Park District Works to Control Invasive Spartina

Tuesday, July 8, 2008

The East Bay Regional Park District, in conjunction with the Invasive Spartina Program (ISP) of the California Coastal Conservancy, is undertaking a program to manage non-native Spartina (cordgrass) in the San Francisco Bay estuary. Spartina alterniflora is an invasive plant species threatening the mudflats of San Francisco Bay. The open mudflats are essential to the ecology of the Bay and an integral part of the feeding habitat for thousands of migratory shorebirds that utilize the Pacific flyway.

Efforts to control the spread of non-native Spartina are currently entering the fifth year. Park crews and contractors will treat Spartina at Hayward Regional Shoreline, Martin Luther King Shoreline, Oyster Bay, Point Pinole Regional Shoreline, and Eastshore State Park from July through October 2008. District crews and consultants will spray a State and EPA approved herbicide (growth inhibitor) on the Spartina plants. 

The herbicide is mixed with a surfactant and blue dye to improve the efficacy of the herbicide and help track areas treated. These herbicides and their adjuvants have no adverse impacts to human health or safety. The mixtures likewise have been tested and are nontoxic to mammals, birds, fish, and aquatic invertebrates. Once sprayed into the near shore area colonized by Spartina, the herbicide that is not absorbed by the plant is quickly broken down by sunlight and diluted by the tides.

A helicopter will be used for aerial applications on July 22. During other treatment operations through October, ground crews will spray from backpacks, trucks, or boats.  As per District herbicide use regulations, adjacent trails will be closed to the public for approximately 12 hours during and after treatment.

Following treatment, the Spartina plants will begin to brown as a result of treatment and normal fall dieback.  The real determination of the effectiveness of the treatment will be observed next spring when the plants would normally begin to grow.  Although stands of dead plant material may persist for several years, the spread of non-native Spartina is expected to be halted and native marsh plants will begin to colonize the area. Similar treatments in 2006 resulted in a 40 percent reduction in this invasive plant. As a result of continued efforts, the Bay Area populations of non-native Spartina have shown dramatic declines in shoreline coverage.

For more information on the Regional Spartina control program contact Pete Alexander of the East Bay Regional Park District at (510) 544-2342, or Peggy Olofson of the ISP at (510) 548-2461. For more information of the Spartina Control efforts, visit www.spartina.org.

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