F LO R A A N D FA U N A
Avoiding
noxious weeds BY JOHN COUNCILMAN
Invasive non-native plants, animals and diseases are getting more press and for good reason. Native ecosystems and all that depend on them are at risk. The Center for Invasive Species Management reports invasive species are the second leading cause of animal population decline and extinction worldwide. Once invasive species get established, nature has no mechanisms that enable landscapes to restore ecological balance. It’s difficult to raise awareness about this issue. Weeds aren’t a glitzy endangered species that get a lot of press. However, fighting weeds protects the habitat these species live on. Noxious weeds are plants designated as injurious to agricultural or horticultural crops, natural habitats or ecosystems, humans or livestock. There are hundreds of noxious weeds in North America, with 32 listed in Montana. Consider the example of spotted knapweed. Once the invasive is established along a river, seeds float downstream, infesting gravel bars and river banks. This increases soil erosion and negatively affects fish habitat. Research shows runoff increases by 150 percent and sediment yields by 300 percent in areas of invasive spotted knapweed. Other wildlife is also affected. Spotted knapweed can reduce winter forage for elk by 50 to 90 percent. This can change
62 Explore Yellowstone explorebigsky.com
seasonal elk distribution patterns. Habitat decline is also a primary threat to local bighorn sheep populations. Noxious weeds come from all around the world and often invade disturbed areas like roadsides, powerline clearings, trails, construction sites and burned or logged areas. However, because they are so competitive, they can get established almost anywhere. And unlike native plants, they usually have no natural control like bugs that eat them or diseases that keep their populations in check. Weeds spread easily via cars, ATVs, motorcycles, dogs, heavy equipment, livestock, hay, contaminated topsoil or gravel, hiking boots, clothing, fishing waders, and more. Getting educated, though, is key for prevention. Learn to identify invasive plants and other weeds by visiting gallatinisa.org. You can also download “Montana’s Noxious Weeds” from the Montana State University Extension by visiting store.msuextension.org. John Councilman is a retiree from the U.S. Forest Service with over 40 years of experience working in the Northern Rocky Mountains on a wide variety of vegetation and wildlife management issues. He is currently the board chair of the Gallatin Invasive Species Alliance.
