Invasive Aquatic Species

Quagga musselInvasive aquatic species have been in the news lately, and with good reason. They wreak havoc on lakes, rivers, streams and wetlands. For example, New Zealand mudsnails have been documented to replace 90% of the snail and insect population in a river bed within the first year after discovery. This has a negative effect on the food chain for fish, amphibians, and birds. Invasive aquatic species increase maintenance costs for levees, dams, dikes and other structures and can reduce economic value of some areas.

On National Forests in Region 6 (Oregon and Washington), the Forest Service is working together with other landowners and agencies to manage aquatic invasive species so that we can maintain the health of aquatic ecosystems. These efforts include prevention, early detection and rapid response, and control activities.

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Invasive Aquatics Management

The cornerstones of invasive species management are:

1. Prevention

Once introduced, aquatic invasive species may be impossible to control, so prevention their introduction is essential. We need the help of all visitors to our National Forests to prevent harmful changes to our aquatic habitats from invasive species.

2. Early Detection & Rapid Response (EDRR)

While prevention is the first line of defense, even the best prevention efforts will not stop all invasive species. Early detection and rapid response (EDRR) efforts increase the likelihood that invasions will be halted and eradicated. An effective EDRR program will greatly improve chances for success, minimize costs, and prevent harmful alterations to National Forest ecosystems.

  • How to Report Sightings of Invasive Species on National Forests

An example of R6 EDRR efforts:

3. Control

Forest Service control and management activities are founded on integrated pest management principles that may include a combination of physical or mechanical, biological, cultural, and chemical techniques. This integrated approach also includes assessments of risk, identification of thresholds for action, and planning to reach the most desired outcome. Unfortunately, for many aquatic invasive species, like mussels, snails, crayfish, and crabs, there are no effective control techniques.

Aquatic invasive plants and invasive fish do have some effective control techniques, although control is still quite challenging.

Invasive Fish

  • In the Pacific Northwest region, projects to control of invasive fish are generally proposed by the respective State Department of Fish and Wildlife while the Forest Service is a partner.  One such project was conducted in 2006 at Diamond Lake on the Umpqua National Forest: Diamond Lake tui chub removal

Invasive Plants

  • Invasive aquatic plants are generally treated by manual and cultural methods, such as pulling, raking, and sometimes covering the bottom with heavy tarps.
4. Inventory and Monitoring