Many invasive species get a foothold due to human intervention, scientists say. Some species are simply hitchhikers, tagging along with humans and our cargo as we hopscotch around the globe. Given the pressures on remaining ecosystems, some worry that invasive species may even alter the course of evolution. Eradicating invasive populations once they are established can be so difficult and damaging to native neighbors that every state in the nation has been asked to develop a formal method of preventing, identifying and stopping invasions before they take hold. President Clinton created a national Invasive Species Council last February to oversee that effort.
Countries use trade policies to attempt to control the importation of diseases and unwanted species.
Agriculturists and natural resource managers frequently must rely on chemical controls for established invasions, and pass along to the consumer the cost of herbicides and crop losses. The financial costs are staggering. Websites and other resources exist to inform gardeners, outdoors lovers and travelers about the problem and how to avoid adding to it. Visit the links page of the colloquium website or contact the Nature Conservancy, the Native Plant Society, the National Park Service, Oregon Sea Grant, or your county Extension agent.