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Expert calls weeds major problem for ecosystem Spotted knapweed could spread without control, specialist says YELLOWSTONE NATIONAL PARK, Wyo. (AP) - The single biggest threat to the Greater Yellowstone ecosystem is a type of weed from southeast Asia called the spotted knapweed, a weed expert said. Tom Whitson, a weed specialist for the University of Wyoming, said the spotted knapweed covers about 50 acres in Grand Teton and Yellowstone national parks. The weed could spread further if it is not controlled, he said. Five million acres of rangeland in Montana already are being suffocated by the weed. "If we ignore the spotted knapweed we'll have thousands of acres that look like Montana," he said. Whitson spoke during a recent meeting of the Jackson Hole Weed Management Association, which aims to call attention to the growing problem of noxious weeds in Jackson Hole. Experts said it is not possible to get rid of noxious weeds, but their growth can be contained with herbicides, weed-killing insects and other methods. Since 1978, Wyoming has spent $30 million to limit the spread of leafy spurge, a large perennial with yellow flowers that can kill cattle. Despite those efforts, leafy spurge has spread from 50 acres to about 60,000 over the past 20 years. But without that effort, the spread of leafy spurge would be astronomical, Whitson said. As an example of how weeds destroy biodiversity, a study of 200 acres in central Wyoming choked with spotted knapweed revealed only one species of mouse living in the area, he said. Weeds were probably introduced by pioneers, the livestock industry, vehicles, pets, wind, water and a host of other transports, Whitson said. Noxious weeds push out desirable vegetation for wildlife and humans, and can even be deadly for livestock. For example, the houndstongue affects the liver in livestock and can kill an animal in six months. "The worst decision that can be made is to do nothing," Whitson said. Copyright 1999 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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