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Weed War Out West


Noxious foreign weeds have invaded the American West, crowding out native species. They're causing economic problems for agriculture and destroying sites set aside by the federal government for recreation, native plants and wildlife. Hells Canyon, which forms the border between Idaho and Oregon, is just such a place. Government officials, environmental groups and cattle ranchers are working together in Hells Canyon to fight an unexpectedly big problem.

A metal jet boat with carries about 15 people zooms up the Snake River. The state of Oregon rises on the west, Idaho on the east. At almost 2,500 meters, Hells Canyon is the nation's deepest gorge and hard to explore, even on jet boats. Snowmelt from massive mountain ranges feeds the Snake and it's tributaries. Down here in the canyon it's as hot and as its name implies, but beautiful. Campers swim along shore while boaters ply the water for fish.

Hells Canyon was set aside as a National Recreation Area in 1975. The federally protected status ensured that no more dams would be built along the Snake River to change its flow and hurt salmon spawning. People didn't realize then that the biggest threat to the place would be weeds.

U.S. Forest Service official Kendell Clark of the Forest Service walks on along the shore and points to the fast spreading noxious weed Yellow Star Thistle. Its spiky flowers blanket the cliff walls on both sides of the canyon here. "Every value that this landscape was put aside for is going to disappear," he says. "This is a whole, different enemy. This is war. This is war."

It's an expensive war that's being fought in many locales all over the country. The Federal Interagency Weed Committee estimates these alien weeds cost U.S. agriculture $20 billion each year. Dave Nelson of the Idaho Cattle Association hopes a new bill before Congress will bring in more federal dollars for the weed war. "Eradicating weeds converts to dollars and cents for cowboys."

Most weeds that threaten native grasses in Hells Canyon arrived here decades ago from the Mediterranean … without the insects and other natural enemies that kept them in check in Europe. The weeds are spread by hunters, hikers, bikers, and off road vehicle users, who roam the uplands looking for game birds, elk, deer or big horn sheep.

Retired Agriculture Professor Arlie Eisley says birds and animals also contribute to the problem. "We see different kinds of animals like coyotes particularly, carrying weed seed in their fur and they migrate with the game herd," he says.

The Nature Conservancy of Idaho documented 380 wildlife species and 1,000 native plant species in Hells Canyon, many found nowhere else or on earth. Such bio-diversity comes from the volcanic geology and remarkable depth of Hells Canyon. From the river, the ecosystem transforms from salt desert, through grasslands up to pine and fir forests. Fifteen years ago, the Nature Conservancy bought land bordering the canyon because it contained rare plants like spaulding silene, now being considered for federal protection because of invasive weeds.

Trish Klair, the Conservancy's Science Director, stands in the shade of a tree lamenting past actions. "Our dirty laundry here is that someone did say, 'hey, you guys got a patch of weeds out there!' Well, that was 15 years ago, so we got a patch of weeds. We didn't know any better," she says. "Like so many of us we didn't know what could happen and so right while we have been here managing the land, the weeds exploded on us."

Hoping to stop this weed explosion, the Nature Conservancy joined with others in the weed war. Group members pull weeds by hand… but that only works on new plants. They also spray with chemical herbicides, despite those opponents who say spraying can also hurt the fragile desert landscape.

Linn Danley of the federal Bureau of Land Management, admits that sometimes spraying just doesn't work. She points to a patch of stout plants topped by pale yellow flowers. "I hate leafy spurge. This one site is two acres (almost a hectare) and we've been working on it for five or six years and spurge just keeps coming up outside the fringe of your herbicide treatment, we keep nuking shrubs out further each year."

So a different weapon was developed for those huge patches of weeds that can't be controlled with herbicides, bio-control measures. Jim White of Idaho Fish and Game, says scientists took the weeds' natural predators, mostly beetles and flies from the Mediterranean, raised them in nurseries here, then dropped the bugs from airplanes over remote sites in Hells Canyon. "We took coffee cups, we taped rocks to the bottom of them, we put bugs in coffee cups, and when we flew over a Star Thistle patch, we would drop those coffee cups onto that patch," he says.

But such bio-control measures can take up to twenty years to take effect. Dan Sharratt of Oregon's Agriculture Department surveys the insects' progress in one weed patch. "There's quite a bit of feeding damage from one of our biological control agents. You can see those little crooks where the tip of the stem has been tipped over," he says.

Mr. Sharrat's team helped developed five different insects that attack the stem, base and seed heads of star thistle, and 12 bugs that eat leafy spurge.

But Ric Bailey of the Hells Canyon Preservation Council is worried about this approach. "When you go tampering with the ecosystem by introducing non-native bugs to get rid of non-native weeds you really don't know where it all stops," he says.

In response, scientists say bugs evolve to eat just one or two kinds of plants, so probably pose little danger to the native species in the canyon.

Soldiers in the war on weeds may bicker about strategy, but the Bureau of Land Management's Linn Danley says they all share one overriding concern: "… finding the darn stuff …."

They've begun using satellite imagery to help them spot weeds in the rugged canyon. Then they. verify the location with a newly designed hand held computer. Matt Lucia of the Idaho Fish and Game explains that as a technician walks through Hells Canyon holding the computer, he downloads topographic maps on it, then notes exactly on those maps where he sees the weeds. "So all the information he's collecting in the field can be taken to the desk top computer," he says.

Then all the agencies and private citizens fighting the weeds war can check their office computers, find out where noxious plants are starting up and quickly kill them before they spread. But, as Trish Klaire of the Nature Conservancy observes, that might be the end of the battle but it's not the end of the war. "After we kill weeds, we gotta get something growing there or we just get more weeds back," she says.

So the Conservancy helped students collect seeds of the native Blue Bunch Wheat Grass and hired a local farmer to grow more grass seeds. Now 'weed warriors' plant wheat grass where yellow star thistle and leafy spurge once grew. Everyone agrees they'll never get rid of weeds in Hells Canyon. But by mixing new and old techniques they hope to restore at least some of the natural balance that once existed in this wild place.

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