Spartina Species | Region 10 | US EPA

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Spartina Species

Spartina anglica in Island county (Livingston Bay) Courtesy of the Washington Department of Agriculture.

Spartina is an aggressive perennial clumping cordgrass that spreads rapidly in estuarine environments, forming large grassy meadows. Its dense root mats trap sediment, elevating the substrate, pushing out native species and creating new shoreline. In its natural environment, Spartina is considered beneficial, but on the west coast, it changes our mudflats, sand, and cobble beaches into grassy meadows. This threatens the shellfish industry, and displaces invertebrates which are important for migrating shorebirds, waterfowl, and juvenile salmon. Spartina is difficult to eradicate, partially because, compared to the aboveground biomass, five times more of the biomass is below ground.

New populations can also start from small fragments or seeds, and when small, it is sometimes difficult to distinguish from other grasses. Drift card studies on the WA and CA coasts, and in North Puget Sound and Canada, have been conducted to help understand where fragments and seeds are drifting, and predict possible new invasion sites.

Status in the Pacific Northwest: Oregon has only two introduced Spartina species; S. alterniflora and S. patens. In contrast, Washington has four introduced species. Of these, S. alterniflora and S. anglica have caused the most damage. S. alterniflora entered Willapa Bay on the Washington coast in the in the 1890s, as discarded packing material associated with east coast oysters. Later it was also purposefully introduced into Puget Sound for dike stabilization. S. anglica was also introduced into Puget Sound, and it quickly became the dominant Spartina species there. S. densiflora, a South American species, and S. patens, were discovered in Grays Harbor and Jefferson County, respectively. The introduction pathways for S. patens and S. densiflora are unknown. Eleven counties in Washington now have infestations of one or more species.

In 1995, the gravity of the Spartina threat was finally recognized, and the Legislature passed laws mandating control, and identifying the Washington Department of Agriculture as the lead agency. The Department established a state coordinator position, and began an eradication effort, ultimately involving a wide coalition of interested groups, and using a variety of chemical, physical and biological control methods. But the infestation continued to spread, and in 2002, the overall statewide infestation peaked at over 9000 acres. Hope of control was dimming, until concerted effort, a significant infusion of funding, and later, use of a new chemical, Imazapyr, finally began to cause significant reductions. By the end of 2006, the infested area was dramatically reduced to approximately 2200 acres, and there is now reason to hope it may actually be eradicated or at least reduced to small easily treated patches.

What can you do? Learn to recognize Spartina. For more information, or to report new infestations, contact:
In Washington: 1-360-902-1923 (State Spartina Coordinator)
In Oregon: 1-866 INVADER (hotline)
In Alaska: 1-877-INVASIVE (hotline)

The links provided may be outside the domain.

Field Guide to Puget Sound Spartina

Spartina Eradication Program - 2006 report

Oregon Spartina Response Plan

Spartina alterniflora Fact Sheet

Spartina densiflora Fact Sheet

Spartina anglica Fact Sheet

Spartina patens Fact Sheet

WA Spartina control program annual reports

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