Invasive Species Control

Four basic strategies are available for solving exotic species problems: prevention, eradication, suppression, and biological control.

1. Prevention is the identification and interdiction of exotic species or their propagules before they enter the United States.
2. Eradication is the complete elimination of a population of an introduced exotic. It is effective against relatively small, localized infestations but requires intense effort and may be relatively expensive. In the case of plants, extensive and repeated use of herbicides is usually necessary, and some injury to desirable plants or the surrounding environment may be unavoidable. Eradication of large, well-established populations usually is not feasible.
3. Suppression is the periodic control or elimination of a population of exotics within a generally infested area. Suppression offers only a temporary solution to the exotic problem, and generally must be repeated at regular intervals. It generally becomes a permanent maintenance project unless biological control can be established.
4. Biological control involves the identification and introduction of an exotic species' natural control agents, usually herbivores, predators, parasites, or pathogens from its native environment. This is an expensive and time-consuming process because extensive research must be conducted to ensure that the proposed control agent will not cause further problems in its new environment. Biological control, if successful, brings the exotic species into balance with its environment so that it continues to be a component of the plant community but will not dominate it. However, biological control is not always possible or practical. (SAMAB 1996e).

Control of invasive species in the the Southern Appalachians

Control of exotic species on public land is complicated by the patchwork of jurisdictions; national parks, national forests, state, and private lands vary considerably in their approach to exotic species control. Of federal lands in the Southern Appalachians, only national parks have programs to control exotic plants. Approximately 40 invasive plant species are currently controlled in national parks in the region. Land managers cite the lack of money and personnel as the most serious immediate impediments to control. Although land managers are aware of the problem, addressing it will be difficult without additional resources (SAMAB 2001).

National forests in the Southern Appalachians have generally not attempted to control exotic plants except for kudzu, which has serious localized impacts on forestry. In fact, nonnative plants such as crown vetch, lespedezas, white dutch clover, and tall fescue were commonly planted for erosion control after timber harvests and road construction, or as food for wildlife. Today, attempts are made to use native plants for these applications. Other exotics, such as privet, threaten to become problems in spots on national forests. Where national parks adjoin national forests and other federal and state ownerships, uncontrolled infestations of exotic plants often cross boundaries and create continuing management problems for the parks (SAMAB 2001).

In recent years, the Federal Government has increased support for the control of invasive species. On February 3,1999, President Clinton signed an Executive Order (#13112) to strengthen the control of invasive species by preventing introductions, minimizing damaging effects of invasive species, monitoring invasive species populations, conducting research, and restoring ecosystems and habitats (USDA Forest Service 2000).