation (Marvin-DiPasquale) and the effects of sea-level rise on salt marshes and endemic wildlife (Takekawa)—two of several challenges to marsh restoration identified by Valoppi in her introductory remarks.

After the speakers had concluded, Valoppi acknowledged that "much of the data that we've collected so far really was our sort of 'before' picture, before a lot of the main breaches." She added: "We're understanding how complex the ecosystem is. It shows that we need to continue to study these areas, especially in these first early phases of restoration, so we can form subsequent phases with good scientific data."

Additional speakers from other agencies, organizations, and universities addressed the meeting, and numerous USGS and other participants displayed posters during the lunch break and at an evening reception. Learn more about the South Bay Salt Pond Restoration Project.