Salvinia_molesta (Giant Salvinia)
Photo by J. M. Hyde

For the last couple of decades the U.S. has actively worked to reduce the environmental pollution of the air, water, and soil. There have been many success stories reported once a source of pollution is identified and treated or stopped. Invasive species are another form of environmental pollution, biological pollution. When the source of this pollution has been found and treated or stopped, you have not solved the problem. Everywhere this biological pollution spreads, the living biological pollutants multiply and serve as new sources of additional pollution.

There have been tens of thousands of plant or animal species introduced from other countries, but few ever become invasive species. Those species that truly become invasive place an ever increasing economic burden on the citizens of the U.S. An excellent overview of the problems caused by invasive species was presented in the

Office of Technical Assessment’s report: Harmful Non-Indigenous Species in the United States