Invasive Spartina Eradication
Pacific cordgrass (Spartina foliosa) is a major component of tidal marsh vegetation in San Francisco Bay, which historically covered thousands of acres across the region. In the 1970s, the Army Corps of Engineers introduced Atlantic cordgrass (Spartina alterniflora) to the Bay, which hybridized with its native cousin. The hybrids expanded aggressively across lower tidal mudflats and tidal marshes, displacing Pacific cordgrass, altering vegetation communities and “engineering” the ecosystem through sediment accretion. Tidal marshes are important habitat for the federally-listed Ridgway’s rail, salt marsh harvest mouse, and migratory waterfowl. It became apparent that cordgrass across the entire bay would be replaced by hybrid cordgrass and mudflat habitat would be lost if the situation was not addressed.
In the year 2000, the state-led Coastal Conservancy and Federal-led US Fish and Wildlife Service initiated the Invasive Spartina Project (ISP) to head up a multi-agency response effort with the goal of eradicating invasive Spartina from the Bay. After four years of planning and environmental documentation, treatment started in 2005. To date, the overall population of invasive Spartina in the bay has been reduced 95%, from 805 acres to less than 38 acres across a 70,000-acre project area (see the 2021-2022 Monitoring and Treatment Report, the latest treatment schedule, and the 2023 water quality report). More than 450,000 native plants have also been planted, restoring many acres of Ridgway’s rail habitat (see the 2023 Ridgway’s rail survey.
From 2007 to 2012, the ISP released a series of floating wooden drift cards to increase our understanding of dispersal patterns within the Estuary, and potentially help predict where to survey for potential new infestations. Before the 2023 field season kicked into high gear, the ISP completed a report on our Drift Card Study.
Since 2019, Cal-IPC has partnered with the ISP to continue to lead this highly successful effort toward completion. The regional collaboration comprises more than 150 partner groups, including private, local, state, and federal landowners, resource agencies, and community stakeholders in all 9 counties. This extensive partnership and the innovative project structure and tracking methodology that have evolved through this program presents a model for landscape-scale invasive species response.
ISP received a Cal-IPC Outstanding Project Award in 2012 and an Outstanding Implementation Project Award from the San Francisco Estuary Project in 2015. It has also been featured in several publications, including Bay Nature Magazine, Alameda Magazine, ESRI ArcNews, and the San Jose Mercury News.
Our outreach program includes community presentations. Some recorded sessions are available to watch. Upcoming presentation dates will also be posted here.
- June 11, 2021 – Webinar as part of the California Invasive Species Action Week. View a recording of the talk by Restoration Program Manager Jeanne Hammond and Biologist Lindsay Faye Domecus.
- July 14, 2021 – Presentation for CNPS – Santa Clara Valley Chapter. View a recording of the talk by Restoration Program Manager Jeanne Hammond and Biologist Lindsay Faye Domecus.
- Nov. 17, 2021 – Presentation for CNPS – East Bay Chapter by Restoration Program Manager Jeanne Hammond and Biologist Lindsay Faye Domecus.
- Dec. 9, 2021 – Presentation for CNPS – Yerba Buena Chapter. View a recording of the talk by Monitoring Program Manager Tobias Rohmer and Biologist Lindsay Faye Domecus.
- Dec. 10, 2021 – Presentation for Sierra Club, San Francisco Chapter. View a recording of the talk by Biologists Jen McBroom and Lindsay Faye Domecus.
- Dec. 16, 2021 – Presentation for San Francisco Integrated Pest Management Technical Advisory Committee. View a recording of the talk by ISP Treatment Program Manager Drew Kerr.
- May 3, 2022 – Site visit and presentation for a Merritt College class on Invasive Plants, led by Monitoring Program Manager Tobias Rohmer and Biologist Lindsay Faye Domecus.
- May 12, 2022 – Presentation for the South Bay Salt Pond Restoration Science Symposium, with a brief overview of two other invasive plants of concern to marshland habitat to increase awareness of these lesser-known invaders. View a recording of the talk by ISP Treatment Program Manager Drew Kerr.
- October 20, 2022 – Two presentations at the CNPS Conference in San Jose. View a recording of the presentation by Debra Ayres (CNPS El Dorado Chapter, University of California, Davis, retired). She gives historical context on the hybrid Spartina invasion of San Francisco Bay. Also view a recording of the presentation by Restoration Program Manager Jeanne Hammond and Biologist/Geneticist Brian Ort.
- November 14, 2022 – Presentation for CNPS – Marin Chapter. View a recording of the presentation by ISP Treatment Program Manager Drew Kerr and biologist Simon Gunner.
- May 18, 2023 – Presentation to the Golden Gate Audubon Society. View a recording of the talk by Monitoring Program Manager Tobias Rohmer and Environmental Biologist Lindsay Faye Domecus (available on the website for a limited time).
- September 19, 2023 – Presentation for the San Francisco Estuary Partnership Wetland Migration Workshop. View a recording of the talk by Restoration Program Manager Jeanne Hammond (her talk starts at 42:09).
- October 27, 2023 – Presentation at the 2023 Cal-IPC Symposium. View PowerPoint by Program Treatment Manager Drew Kerr.
- November 30, 2023 – Presentation to the Delta Invasive Species Symposium in Sacramento. View a recording of the talk by Program Treatment Manager Drew Kerr (his talk starts at 54:36).
- December 14, 2023 – Presentation to the Marin Audubon Society, by Biologists Jen McBroom and Lindsay Faye Domecus (no recording available).
- (upcoming) February 6, 2024 – Presentation to the Ohlone Audubon Society, by Monitoring Program Manager Tobias Rohmer.
Outreach emails share seasonal progress. Join the ISP Email List to receive updates.
Plants being managed
LocationSan Francisco Bay Estuary Project map in Calflora
Tidal marsh habitat supporting endangered wildlife (Ridgway’s rail, salt marsh harvest mouse) and other marsh-dependent species, and tidal mudflats supporting migratory waterfowl and shorebirds.
Eradication of hybrid Spartina from the San Francisco Bay. This is a long-term goal and is considered feasible due to the isolated nature of this hybrid swarm, the lack of new introductions, and the success of the program to date.