Exotic Invasive Plant Species Control

Exotic Invasive species’ management is important to protect the Park’s landscape and to comply with the Executive Order on Invasive Species.

What are exotic invasive plant species? An exotic, invasive species is not native to an area and displaces native species. Take kudzu as an example: a highly vigorous and adaptive species from Japan, kudzu brought to stabilize slopes now pours down hillsides, choking out native plants by blocking light and using up soil nutrients and water. Over time, exotic invasive species such as kudzu change plant communities and sometimes entire ecosystems.

How big is the problem? Where do exotic plants come from? In the Great Smoky Mountains, scientists have counted 350 exotic plant species. They come from a few sources:

• Pre-Park home-site landscaping
• Gravel and topsoil brought into the park
• Visitors’ shoes, tires, and floormats
• Animal and wind deposition, especially following fires in the park

Of the 350 species, the park actively controls 50—the ones that are exotic AND invasive. These include kudzu, multiflora rose, coltsfoot, and garlic mustard, plants that will take over native species’ habitat and thereby alter the food chain, fire regimes, and biodiversity.

How are they controlled? The park’s exotic plant treatment program has deep roots. Beginning in the 1940s and 1950s, the park was already treating kudzu and multiflora rose. In the 1980s vegetation managers mapped and documented several exotic, invasive species, and since the 1990s the park has had a successful program combining chemical and manual control, as well as prevention of new plant introductions. When possible, vegetation managers pull or cut invasive exotic plants. When this isn’t practical, they spray selective herbicides or cut trees and paint the stumps with herbicide.

Does management work? With persistence, yes. Because Great Smoky Mountains National Park began its invasive species control program early, it has fewer rampant exotic populations than do other parks of the same size. The program involves systemic treatment, beginning with thorough surveys, accurate documentation and mapping, best management practices for control, and consistent monitoring and re-treatment. Volunteers often work in conjunction with managers so efforts can continue all over the park. You can read more the successful control of one invasive exotic species, kudzu, in an upcoming “Dispatches.”

Click here to return to Meet the Managers: Issue 1.