Swinomish
Office of Planning &
Community Development
LACONNER, WA, USA

What is Spartina?

Spartina is a non-native species of cordgrass that grows on nearshore coastal tidelands, mudflats, and other areas of saltwater influence.

These near-shore coastal tidelands are significantly threatened by the presence and spread of the invasive weed, Spartina.

Acres of Spartina has turned the backwaters of Turners Bay into a Spartina mono-culture. Spartina is the blue-green grass in the background.

Controlling Spartina

The Swinomish Reservation includes 7,300 upland acres and 2,900 acres of Tribally owned tidelands. Thirty-five miles of marine waterfront form 95% of the exterior boundary of the Reservation. Tidelands and marine areas make up most of the Reservation surface waters, all suseptible to Spartina's invasion.

Successful containment and eradication of Spartina are dependent on completing consecutive and successful years of physical control measures. The Tribe, since identifying the presence of Spartina on the Reservation in the winter of 1995, has successfully funded on-Reservation survey and control efforts, and collaborated with community groups, environmental groups, and local, state and federal agencies in public education, training, and control throughout the Tribe's tidelands and in neighboring Puget Sound locations.

The Swinomish Tribal Community has removed over 7,000 cubic yards of Spartina since 1997, along with repetitive mowing of the Spartina remaining in the nearly 200 affected acres of tidal flats. The Tribe remains committed to eliminating the threat of Spartina through its Spartina program. The Management Control Plan adopted by the Tribe targets control through:

1) limiting seed sources through mowing, cutting, and collection,

2) reducing the vitality of clones through successive and frequent mowing, and

3) actual removal by pulling and digging.

A spartina seedling after a few months growth. Spartina seeds float on the water and are spread by the tides. Spreading of seeds can be limited by mowing the Spartina before the seeds set. Although, the mowing with weedeaters is labor intensive in the infested mudflats.

Why is Spartina a problem?

Spartina is transforming native mudflats and salt marshes into monotypic Spartina upland meadows in coastal Washington State. As an aggressive colonizer, Spartina displaces native plants and animals historically associated with Puget Sound, such as eelgrass and macroalgae.

A study of out-migrating juvenile chum salmon determined that eelgrass and its associated algae are the basis of the food web for this species in the estuary (Simenstad and Wissmar, 1985).

In addition, Spartina meadows facilitate increased sedimentation and can dramatically incease tide flat elevation. The Washington State Conservation Commission recently identified Spartina as a threat to salmonid survival in the Stillaguamish and Island County WRIAs (Water Resource Inventory Areas).

Shellfish species that depend on historical abiotic factors cannot survive with increased sedimentation and tide flat elevation. A primary factor contributing to species endangerment is habitat destruction and a secondary factor is introduction of non-native species.

Spartina has the potential to invade mudflats and salt marsh areas throughout Puget Sound if allowed to grow uncontrolled. To date, Spartina has impacted over 8,000 acres in Puget Sound (Washington State Dept. of Agriculture, 1999).

How can you help?

Volunteer!

The Swinomish Noxious Weed Control Program hosts Skagit Dig Days and other volunteer Spartina removal activities during the summer. Please call our office for dates and times.