Invasive Species—Spartina Eradication Project in Willapa Bay
Spartina alterniflora was the first spartina species introduced into Washington waters in the late 1800s when, we suspect, it was used as packing material in a shipment of east-coast oyster spat. The idea is that a shipment was dumped into Willapa Bay, where the spartina plants took root and slowly spread vegetatively for about 50 years. In the mid-1950s, S. alterniflora was established enough to set seed and thus began its more rapid increase. It was later introduced into Puget Sound for shoreline stabilization purposes and to provide cover for waterfowl hunters. S. anglica was introduced in Port Susan Bay in 1961 for erosion control and cattle forage. It has since spread to other parts of north Puget Sound. A small population of S. patens exists at the mouth of the Dosewalips River; its date of introduction is unknown. The most recent spartina discovery occurred in the fall of 2001 during routine surveys for spartina in Grays Harbor and northern Puget Sound. Two populations of Spartina densiflora were found. These findings were the first for S. densiflora in Washington State and represent the species' northernmost distribution.
The infestation is most advanced in Willapa Bay. In 1984, the extent of Spartina alterniflora in Willapa Bay was estimated at 300 acres. In 2003, the estimate was 8,500 acres of solid spartina spread out over more than 35 percent (15,000 acres) of the Bay's intertidal region. RCW 17.26 (“Control of Spartina and Purple Loosestrife”) was enacted by the Legislature in 1995, which directed funding to three agencies, DNR, Washington Department of Fish and Wildlife (WDFW), and Washington State Department of Agriculture (WSDA) as the state lead, to begin a control program. Control of spartina in Willapa Bay and Puget Sound has been ongoing since then.
We've come a long way from our humble beginnings using brush cutters and backpack sprayers to treat 100 acres in a season. In recent years, an unprecendented amount of control work was conducted both in Willapa Bay and Puget Sound, which has resulted in some real successes. In 2007, an estimated 2310 acres of spartina, comprising 99 percent of the total infestation, were treated in Willapa Bay. We expect fewer than 1150 acres to remain at the start of the 2008 season.
Treatment of Spartina in Willapa Bay — (35KB PDF)
Photograph 1 — (214KB PDF)
Before and after of Spartina alterniflora in Potshot Slough, located in south Willapa Bay across from Long Island. This 200-acre slough is shown as it was completely infested in July 1998, and eradicated in July 2006.
Photograph 2 — (1167KB PDF)
Before and after of Spartina alterniflora in Seal Slough, located in close proximity to the Nemah River. This 400-acre slough is shown as it was completely infested in August 2003, and nearly eradicated in August 2007.
Aerial Photograph with GIS Overlay — (3148KB PDF)
Image shows part of the Naselle River, located in south Willapa Bay, with GIS coverages of spartina in 2000 and 2006. The spartina as it appeared from the air in 2000 is depicted in yellow; the spartina as it was in 2006 is depicted in red.