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		Nature Conservancy Magazine: Autumn 2007 Nature Conservancy Magazine Flora & Fauna Prairie Revival Amazon Harvest Subscribe Previous Issues

Unwanted Guests Water Hyacinth This prolific South American ornamental (above left) was introduced in the 1800s. Since then, it has been clogging waterways in the South and choking out native species. Zebra Mussel This Eurasian native (above middle) has caused billions of dollars of damage in the United States. It clogs water intake valves on power plants and can overwhelm native mollusks. Asian Longhorned Beetle This Chinese native (above right) has hitched rides to U.S. ports in wooden shipping crates. Its appetite for maple, elm and other hardwoods is a threat to backyard trees and the timber and maplesyrup industries. Go Deeper How can the United States thwart invasives? Learn about our new recommendations to keep potential invasives on their own turf.

The United States could save billions of dollars by stopping invasive plants and animals at the border, according to a new study in the Proceedings of the National Academies of Sciences. The study found Australia’s programs to screen out non-native pests—especially those that damage forests and crops—paid for themselves in just a decade.  That country stands to save $1.8 billion over 50 years.

A similar program in the United States “would yield significant economic benefits,” says John Randall, who directs The Nature Conservancy’s work on invasive species. About 2.5 billion live plants are imported into the country each year and are often sold to the public at garden centers. Inadequate inspection regimes have allowed these plants to serve as a path for hitchhiking pests and pathogens to reach U.S. forests and croplands.

—Curtis Runyan

 

Nature picture credits (left to right): Illustrations © Rachel Rogge (water hyacinth); © Gina Mikel (zebra mussel); © USFS (Asian longhorned beetle)