Nonnative Nuisance

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Published on: Apr. 2, 2006

Last revision: Nov. 23, 2010

In the summer of 2003, I was a hired gun for the Illinois Exotic Species Task Force. My primary mission was simple: eradicate populations of kudzu (Pueraria lobata). This invasive exotic plant was responsible for consuming millions of acres of forestland across the Deep South in a veil of jungle-like vines.

My mission took me across the state of Illinois and up against urban infestations in Peoria to “Kudzu Mountain” in the Shawnee Hills. My job was to protect our natural resources from exotic plants and animals. When I came to Missouri, I brought my work with me.

Know your enemy

Exotic (or “nonnative”) species are those that didn’t exist here before European settlement within the state’s present boundaries. An invasive exotic species is one that is likely to cause harm to the economy, the environment or to human health.

There are many exotics within the state, but only a rebellious few cause problems within Missouri’s ecosystems. Roughly 28 percent of Missouri’s flora is made up of exotic plants introduced to the state, while only 4 percent are considered invasive.

The invasive exotics are ranked (from high to low priority) as highly invasive, moderately invasive, widespread, or locally invasive. Highly invasive species are of most concern because they reproduce prolifically and compete aggressively. They can replace or exclude native species because they are not held in check by the natural pressures of predation, disease or competition that kept them in check in their native habitats.

Invasive species include a variety of exotic plants, insects, fish, mollusks, crustaceans, mammals, birds, reptiles, amphibians and pathogens. They threaten what we as Missourians hold dear—our fisheries, forests, wetlands, prairies and wildlife. Invasives account for damages and losses totaling approximately $137 billion each year in the U.S. They damage our ecosystems, push out native organisms, and alter our landscapes. Approximately 400 of the 958 species recognized as threatened or endangered by the Endangered Species Act are declining due to competition with invasive species.

By land, sea and air

Invasive exotics are transported from ecosystem to ecosystem both intentionally and unintentionally. Purchasing an invasive plant such as a burning bush, purple loosestrife or a bush honeysuckle and transplanting it into your yard is an example of an intentional introduction. So is knowingly transporting invasive seeds, whole plants or cuttings, live animals or pathogens with the intent to establish, maintain or release them into a new area.

Invasives are introduced unintentionally when gypsy moth egg masses are

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