by
Union of Concerned Scientists
A new study shows that screening for potentially harmful foreign plant species before they are imported is more economically beneficial than fighting them after they take root in new areas. Because the United States has no screening program for invasive species, the study focuses on Australia and finds that their prevention efforts pay for themselves with reduced economic damage in just over ten years and result in up to $1.8 billion in savings over 50 years.
"Because our plant industry is several times the size of Australia's - and because these figures are conservative - the U.S. could save even more if we began to screen plants before they are imported," said Phyllis Windle, Senior Scientist and director of invasive species work at the Union of Concerned Scientists. "From any country's perspective, it's better to fight invasives species over there instead of over here."
About 85 percent of non-native woody plant species growing wild in the U.S. were originally imported for the landscaping and nursery trade. Because the U.S. allows imports regardless of invasiveness, many species make it to public and private lands undetected. Once invasives take root, controlling a single species can cost millions of dollars annually because eradication is often impossible.
Florida, for example, has spent about $8.2 million since 1998 to limit the spread of Old World climbing ferns in public lands. These plants were introduced as ornamentals and serve as "flame ladders" during fires. Many other horticultural imports, like English ivy, Brazilian pepper, bush honeysuckles, and Norway maple, also have high environmental costs when they displace native wildflowers, decrease wildlife habitat, or change the availability of water or sunlight.
The Australian program is 90 percent effective at identifying and preventing potentially harmful imports of plant species. Overall, 25,360 foreign plant species have been introduced to Australia and 1,366 (5 percent) have become invasive and caused economic harm. Of these, 70 percent were imported for the ornamental plant trade, a $3.9 billion industry in Australia. The annual economic damage from ornamental invasive plants in Australia is over $2 billion. Meanwhile, administrative costs for Australia's screening program are estimated at only $213,000 per year.
"Invasive plants spread for decades and their economic and environmental costs are severe and increasing," said biologist David M. Lodge of the University of Notre Dame, one of the study's authors. "Even when we only considered very straightforward costs, it's clear that screening benefits both the economy and the environment. Screening is the next step in improving U.S. policy and completely consistent with our international trade obligations."
Often, the costs of invasives species are borne by taxpayers, as in the Great Lakes, where the U.S. and Canadian governments together have spent about $15 million annually since 1956, controlling sea lampreys. In 2003, Federal and state agencies spent more than $14 million to slow the spread of European gypsy moths along a ten state line. And West Nile Virus has killed hundreds of Americans, sickened thousands of others, and affected more than 200 species of native birds. Altogether, invasive plant and animal species have caused billions in economic harm in the U.S.
This study is the first to analyze the net economic benefits of a screening program. While few countries require screening for invasive species, many nations suffer from invasive species that increasingly make their way to new countries through growing global trade.
"Invasive species policy in the U.S. is way behind the curve," said Windle. "This should be a wake up call to Congress and the U.S. Department of Agriculture that strong, new legislation and regulation are long overdue."
The study was written by Reuben P. Keller and David M. Lodge, biologists at the University of Notre Dame, and David. C. Finnoff, an economist with the University of Wyoming. It will be published in the Proceedings of the National Academy of Sciences this week.YubaNet
