Recent (1975–2004) Vegetation Change in the San Francisco Estuary, California, Tidal Marshes

Abstract

Abstract WATSON, E.B. and BYRNE, R., 2012. Recent (1975–2004) vegetation change in the San Francisco Estuary, California, tidal marshes. The establishment and monitoring of vegetation plots provide unique information on the spatiotemporal dynamics of plant distributions. In 1975, U.S. Geological Survey (USGS) scientists Atwater and Hedel established vegetation transects at six tidal marshes spanning the salinity gradient of the San Francisco Estuary, California, to establish a baseline against which future vegetation changes could be measured. Since 1975, estuarine salinity has increased because of water diversion, whereas sea level has risen at rates that exceed late-Holocene background levels. During the summers of 2003–04, we reoccupied these transects and measured plant composition to better understand the response of marsh vegetation to these hydrologic changes. Our results indicate that during the past 30 years, Sarcocornia pacifica, the most salt-tolerant plant species, increased in cover, whereas ...