Invasive Species Control

The Department of Natural Resources (DNR) is committed to protecting aquatic lands from the harmful effects of invasive species. To this end, DNR has increased its effort to control noxious weeds on state-owned aquatic lands. The vision of the program involves the following elements:
  • Preserving the value and ecological integrity of unaffected and minimally affected state-owned aquatic lands by eliminating small noxious weed infestations.
  • Eradicating or reducing large-scale infestations to a size that no longer threaten wildlife habitat, native plants, industry, and other human values.
  • Restoring aquatic lands where possible.
DNR has management responsibilities to control noxious weeds on state-owned aquatic lands. Many of these weeds have been introduced to Washington as ornamental plants (purple loosestrife, giant hogweed), water garden plants (parrot feather milfoil), aquarium plants (Eurasian watermilfoil, Brazilian elodea, fanwort), shipping material (smooth cordgrass), and erosion control plants (common cordgrass). The plants have then escaped into our waterbodies, displacing native species and altering the physical and hydrologic conditions found naturally.
Within the approximately 2.6 million acres of aquatic lands that DNR manages, noxious weeds are present in marine, estuarine, and freshwater conditions. 
Throughout the marine waters of Puget Sound, the kelp Sargassum muticum is found in lower intertidal and shallow subtidal rocky habitats displacing the native macroalgae. 
In our estuaries, invasive Spartina species (i.e., S. alterniflora, S. anglica, S. densiflora, S. patens) have become well established and are rapidly raising tidal elevations, displacing eelgrass and native marsh plants, and reducing habitat for migratory waterfowl, invertebrates, and possibly fish. 
In our lakes and streams, numerous invasive species are present, such as purple loosestrife, Brazilian elodea, and parrotfeather, and these, also, are outcompeting native plants and reducing habitat for wildlife. 
To maximize our efforts, DNR has joined forces with other agencies and organizations on weed control projects. Some of these projects (and partners) include Spartina Eradication Project in Willapa Bay (WSDA, WDFW, USFWS, UW, WSU, TNC, PCSGA), Brazilian elodea removal in the Chehalis River (Thurston County, Mason County), and knotweed control in the Stillaguamish and Skagit River watersheds (Stilly-Snohomish Fisheries Enhancement Task Force, TNC, Snohomish County, Skagit County).