System Battles Invasive Species

Citizen support is key to helping National Wildlife Refuge System maintain lands.

Orange Hawkweed

Orange Hawkweed

Courtesy U.S Fish and Wildlife Service

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Invasive plants and animals – introduced to the lands and waters of the United States from foreign shores – continue to plague national wildlife refuges. Some efforts to stem this threat are already in place and beginning to take hold. But there are other steps you can take to help.

About 2.4 million acres of the 98-million-acre National Wildlife Refuge System are currently infested with invasive plants, according to the 2007 Refuge Annual Performance Plan. Additionally, 4,423 invasive animal populations occupy refuge lands – from the brown treesnake overrunning Guam National Wildlife Refuge to the more common nutria, a species that has spread to many states that was brought from South America when its fur was highly marketable.

National wildlife refuges spent more than $11 million last fiscal year in fighting this problem, which has become pervasive. During each of the past four years, the Refuge System has treated an average of 14 percent of the acres infested with invasive plants.   

Citizen support is key in the battle against invasive species. The Refuge System has worked for the past three years with the National Wildlife Refuge Association, The Nature Conservancy and the National Institute of Invasive Species Science on a program that has enabled about 2,750 volunteers to inventory, treat and restore more than 211,000 acres of Refuge System land. 

Many of these refuge volunteers are called upon to wage hand-to-hand combat with invasives. At Silvio O. Conte National Fish and Wildlife Refuge, the New England Invasive Plant Group – a network of agencies and organizations working with the refuge – fought the water chestnut. The aquatic invasive floats on the water’s surface and displaces native plants. The infestation at Log Pond Cove was first detected in 1997, not long after the refuge was established. Once the plant is well established, eradication is next to impossible.

Silvio O. Conte Refuge began to show progress in controlling the problem only after it enlisted the help of hundreds of volunteers to hand-pull the weed, year after year. Machine pulling was not doing the job.

How Citizens Can Help

In collaboration with the Center for Invasive Plant Management, the National Wildlife Refuge System has designed an online training course for volunteers and others interested in joining the army to help fight invasive plant species – one of the single greatest threats to the Refuge System. The new Web-based training course,, includes video, text and photos that provide information about the science and management of invasive plants.

In Fishing Season: 

? Don’t dump any bait, especially minnows or crayfish, into streams or lakes after fishing. 

? Be sure to inspect and thoroughly clean your fishing gear, including boats, trailers and waders. Invasive plants and animals, like hydrilla and zebra mussels, can quickly spread to uninfested waters by hitchhiking on gear used by anglers.

In the Garden: 

? When looking for ornamental plants or groundcover for your home or garden, use native plants. Many areas now have nurseries specializing in local native plants, or search online for your local native plant society that can make recommendations for you. 

If you do use a non-native plant, ask your local nursery if it is an invasive species in your area.

When buying a potted plant, check for unwanted weeds growing in the pot and make sure to pull them out before planting. 

When you pull unwanted weeds out of your lawn or garden, make sure to remove the entire plant and carefully bag it for disposal. Seeds from a dying plant can spread into uninfested areas.    

Volunteer on a National Wildlife Refuge: More than 36,600 people already donate their time to national wildlife refuges. To join this outpouring of public concern for public lands – whether to fight invasive species or help in other ways – find information about volunteering on the Web at

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. They are both a leader and trusted partner in fish and wildlife conservation, known for scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on their work and the people who make it happen, visit