What is being done?

Overview What Is a Non-Native? Why Are We Concerned? What Is Being Done? What Can I Do? Our Most Invasive Plants Reports and Species Lists Links Home

Plants Bull Thistle Cheatgrass Foxglove French Broom Giant Reed Greater Periwinkle Himalayan Blackberry Italian Thistle Reed Canary Grass Spanish Broom Velvet Grass Yellow Star Thistle

 

Prior to 2001, non-native plant management in Sequoia and Kings Canyon National Parks was conducted on an ad hoc basis by park staff and volunteers. In 2001, funds to begin a restoration and non-native plant management program became available.

Also in 2001, the Biological Resources Division of the U.S. Geological Survey published a report detailing the invasive potential and management priority for each non-native plant species in the parks. The park cannot feasibly manage all its invasive plants, so the most threatening and/or easy to control species must be prioritized. This report gave the parks the information necessary to begin management.

 

Prevention

Non-native plants are continuously introduced and spread around in the parks. Preventing this movement of non-native plants is the first line of defense in protecting ecosystems from degradation. It is also the most economical and efficient means of management.

Seeds of non-native plants travel wherever soil is moved--in the treads of car tires, bicycle tires, and shoes. Soil, sand, or gravel imported for construction or other management reasons can also contain non-native plant seeds. Many non-natives have hook-like seed coats and arrive in the park stuck to the fur of pets, wildlife, and pack stock or on people’s clothing, shoelaces, and camping gear. Seeds can blow in from the gardens of neighboring private landowners or can wash downstream in rivers. Hay used to feed horses or straw used in revegetation projects can contain non-native plant seeds from the field in which the hay was grown.

The park is beginning to implement measures to prevent the introduction and spread of non-native plants. To successfully do this, many constituencies will need to become active and informed, including NPS staff, the visiting public, concessioners, permittees, contractors, and partners.

 

NPS Photo

NPS personnel removed greater periwinkle (Vinca major) from Potwisha Campground in 2001. Black plastic bags full of greater periwinkle are visible in the background; this plant material will be safely disposed of offsite.

Detection

Early detection of invasions is essential to effective, low-cost control. Detection of new invasions in the parks is conducted by surveying recent disturbances for invasive weeds. These early detection surveys may be species based, such as surveying the recently disturbed Generals Highway corridor for the highly invasive yellow star thistle, or location based, such as surveying recent, high intensity fires in natural areas for weeds. A database of non-native plant observations has been developed and is continually updated with input from park staff, concessioners, and visitors. Observation forms are available at visitor centers for recording weed sightings.

Control

The species chosen for control are those that have the highest impact on the ecosystem and can be controlled with the least effort (for more information about selection criteria, see the report Exotic species threat assessment in Sequoia, Kings Canyon and Yosemite National Parks). For more information on some of our top invaders, see our most invasive plants pages. Certain plant communities are prioritized over others. Native, pristine communities have the highest priority for management, while altered but relatively naturally functioning communities such as foothills grasslands have lower priority. Sometimes the goal is eradication (complete removal of the species from the park), while other times the goal is containment (containing an infestation within its current boundaries and preventing further spread). Knowledge of a species' aerial extent is necessary for effective control and monitoring. Therefore, mapping of non-native species is carried out prior to and during control.

Most eradication efforts are done by hand or with tools such as weed wrenches and shovels. Herbicides are used only when other alternatives have been considered and eliminated, and when managers are confident that the proposed herbicide will do more ecological good than harm and will not endanger the health of the applicators or others in the area. Treatments are highly targeted, minimizing the drift of herbicides to non-target plants, and the principles of integrated pest management are followed.

Education

For prevention or management efforts to be successful, the public must: (1) understand the threats posed by invasive plants, (2) change behavior that results in the spread of invasive plants, and (3) provide support for management efforts.

A newsletter, invasive plant observation cards, and this web site have been developed to provide outreach materials to the public. Park staff is being trained to identify priority invasive plants and to inform the public about invasive plant issues.

We are working with local communities, especially private landowners within the larger boundary of the park, to encourage the use of native plants to replace invasive landscaping. A plant exchange project is currently underway, in which the park provides showy native plants of local genetic stock in exchange for the residents' removal of their invasive plants.

The park has developed a policy to prevent the introduction and spread of non-native plants and is beginning to implement these Best Management Practices. To successfully do this, many constituencies are becoming active and informed, including NPS staff, the visiting public, concessioners, permittees, contractors, and partners.