The effects of Atlantic cordgrass on the sensitive marine estuaries of the West Coast will be studied under a $3.8 million grant awarded to UC Davis researchers by the National Science Foundation. The project, which includes colleagues at the Scripps Oceanographic Institute, UC San Diego and the San Francisco Estuarine Institute, will provide one of the first rigorous studies of the value of ecosystems, including human, economic and environmental benefits, says principal investigator Alan Hastings of the Department of Environmental Science and Policy. Native to the East Coast of the United States, Atlantic cordgrass (Spartina alterniflora) is a big problem in estuaries on the West Coast, says Hastings. The invading plant changes the ecology of estuaries, with far-reaching effects on native plants and animals, and an impact on people who live, work and play along the coast. "Our estuaries lack large land plants which grow in salt water," said ecologist Don Strong, "so they have evolved as mudflats." The cordgrass has no competitors or enemies in this environment, so it spreads rapidly. The plants slow down water flow and increase sedimentation, changing mudflats into intertidal meadows as the high-water line moves to the middle of the estuary. "This plant violates the law in the Pacific states," joked Strong, pointing out that land reclamation is illegal in California. "This is among the most profound changes you can impose on these estuaries." Most of the West Coast is rocky shore, Strong said, and humans have damaged most of the few natural estuaries. What remains is home for a unique collection of migratory birds, he said, but these habitats are threatened by cordgrass invasion. Cordgrass also threatens harbor seals, which need tidal mud islands as nurseries for their pups, Strong said. Cordgrass encroachment decreases the value of river estuaries to humans -- both in financial terms, and in non-commercial and esthetic values. The research will look at all these different impacts of cordgrass on the ecosystem. "It's an example of trying to understand an invasion," Hastings said. "Complex enough to see the effects of a species on the environment, simple enough for us to understand completely." The team will create a dynamic model of cordgrass invasion, using extensive historical records and data collected by aerial and satellite photography. Resource science specialist Susan Ustin will lead the remote-sensing part of the project. They will then compare the results of the model with detailed observations of West Coast estuaries, including San Francisco Bay and Willapa Bay, Washington. The remote-sensing approach builds on research by Janie Civille, a graduate student at the Bodega Marine Laboratory, UC Davis. Civille has used aerial infra-red photography to look at the spread of cordgrass in Willapa Bay. The photographs show that cordgrass is spreading faster in some parts of the bay than others, and that the rate of spread changes from year to year. The El Nino events of the 1990s were associated with a rapid spread of cordgrass, Civille said. Civille's research also has yielded a finding with important implications for cordgrass control, according to Strong. It shows that the plant spreads by seeding new areas, rather than by vegetative spread. Control efforts should therefore be directed at the older, mature plants, rather than at younger plants at the expansion front, Strong said. The project integrates a variety of approaches, Hastings said. In addition to computer models and remote sensing, there will be measurements of water flow, sediment accumulation, and surveys of mammals, insects and birds. The impact of cordgrass on food webs will be studied by Ted Grosholz from UC Davis, and Lisa Levin from the Scripps Institute. These observations will be used to refine the model, which will then be used to predict the effects of cordgrass invasion on bird populations in estuaries. An important aspect will be to look at the effect of cordgrass invasion on the value of the affected area to humans. Estuaries have a dollar value from activities such as navigation, fishing and sailing, but also have non-commercial and esthetic values that are affected by cordgrass invasion. Analysis of the economic effects of cordgrass invasion will be led by David Layton of the Department of Environmental Science and Policy. Community outreach activities will play a major role in the project. "The aim is to educate the public on invasive species, like Spartina," said Grosholz, who will coordinate the outreach activities. A series of workshops will begin in the first year of the project, Grosholz said. Grosholz hopes that as well as education, the outreach program will help to prevent the unintentional spread of invasive cordgrass. The UC Davis grant is one of the largest awarded as part of $52.5 million awarded by NSF for biocomplexity research. Studies of biocomplexity aim at the "big picture," combining ecology and biology with disciplines as diverse as physics, geology, engineering and economics.