Preventing invasion
Milk Thistle may help generate a great dietary supplement for humans, when processed properly, but it can be toxic to livestock and is native to Western Asia, Europe and Northern Africa. State authorities are asking that campers and hikers clean themselves, their pets and their gear to ensure seeds from such plants aren’t carried home after an outdoors outing, thus increasing the spread of the invasive species.
COURTESY PHOTO/WASHINGTON STATE NOXIOUS WEED CONTROL BOARD
OLYMPIA — State agencies are asking people to clean up their gear, pets and clothing to prevent invasive plants from establishing here, according to a statement from the Washington State Recreation and Conservation Office.
State law requires landowners to control noxious weeds when they are present on their properties, the statement said, but when people are coming and going on public lands, that’s not completely possible.
“Preventing noxious weeds is as simple as remembering to clean your boots, pets and equipment before you recreate so you aren’t bringing a biological hitchhiker with you from home to your favorite trail or meadow,” Mary Fee, executive secretary of the Washington State Noxious Weed Control Board, wrote in the statement. “It is equally important to clean everything and everyone once you are finished so that you don’t bring a problem weed back home with you.”
A 2017 state report estimated that the top 22 priority invasive species, of more than 200 in the state, could cause more than $2 billion annually in economic and environmental impacts if left unchecked, the statement said.
Invasive species also can restrict access to recreation sites or prevent use of areas because of their presence and the damage they cause. A second state report from 2020 showed that outdoor recreation contributes $26.5 billion to Washington’s economy annually and supports 264,000 jobs, rivaling the state’s aerospace industry.
“Beyond economics, Washington’s public lands include a wide range of plants and animals that face risk of loss and possible extinction because of invasive species,” Joe Rocchio, Natural Heritage Program manager for the Washington Department of Natural Resources, wrote in the statement. “Invasive species are the primary threat to 25% of the state’s rare plant species and a significant threat to many of the state’s most imperiled ecological systems, including lowland prairies and oak woodlands in western Washington and shrub-steppe in the Columbia Basin.”
More information can be found at www.nwcb.wa.gov.