Executive Order 13112 Ð defines an invasive species as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.”
Some non-native species, for example West Nile virus, are considered invasive and undesirable by virtually everyone. Other non-native species are not as easily characterized. For example, some are considered harmful, and therefore, invasive by some sectors of society while other sectors consider those species to be beneficial. This discontinuity is reflective of the different value systems operating in our free society, and contributes to the complexity of defining the term invasive species. These uncertainties have stood and could continue to stand in the way of progress in actions and policy development to prevent new invasions and manage existing invasive species. In 2006, the federal Invasive Species Advisory Committee submitted to the National Invasive Species Council an Invasive Species Definitions and Guidance white paper that provides a non-regulatory policy interpretation of the term invasive species. The white paper identifies what is meant, and just as important, what is not meant by invasive species. The discussion applies equally to all taxa of invasive species in all habitats and provides insight into those areas where societal judgments will be necessary to implement effective invasive species public policy.