ARS | Publication request: Flora and ecological profile of native and exotic estuarine wetland vegetation by hydrogeomorphic setting at Rush Ranch, Suisun Marsh

Submitted to: Government Publication/Report
Publication Type: Government Publication
Publication Acceptance Date: November 1, 2011
Publication Date: December 14, 2011
Citation: Grewell, B.J., Whitcraft, C., Baye, P. 2011. Flora and ecological profile of native and exotic estuarine wetland vegetation by hydrogeomorphic setting at Rush Ranch, Suisun Marsh. Pg. 79-144 in: Ferner, M.C. editor, 2011. A profile of the San Francisco Bay National Estuarine Research Reserve. San Francisco Bay National Estuarine Research Reserve. San Francisco, California. 345 p. plus appendix.

Interpretive Summary: The National Estuarine Research Reserve System NERR) is a network of 28 reserves established for long-term research, education and stewardship of the nation's estuaries. The San Francisco Bay NERR was established in 2003, and managed as a partnership between NOAA, San Francisco State University, California State Parks, and Solano Land Trust. The goal of this partnership between NOAA and local coastal entities is to study and protect vital coastal and estuarine resources. This manuscript is an invited contribution to a Site Profile document that NOAA requires of all reserve sites. NOAA and San Francisco State University will self publish the SFB NERR profile as a government report that will be printed, and also widely available to interested public as a free internet download from NOAA’s website (www.nerrs.noaa.gov). This research provides a baseline profile and analysis of estuarine vegetation at a National Estuarine Research Reserve (NERR) site (Rush Ranch) in the Suisun Marsh reach of the San Francisco Bay Estuary. The data analyses presented quantify vegetation by hydrogeomorphic setting, and provide a historic perspective of vegetation change. The results suggest 27% of the current plant species in the wetlands are of exotic origin, and several are highly invasive. These data will contribute to NOAA and NERR objectives for stewardship and restoration of critical federal estuarine reserve sites. This contribution also includes a detailed flora compiled from more than twenty years of field surveys. The manuscript and flora (appendix) provide an ecological framework for future monitoring, research and adaptive conservation management at Rush Ranch and in the greater San Francisco Estuary.

Technical Abstract: The manuscript includes a profile of the ecology and distribution of estuarine wetland vegetation at the Rush Ranch reserve site in the brackish Suisun Marsh reach of San Francisco Estuary The data and analyses will serve as a baseline for future scientific research and conservation management. A detailed analysis of the distribution and abundance of both desirable native plant communities and exotic, invasive weeds is provided that will aid weed management planning and restoration efforts. Rush Ranch includes 4 major estuarine geomorphic units that are widely distributed in the region and support vegetation: subtidal channel beds, fringing tidal marsh, tidal marsh plain and tidal marsh-terrestrial ecotone. These are distinguished by small variations in hydrology and elevation. We evaluate vegetation within each of these landforms, considering each vegetation community as a function of changing physical environment and biological iterations. Past land-use and exotic plant species invasions have substantially altered Rush Ranch tidal marsh vegetation patterns. Our results indicate 27% of the flora to be exotic species, and several are highly invasive. Despite these threats, the reserve’s position in the landscape provides important and increasingly rare habitat linkages between the tidal marsh and upland grasslands, providing great potential for restoration and migration corridors for vegetation response to sea level rise and other climate change factors. We present a detailed flora and vegetation analysis by hydrogeomorphic setting to provide an ecological framework for future monitoring, research and adaptive conservation management.