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Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 9/21/2012 Publication Date: 1/10/2013 Citation: Clements, C.D., Harmon, D.N., Blank, R.R. 2013. Rehabilitation of cheatgrass infested rangelands: an integrated approach [abstract]. Society for Range Management. 12:5. Interpretive Summary: Technical Abstract: Cheatgrass (Bromus tectorum) invasion has astronomically altered native plant communities throughout the Intermountain West. 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. Ray Evans pointed out more than three decades ago that as little as 4 cheatgrass plants per square foot can outcompete native and introduced perennial grass seedlings. It is not uncommon to have more than 100 cheatgrass plants per square foot throughout the Intermountain West. Rehabilitation of cheatgrass infested rangelands is a daunting task that faces resource managers annually. 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. 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. If you miss seeding the 1st fall following a big sagebrush wildfire, the window drastically closes and any success is very limited and the need for a more innovative and expensive treatment is needed. Mechanical and herbicide treatments are also tools that can be used in decreasing cheatgrass seed bank densities. The disc and fallow method decreased cheatgrass from 148/ft² down to 17/ft², 89% reduction, therefor decreasing the competition that cheatgrass poses to seeded species in the seedling year. Herbicides such as Plateau and Landmark also did an excellent job of controlling cheatgrass. Landmark applied at 1.75 oz.ac rate in the fall of 2010 and then seeded to perennial grasses in the fall of 2011 after a one-year fallow significantly decreased cheatgrass above-ground densities from 79.6/ft² down to 0.8/ft², 99% control. Perennial grass seedlings averaged 16.8/ft² the first growing season with many of the seedlings producing seed their first year. An integrated approach without limiting the tools available to resource managers does show promise when attempting the rehabilitation of cheatgrass infested rangelands. |
