Exotic and Invasive Species
Invasive species have been characterized as a "catastrophic wildfire in slow motion." Thousands of non-native invasive plants, insects, fish, mollusks, crustaceans, pathogens, mammals, birds, reptiles, and amphibians have infested hundreds of millions of acres of land and water across the Nation, causing massive disruptions in ecosystem function, reducing biodiversity, and degrading ecosystem health in our Nation's forests, prairies, mountains, wetlands, rivers, and oceans. Invasive organisms affect the health of not only the Nation's forests and rangelands but also of wildlife, livestock, fish, and humans.
The White Mountain National Forest and the entire White Mountain region is fortunate that infestation levels of invasive plants and animals are relatively low. Many species which are widespread throughout the New England and the northeast are not yet well established in the White Mountain region. The White Mountain National Forest is undertaking effective prevention and control measures to minimize the impact of these introduced species on the landscape. One key element of this program is the White Mountain Early Detection Network. This network of conservation professionals is working to identify new incursions of invasive species early in the invasion cycle when they can be more successfully eradicated.
A species is considered invasive if it meets these two criteria:
- It is nonnative to the ecosystem under consideration, and
- Its introduction causes or is likely to cause economic or environmental harm or harm to human health.
Invasive species are introduced in many different ways many accidentally and others intentionally before the species was determined to be invasive. Purple loosestrife was originally introduced via seeds contained in the soil used as ship ballast. Japanese barberry was originally and in many locations today sold as a horticultural plant. Japanese knotweed was widely promoted for soil conservation measures to control bank erosion along rivers and streams.
Invasive species arrive at their introduced locations with none of the diseases or predators that control their rapid growth and spread in their native range. This lack of natural control allows them to reproduce freely and easily, spreading from the point of introduction into native ecosystems. Once established in these areas, they quickly displace native species and alter plant and wildlife relationships.
The impact of these species is often measured in ecological terms, but the economic costs, often more difficult to determine, are staggering. It is estimated that each year, more than $138,000,000 of the United States' economic output is lost through decreased agricultural yields and recreational revenue, or expended on research and control efforts.