Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2012
Publication Date: 12/6/2012
Citation: Clements, D.D., Harmon, D.N., Blank, R.R. 2012. Cheatgrass invasion and wildlife habitat [abstract]. Nevada Wildlife Commission.
Technical Abstract: The introduction and subsequent invasion of cheatgrass (Bromus tectorum) has altered native plant communities and the wildlife species that depend on these communities. Cheatgrass has truncated secondary succession by outcompeting native plant species for limited resources, thus building persistent seed banks to take advantage of conditions that occur in arid environments. The presence of cheatgrass has increased the chance, rate, spread and season of wildfires. With each passing wildfire season, more and more critical islands of wildlife habitat are lost to cheatgrass fueled wildfires. Wildlife species that depend on sagebrush (Artemisia sps.) and other browse species to be healthy and productive such as sage grouse (Centrocercus urophasianus) and mule deer (Odocoileus hemoinus) are especially troubled by these cheatgrass fueled wildfires. Sage grouse are a candidate species to be listed on the Threatened and Endangered Species List and mule deer are the only declining big game species in North America. The establishment of long-lived perennial grasses is the key at suppressing cheatgrass densities and fuel loads. The use of natural and prescribed fires in big sagebrush (Artemisia tridentata) communities can open a window for successful rehabilitation efforts as these fires burn hot enough for a long enough period of time to kill the majority of cheatgrass in the seed bank. On the other hand, a wildfire in a cheatgrass dominated community burns so fast that live seeds are numerous in the seed bank as well as on the soil surface. The decrease in available nitrogen also limits cheatgrass germination the 1st fall and spring following the wildfire, therefor decreasing the competition that desirable seeded species will face the following spring. Seeded species such as crested wheatgrass (Agropyron cristatum), ‘Immigrant’ forage kochia (Bassia prostrata), and Sherman big bluegrass (Poa ampla) experienced significantly more seedling success when seeded the 1st fall following the wildfire than when seeded the 2nd fall following the wildfire. These species also significantly decreased cheatgrass above-ground densities, i.e. 25 cheatgrass/ft² reduced to 4 cheatgrass/ft² in the crested plots. The ability of plant materials used in restoration/rehabilitation practices of western rangelands is critical if successful efforts are to be yielded. The species used must have the inherent potential to germinate, emerge and compete in these arid environments in the face of such weed competitors as cheatgrass. Mechanical and herbicide treatments are also tools that can be used in decreasing cheatgrass seed bank densities. An integrated approach to rehabilitation of degraded rangelands is critical if we are to improve rehabilitation practices to benefit wildlife.