Invasive Species: Noxious Weeds & Aquatics

An invasive species is defined as a plant, animal, or microbe, including its seeds, eggs, spores or other biological material that is non-native to the ecosystem under consideration and whose introduction causes, or is likely to cause, economic or environmental harm or harm to human health.

The goal of the US Forest Service invasive species program is to reduce, minimize, or eliminate the potential for introduction, establishment, spread, and impact of invasive species across all landscapes and ownership.

Intermountain Region's Invasive Species website

Aerial Application Information

Noxious Weeds

Photo of Spotted Knapweed.Noxious weeds are undesirable exotic plant species which have the ability, due to their invasive nature, to significantly affect entire ecological watersheds, physically alter the environment, and impact visitor’s experiences. Noxious weeds have a direct influence on biodiversity. They affect plant species diversity by displacing native and desirable plant communities, and impact fish and wildlife populations supported by those communities.

Noxious weeds can displace native plants, interfere with land and water use, and affect human and animal health. Weeds not native to an area are of special concern because there are no natural or ecological controls, such as insects or disease, to limit their spread.

In addition to impacting literally all of the plant and animal communities within the area, infestations of noxious weeds (particularly large ones) can greatly affect soil, watershed stability and erosion rates. Noxious weeds can also change normal fire patterns and other big picture ecosystem functions such as nutrient cycling.

Noxious weeds can also change normal fire patterns and other big picture ecosystem functions such as nutrient cycling that directly affect the Frank Church – River of No Return Wilderness and Wild and Scenic Rivers.

The size and extent of noxious weed infestations within the Middle Fork of Salmon corridor may directly or indirectly affect:

  • The number of clear water days, which effects both fishing and navigation.
  • The amount and types of wildlife seen in the river corridor.
  • The amount and quality of areas suitable for camping.
  • The number and diversity of flowering plants observed.
  • Size, extent and frequency of tributary blowouts.

There are several noxious weed species present in the river corridor. Rush Skeletonweed (Chondrilla juncea) and Spotted Knapweed (Centaurea maculosa) currently are the most aggressive and pose the greatest threat. The USDA Forest Service in conjunction with various partners manages these and other noxious weed species in the river corridor utilizing an Integrated Weed Management strategy. The Middle Fork Ranger District can provide additional information about noxious weed infestations and species within the river corridor, the Integrated Weed Management strategy and ongoing partnerships.

What you can do to help:

  • Learn to identify noxious weed species that occupy lands in the areas where you live and recreate.
  • Clean your clothing and equipment prior to and directly after use in areas with noxious weeds to prevent the spread of weed seed to new areas.
  • Avoid traveling through or camping in areas infested with weeds.
  • Report sightings of noxious weeds.

Noxious weed free hay in Idaho

Aquatic Invasive Species (AIS)

Photo of a Zebra mussel.  Credit: Utah Division of Wildlife Resources.AIS are spreading rapidly across the nation, choking rivers, streams, lakes and reservoirs. Cleaning all equipment thoroughly and allowing time to dry between water bodies is key to reducing the spread of these organisms.

What’s on the list and what does it look like? Click here to visit our Region’s web page.

More information sources:

USDA Forest Service Invasive Species Program

Intermountain Region Natural Resources

National Invasive Species Information Center

Welcome To the Idaho Weed Awareness Campaign!

Pacific Northwest Weed Management Handbook: An excellent source of information about invasive species, invasive species management techniques, and herbicide use.

Idaho Weed Awareness Campaign

Idaho’s Noxious Weeds List

Idaho's Invasive Species Program

National Invasive Species Information Center

Salmon-Challis National Forest contacts:

Tina Ruffing, Program Manager - - (208) 756-5125

Diane Schuldt, North Zone (Salmon) - - (208) 756-5249

Tommy Gionet, South Zone (Challis) - - (208) 879-4116


  • Salmon-Challis Forestwide Integrated Weed Management Link opens in a new window
    Implement adaptive and integrated invasive plant management on current and potential infested areas which would include inventory and assessment designed to support Early Detection Rapid Response, control methods, monitoring, and rehabilitation.