The Federal Bureau of Investigation made a science of learning to meld forensic evidence, personality factors, and other elements into profiles of uncaught criminals. UI weed scientist Tim Prather and his students are using what the landscape can tell us to help predict and control new outbreaks of noxious weeds in Idaho.

Taking the law enforcement metaphor even further, Prather, with support from the Idaho State Department of Agriculture, county weed superintendents, and land management agencies, has fielded a SWAT team the past two summers. The Special Weapons and Tactics team employs everything from global positioning system (GPS) receivers to geographic information systems (GIS) databases to assess weed threats and eliminate them when possible.

Long associated with agriculture, and specifically fields and range, weeds now infest even the state’s least developed areas. Weeds pose a serious threat to Idaho’s environmental and economic well being. U.S. Forest Service Chief Dale Bosworth mused that the explosion of noxious weeds in Idaho and elsewhere will prove to be one of the 192-million-acre national forest system’s greatest environmental problems in the 21st Century. There are ways that land managers and weed control superintendents can get a leg up on weed control efforts by focusing on areas where weeds are beginning to take root or are likely to in the near future, Prather said. Profiling the landscape offers the best hope for future missions to detect new weed invasions before they spread, the University of Idaho researcher noted.

The profile would take into account the lay of the land and its existing vegetation. The information would help landowners and managers decide where to look for invasive weeds such as yellow starthistle. Prather is overseeing a pilot study by UI graduate student Brett Bingham to learn the competitive limits of yellow starthistle that in turn limit where the plant grows. This weed ranks among Idaho’s 10 worst in terms of acreage and economic damage. It also threatens wildlife by replacing forage. Bingham has established experiments along the Clearwater and Snake River breaks to study how starthistle responds to competition.

Knowing how much vegetation grows in an area can help predict whether existing plants can prevent starthistle from invading. The pilot project on competition, and another planned to look at the physiological limits on starthistle’s growth, will paint a picture of where the noxious weed might grow in the future. The second project, by graduate student Lee Eubank, will test how factors such as soil depth, the steepness of the slope, and the direction it faces affect starthistle growth. Properties of the soil can fill in more details to show the weed’s physiological limits.

Prather said the intent is to keep the big picture in view. “If we find general factors that limit yellow starthistle’s distribution, then we should be able to go to a new area and say, ‘Here’s the competitive limit and here’s the physiological limit. Anything within those limits might be susceptible to invasion.’ ”

Focusing on specific areas that are vulnerable will help make management planning efforts more efficient. The research is funded through the USDA Agricultural Research Service.

Hells Canyon, where Idaho, Oregon and Washington borders meet, is likely to be one of the first places where an Idaho-specific system will be used. Starthistle is creeping south into the canyon, one of the deepest in North America, threatening its native plants and wildlife. The system predicts the slopes and aspects most likely to contain yellow starthistle.

The Nature Conservancy, which operates the Garden Creek Preserve near the canyon’s northern end, may begin using the information this year to guide efforts to detect new patches of the weed, Prather said. “County weed superintendents in southern Idaho have arrested its progress. They’re seeing fewer plants every year so I would say their efforts have paid off,” Prather said. “The counties are very aware of yellow starthistle’s potential so they’re paying close attention.” The UI research will help them decide where to look next and keep them from being blindsided, Prather said.

That’s the mission of the weed SWAT team as well. In addition to the palm-sized computers, GIS and GPS to find and track weed infestations, Prather’s team uses vehicles ranging from kayaks to jet boats and fourwheelers to four-wheel-drive pickups to investigate weed reports. The team works closely with county, state and federal officials and through cooperative weed management areas. Their job is to seek out and survey infestations so they can be destroyed.

The team spent last summer and this summer investigating reports of weed discoveries and helping with plans to turn back weedy tides elsewhere. In mid- August, the team worked with Latah County to track tansy ragwort, which can poison cattle and horses.

Earlier, Eubank, Borek and fellow team members Jon Yates and Daniel Hailey, all UI students, rode a jet boat up the wild Salmon River and into the sprawling Frank Church–River of No Return Wilderness. The team searched for pockets of dyer’s woad, a plant that has shown explosive growth in some parts of southern Idaho.

The team operates seasonally and works closely with plant taxonomist Sandra Robins, who runs the Lambert Erickson Weed Diagnostic Laboratory at UI. Her job is to identify and research plants that pose a threat to the state.

After the wilderness trip, the team headed for suburban Post Falls to investigate a record from the lab’s files. The eight-year-old report detailed the discovery of a Himalayan plant, policeman’s helmet or poor man’s orchid, with the potential to be a major problem if it spread.

An infestation of Japanese knotweed along the Lochsa River led the team to kayak the famous whitewater river to locate populations along the riverbank. “It’s not a bad job for the summer,” Prather said. Still, one search for yellow starthistle on a 105-degree day did give the crew a benchmark for comparing the difficulty of all future jobs.

The crew’s funding comes through the Idaho State Department of Agriculture as part of the federal-statecounty partnership that operates Cooperative Weed Management Areas.

Most of the UI team’s efforts are directed by the priorities set by cooperative weed management area team members, who are generally county weed superintendents. The main thrust is to respond quickly to new weed sightings, map the plants’ extent, then eradicate them.

The team helps to assemble a map to guide weed control efforts, then revisits the sites to determine their success.