U.S. Geological Survey
The spread of invasive plants, animals and pathogens is considered one of the most serious ecological problems facing our nation in the 21st century, second only
to habitat destruction. These species include plants, animals, and microbes that have been introduced into an environment where they did not evolve and often have no natural enemies to limit their reproduction and spread--frequently at the expense of native plants and animals and, sometimes, of entire ecosystems.
Many invaders cause huge losses in agriculture, livestock, fisheries, and other resource production systems. Some significantly alter ecosystems, resulting in costly damages due to increases in fire, flooding, and erosion. A few are vectors, or carriers, of human diseases.
Unfortunately, invaders often go unnoticed until they have spread to many locations, making eradication difficult. Early detection and rapid response to invasions are essential if we are to prevent major damage to the health of our ecosystems and economy--an ounce of prevention is truly worth a pound of cure.
Invasive species are a growing threat to the Department of the Interior's stewardship of the Nation's natural resources. They are currently estimated to infest more than 30 percent of the acreage of the National Park System in the lower 48 states. By various estimates, these species contribute to the decline of 35 to 46 percent of U.S. endangered and threatened species.
In some regions, entire ecosystems are being transformed. In the Intermountain West, invasive plants such as cheatgrass are increasing the frequency and intensity of fire, replacing native species, and damaging rangeland values on our public lands. Aquatic invaders, such as the zebra mussel, Asian clam, giant salvinia, and purple loosestrife are transforming our wetlands and inland waters and reducing their value for recreation and wildlife. The threats have reached crisis proportions.
In his executive Order on Invasive Species, the President called upon federal agencies to coordinate their efforts to address this growing threat. A national invasive species management plan is being prepared, and the Department will play a key role. We must use our many capabilities to educate the public, develop the information and tools we need, and create partnerships, with those who can help us develop a coordinated national strategy. But to do this, we must first educate ourselves and become committed participants.