Undesirable Non-indigenous Species

ARCHIVE: This page no longer being updated.  It is made available for historical reference. (12/20/99)

The Western Governors’ Association is developing a new program to address undesirable non-indigenous aquatic and terrestrial species in the West because of the significant economic and ecological harm they cause.  On June 30, 1998, the Western Governors passed Resolution 98-018, Undesirable Aquatic and Terrestrial Species, to develop and coordinate Wetern strategies and to support management actions to control and prevent the spread and introduction of  undesirable species; to support the use of Integrated Pest Management concepts; to encourage broad-based partnerships; and to urge adequate support for the U.S. Department of Agriculture - Animal and Plant Health Inspection Service.  WGA has formed a working group of  state and  federal agencies, industry, non governmental organizations and academia to develop Western strategies to limit the spread of these species.

Economic and Ecological Impacts

The economic and ecological impacts of undesirable aquatic and terrestrial species in the United States are significant and growing rapidly.  Estimates vary, but the annual price tag could run as high as $122 billion.  Among the examples are:

• Total costs of introduced weeds on U.S. crops is about $29 billion. This is based on an estimated 12 percent reduction in crop yield, 73% of which is attributable to non-indigenous weeds, and on $3 billion spent for herbicides.
• Homeowners and golf courses spend about $500 million and $1 billion respectively annually on non-indigenous species weed control.
• Approximately 360 non-indigenous insect species established in American forests cause losses of more than $2 billion annually.
• Zebra mussels clog water intake pipes at water filtration and electric generating plants, costing an estimated $3 billion for control and cleaning.

The impacts of undesirable non-indigenous species on the health of the environment is equally dramatic and troublesome. It is probably not an exaggeration to say that many of the conservation gains this nation achieved over the last few decades are at risk due to undesirable non-indigenous species. Non-indigenous species are implicated in the decline of 42 percent of the species listed under the Endangered Species Act.  Some refer to the invasion of non-indigenous species as biological pollution and note that their impact on the world’s biota is likely greater than climate change or decreasing stratospheric ozone levels.

When first confronting the devastating economic and ecological impact of undesirable, non-indigenous species, it is easy to feel overwhelmed. But it is important to keep several things in mind. First, even though noxious weeds are invading 4,600 acres of federal lands in the West every day, more than 90 percent of those lands are largely unaffected.  Second, even though aquatic species such as the zebra mussel and mitten crab are causing disastrous impacts where they are established and are threatening to spread, the opportunity still exists to stem the spread and prevent significant impacts in many other areas of the nation. Third, even though there are more undesirable non-indigenous species in this country than anyone would like, effective steps can be taken to keep out many more waiting to get in. WGA believes effective strategies can be developed by working in partnership with others and developing priorities based on consensus, as described in WGA's Enlibra doctrine.