Noxious Weeds - A Growing Problem

By John Nelson - IDFG Sr. Wildlife Technician, Clearwater Region Every outdoor enthusiast has encountered noxious weeds on their outdoor excursions. Whether wading through Yellow Starthistle, hunting upland game or looking for grass for elk-packing stock and finding only knapweed, hunters know how annoying weeds can be. While annoying to us, weeds can ultimately be lethal to wildlife. Weeds can negatively change plant composition and vegetation communities, replacing important forage and cover species wildlife rely on. Literally hundreds of thousands of acres of big game winter range have been replaced with knapweed or starthistle in Idaho. This drastically reduces the availability of needed forage for deer and elk and reduces the number of big game these ranges can support. Many wildlife species also tend to avoid weed infestations, which may cause wildlife to use areas where they are more susceptible to predation and harvest. Through partnerships created by concerned private property owners, conservation organizations, and local, county, state, tribal, and federal government entities, Idaho is leading the way in fighting these invasive species. Millions of dollars are spent combating noxious weeds around the state annually. Through grants, cost sharing and other programs, managers are fighting to limit the spread of the invaders. The Idaho Department of Fish and Game (IDFG) also recognizes this increasing weed problem and expends significant effort and money annually to combat noxious weeds. On the Craig Mountain Wildlife Management Area south of Lewiston, new invaders like Whitetop, Hawkweed, Leafy Spurge, and Dalmatian Toadflax are treated with the highest priority goal of complete eradication. For established species such as Yellow Starthistle, Scotch Thistle and Knapweed, the goal is to stop the spread and contain the infestations. If they occur in an isolated patch, eradication is the goal. IDFG utilizes several management techniques used to fight weeds, including mechanical, chemical and biological control methods. Mechanical methods include mowing, burning, and hand pulling of weeds. Bio-control agents (insects) that target certain species of weeds have been released to control weeds such as yellow starthistle and Dalmatian toadflax. Other species are mechanically treated by pulling, chopping, or disking. However, chemical treatment is the most commonly utilized option where feasible. This year Idaho Department of Fish and Game received a grant from the Rocky Mountain Elk Foundation (RMEF) to control whitetop on Craig Mountain. Whitetop is currently expanding its range and spreading into important big game wintering areas. Without control measures, the once-healthy winter range becomes a monoculture with little or no wildlife value. This grant allowed Fish and Game to aerially treat 630 acres of whitetop in early May. It would have taken approximately five months to treat this acreage from the ground which is impractical due to the limited time when chemical treatment of this species is effective and the ruggedness of the terrain. While noxious weeds may seem to be an insurmountable problem, all outdoor enthusiasts and good neighbors can help stop the spread of weeds by following the suggestions below: Be weed savvy and recognize that there is a problem. Learn to identify weed species and report new weed locations to your local county weed superintendent, Forest Service, Bureau of Land Management or IDFG. Be good neighbors. Control weeds on your land and assist others on theirs. Clean your equipment. When entering public and private land check to make sure your vehicles, animals and gear are free of weed seeds. Use weed free hay and feeds for your livestock. Tread lightly. Try to minimize any ground disturbance by staying on established travel routes and use low impact camping techniques. With cooperative efforts between everyone, we can make a difference. The worst thing to do is to do nothing. We may not be able to eradicate all weeds, but we can reach a level where the problem is manageable and both people and wildlife can live with it.