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United States Department of Agriculture

Agricultural Research Service

Research Project: Invasive Species Assessment and Control to Enhance Sustainability of Great Basin Rangelands

Location: Great Basin Rangelands Research

Title: Rehabilitation of Cheatgrass-Infested Rangelands: Management

Authors
item Clements, Darin
item Young, James
item Harmon, Daniel
item Blank, Robert

Submitted to: The Progressive Rancher
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 4, 2013
Publication Date: January 7, 2014
Citation: Clements, C.D., Young, J.A., Harmon, D.N., Blank, R.R. 2014. Rehabilitation of Cheatgrass-infested rangelands: management. The Progressive Rancher. 14(1):28-29.

Interpretive Summary: This is the final part of a three part series specifically addressing lessons learned concerning the management of rehabilitated cheatgrass-infested rangelands. In our first series we pointed out some of the competitive advantages cheatgrass possesses to be successful on Great Basin rangelands. Adding to those advantages, the ability of cheatgrass to outcross with neighboring cheatgrass plants or other Bromus species has been an area of contention by many. G. Ledyard Stebbins, a former professor of genetics at the University of California at Davis pointed out as early as 1957, "... genetic variability must be very slow, unless the number of individuals is enormously large and reproduction is very rapid ... a few generations of outcrossing can give rise to hundreds or even thousands of new genotypes." Dr. Stebbins did not specifically mention cheatgrass, but the description sure fits. In 2008, P. M. Fortune and others reported that an Eastern Mediterranean grass, Bromus fasciculatus and Bromus tectorum (cheatgrass) were the parents of Bromus rubens (red brome), which is an enormous problem in the southern Great Basin. The ability of cheatgrass to improve itself genetically through self-fertilization and outcrossing behavior is cause of great concern as cheatgrass moves into habitats formerly thought to be resilient to such invasions. Another area of contention is the use of introduced plant materials on Great Basin rangelands. Some environmental and ecologically focused groups demand that native species should only be used in restoration/rehabilitation efforts. In 1999, following the firestorms that consumed 1.8 million acres in Nevada alone, 1.4 million pounds of native seed and 3.4 million pounds of seed of introduced species was purchased by the USDI, Bureau of Land Management and seeded by aerial broadcast and drill seeding methodologies. These seedings resulted in near complete failures. If it was very risky to seed such species as bluebunch wheatgrass in the 1940’s before cheatgrass became such a dominant species on Great Basin rangelands, what are the chances of widespread range restoration using native species today? Another critical topic in the management of Great Basin rangelands falls under stewardship. Without good stewardship, degradation of Great Basin rangelands will occur. Good stewardship reduces conflict in many cases, poor stewardship on the other hand will lead to numerous conflicts. The management of Great Basin rangelands must be active, not passive. With so many acres already converted to cheatgrass-dominance, managers are very nervous to apply any range improvement practices in fear of failing and promoting further conversions. A plant community is the result of past disturbances or lack of disturbances. If you lose the long-lived perennial grasses to improper grazing or let the site be takeover by big sagebrush, the site will eventually burn and the active cheatgrass seed bank will occupy the vacuum. If you actively manage the site to maintain the presence of long-lived perennial grasses, then active suppression of cheatgrass can take place. Along with the active on-the-ground management of Great Basin rangelands come the additional concerns with Policies. Whether it’s the bureaucratic constraints of purchasing desired wildland seed for rehabilitation/restoration practices, native seed only policies, or the policy of resting a site for two years following a wildfire, these policies can promote failure. We argue these policies should be guidelines and be more flexible with on-the-ground realities. The Rehabilitation of Cheatgrass-Infested Rangelands is a very demanding task that requires the understanding of the competitive nature of cheatgrass, rehabilitation/restoration practices that provide the best opportunity to be successful and reduce the threat of cheatgrass as well as account

Technical Abstract: This is the final part of a three part series specifically addressing lessons learned concerning the management of rehabilitated cheatgrass-infested rangelands. Steve Novak and Richard Mack reported in 2003 that they found no evidence of outcrossing in 2,000 cheatgrass seedlings from 60 North American populations. At the same time we proposed that cheatgrass was expressing hybrid vigor as we witnessed exerted anthers in the field. Mike Ashley and Bill Longland of the USDA-Agricultural Research Service, Great Basin Rangelands Research Unit reported in 2007 evidence of such outcrossing in western Nevada. In 2008, P. M. Fortune and others reported that an Eastern Mediterranean grass, Bromus fasciculatus and Bromus tectorum (cheatgrass) were the parents of Bromus rubens (red brome), which is an enormous problem in the southern Great Basin. The ability of cheatgrass to improve itself genetically through self-fertilization and outcrossing behavior is cause of great concern as cheatgrass moves into habitats formerly thought to be resilient to such invasions. K. R. Merrill and others reported in 2012 that the outcrossing of cheatgrass was really of no consequence since they had measured it at only 0.58% occurrence. For example, we measured 173 cheatgrass plants/ft² in May 2001 following a 1999 wildfire event, if only 0.58% of those plants outcross there are at least 54,000 individual cheatgrass plants/acre exhibiting this outcrossing ability, this is alarming. Another area of contention is the use of introduced plant materials on Great Basin rangelands. Some environmental and ecologically focused groups demand that native species should only be used in restoration/rehabilitation efforts. In 1999, following the firestorms that consumed 1.8 million acres in Nevada alone, 1.4 million pounds of native seed and 3.4 million pounds of seed of introduced species was purchased by the USDI, Bureau of Land Management and seeded by aerial broadcast and drill seeding methodologies. These seedings resulted in near complete failures. If double or triple the amount of native seed had been seeded to these burnt rangelands would we have experienced twice or three times the success? We don’t believe so. If it was very risky to seed such species as bluebunch wheatgrass in the 1940’s before cheatgrass became such a dominant species on Great Basin rangelands, what are the chances of widespread range restoration using native species today? As we have pointed out in the previous two series of this topic, the best known method at suppressing cheatgrass is through the establishment of long-lived perennial grasses. If your goal is truly to suppress cheatgrass, decrease the frequency of wildfires, and allow succession to take place; then, the establishment of long-lived perennial grasses is essential. The replacement of cheatgrass with perennial plants has been a management and research priority for more than eighty years. It is important to understand that the perennial grass species you are trying to establish has to have the ability to germinate, emerge, compete and establish in that specific environment under the face of such competitive species as cheatgrass. In 2006, a wildfire swept through part of the Rodeo Creek Allotment in northwestern Nevada killing the Wyoming big sagebrush shrubs and opening the window for the transition to cheatgrass dominance. We set up a study site within the burned area to test a number of plant materials and methodologies in an effort to reduce the cheatgrass dominance following this wildfire. In 2008-2009 we reported on the establishment of perennial grass (crested wheatgrass) at 9.3 perennial grass/m², which successfully suppressed cheatgrass by reducing the above-ground cheatgrass densities by 95%. The permit to this allotment changed hands in 2010 and poor stewardship followed. The combination of the extremely dry year of 2011-2012 and improper grazing management resulted in a 93% loss of perennial grasses (crested wheatgrass) and a 630% increase in cheatgrass. The transition of this site to cheatgrass dominance occurred in a very short two years. Unfortunately, cheatgrass-dominance will last for many decades without an innovative and extremely expensive cheatgrass control program and seeding effort. Not only has this poor stewardship caused future management problems for this allotment and permitee, it also reflects poorly on its’ neighbors, the Cattlemen’s Association and the Livestock Industry as a whole. Along with the active on-the-ground management of Great Basin rangelands come the additional concerns with Policies. Whether it’s the bureaucratic constraints of purchasing desired wildland seed for rehabilitation/restoration practices, native seed only policies, or the policy of resting a site for two years following a wildfire, these policies can promote failure. We argue these policies should be guidelines and be more flexible with on-the-ground realities. For example, in 1999, the wildfire that burned from Lovelock to Winnemucca, Nevada crossed many allotments and were closed off to grazing under policy for two years. By May of 2001, it was obvious that rehabilitation/restoration efforts were a dismal failure as cheatgrass densities were 173/ft² and posed a serious wildfire threat. Resource and land managers on-the-ground realized that the site was not going to magically restore itself just because livestock had been removed, yet the policy handcuffed them to be able to perform fuels management. The USDI, Fish and Wildlife Service has an histogram that reflects that the top two threats to sage grouse habitat in the West are Invasive Species and Wildfire. Let’s be honest, in cheatgrass-infested rangelands these two could be considered one in the same. Why then would you have a policy in place that promotes cheatgrass and the associated wildfire threats? The Rehabilitation of Cheatgrass-Infested Rangelands is a very demanding task that requires the understanding of the competitive nature of cheatgrass, rehabilitation/restoration practices that provide the best opportunity to be successful and reduce the threat of cheatgrass as well as accountability at various levels in the management decisions that impact these rangelands. Our goal is simply to provide resource and land managers with the necessary information required to best combat the advancement of cheatgrass through an integrated weed control program and rehabilitation practices that will suppress cheatgrass densities, fuel loads, and allow succession to take place to improve wildlife and grazing resources.

Last Modified: 7/23/2014
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