Columbian Sharp-Tailed Grouse (Tympanuchus Phasianellus Columbianus): a Technical Conservation Assessment
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Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus): A Technical Conservation Assessment Prepared for the USDA Forest Service, Rocky Mountain Region, Species Conservation Project August 17, 2007 Richard W. Hoffman1 and Allan E. Thomas2 11804 Wallenberg Drive, Fort Collins, Colorado 80526 25001 Decatur Drive, Boise, Idaho 83704 Peer Review Administered by Society for Conservation Biology Hoffman, R.W. and A.E. Thomas. (2007, August 17). Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus): a technical conservation assessment. [Online]. USDA Forest Service, Rocky Mountain Region. Available: http://www.fs.fed.us/r2/projects/scp/assessments/columbiansharptailedgrouse.pdf [date of access]. ACKNOWLEDGEMENTS The authors thank K.J. Eichhoff and H.E. Vermillion of the Colorado Division of Wildlife for their assistance in preparing the figures and C.E. Soldati, a student at Colorado State University, for her help in preparing the References section. J.A. Boss, librarian for the Colorado Division of Wildlife, was extremely helpful in locating and obtaining many of the references used to prepare this assessment. T.P. Woolley, biologist with the Wyoming Game and Fish Department, provided lek survey data and answered many questions regarding the distribution and management of Columbian sharp-tailed grouse in Wyoming. This assessment also benefited from information provided by A.D. Apa, M.A. Schroeder, and A.W. Spaulding. D.P. McDonald of the University of Wyoming conducted the lifecycle model analyses and prepared the summary of the results. C.E. Braun and an anonymous reviewer provided constructive comments that substantially improved the quality of the assessment. Finally, the authors are extremely grateful to G.D. Patton and P.M. McDonald with the USDA Forest Service, Rocky Mountain Region. Their support, technical guidance, understanding, and most of all, patience, made the preparation of this assessment easier. AUTHORS’ BIOGRAPHIES Richard W. Hoffman earned his B.Sc. and M.Sc. Degrees in wildlife biology from Colorado State University. He subsequently worked for the Colorado Division of Wildlife for over 30 years as an avian researcher specializing in upland game birds. He has conducted research on population dynamics, habitat relationships, nutritional ecology, and behavior of white-tailed ptarmigan, dusky grouse, greater prairie-chickens, Columbian sharp-tailed grouse, and wild turkey. In retirement, he continues to work on projects involving white-tailed ptarmigan, greater sage-grouse, and Columbian sharp-tailed grouse. Allan E. Thomas earned his B.Sc. Degree in wildlife management with minors in fisheries and range management from the University of Arizona. He also conducted graduate work at the same university and received additional credits from attending schools in Washington, South Dakota, Arkansas, Alaska, and Idaho. His work experience spans more than 50 years and includes positions primarily with the Bureau of Land Management (22 years) and U.S. Fish and Wildlife Service (19 years). He retired from the Bureau of Land Management in 1999 and started another career as a private consultant in Boise, Idaho. DEDICATION Sadly, Allan E. Thomas passed away before this assessment was completed. Allan was a devoted conservation biologist who believed strongly in documenting and communicating biological information. This assessment is testimony to Allan’s work ethic and is dedicated to his memory. COVER PHOTO CREDIT Photograph of male Columbian sharp-tailed grouse in an alert posture by Richard W. Hoffman. 2 3 SUMMARY OF KEY COMPONENTS FOR CONSERVATION OF COLUMBIAN SHARP-TAILED GROUSE Status The Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus; CSTG) is one of six existing subspecies of sharp-tailed grouse in North America. It is endemic to big sagebrush (Artemisia tridentata), shrubsteppe, mountain shrub, and riparian shrub plant communities of western North America. The subspecies currently occupies less than 10 percent of its historic range, with only three metapopulations remaining in central British Columbia, southeastern Idaho and northern Utah, and northwestern Colorado and south-central Wyoming. Within Region 2 of the USDA Forest Service (USFS), this grouse formerly occurred in as many as 22 counties in western Colorado and in portions of 11 counties in west-central, southwestern, and south-central Wyoming. Today, viable populations occur in only three counties in Colorado and one county in Wyoming. Attempts are being made to reintroduce CSTG to previously occupied habitats in southwestern and north-central Colorado. Approximately 68 percent of the occupied habitat in Region 2 is on private lands, and only 4 percent is on lands administered by the USFS. The CSTG has been petitioned twice for listing under the Endangered Species Act. Under both petitions, the finding was not warranted. USFS Region 2 and the state offices of the Bureau of Land Management in Colorado and Wyoming have designated the CSTG a sensitive species. Both the Wyoming Game and Fish Department and Colorado Division of Wildlife list it as a species of special concern. Primary Threats Threats to CSTG are widespread across its range in Region 2, occur at all spatial scales, and transcend local, state, and regional jurisdictions. Many of the threats are inter-related and synergistic in their impacts on CSTG. Even when the threats are not related, their impacts tend to be cumulative. The primary threats are all human-related. Foremost are habitat loss and degradation caused by conversion of native habitats to pasture and croplands, overgrazing by domestic livestock, energy development, use of herbicides to control big sagebrush, alteration of natural fire regimes, invasion of exotic plants, and urban and rural expansion. Possible loss of Conservation Reserve Program (CRP) lands is the single most important immediate threat to CSTG in Region 2 and elsewhere throughout the subspecies’ range. Currently, CRP lands support 21 percent of the known active leks in Region 2, and many CRP fields provide critical nesting and brood-rearing habitats for CSTG. Nearly 70 percent of all CRP contracts within the occupied range of CSTG in Region 2 are scheduled to expire by 2010, and there are strong indications that Congress will not include provisions in the 2007 Farm Bill for their renewal. What will become of these lands if the contracts are allowed to expire is uncertain, but it is likely that their value as habitat for CSTG will diminish. Livestock grazing is the dominant use on public and private lands within the occupied range of CSTG in Region 2. While grazing levels have declined in Region 2, grazing continues to be an issue because lands subjected to past overgrazing have not been rested and given the opportunity to recover. Until recently, oil and gas development was not considered a threat to CSTG in Region 2. However, with oil and gas prices reaching all-time highs and with strong support from the current political administration, oil and gas exploration and development have increased dramatically throughout the West. This activity has expanded into the core range of CSTG in Region 2. Impacts of oil and gas development include direct habitat loss and fragmentation from well, road, and pipeline construction; displacement (i.e., avoidance behavior) of individuals caused by excessive human activity; increased avian predation due to the construction of artificial perch sites; and increased mortality due to collisions with utility lines and vehicles. If oil and gas resources in Region 2 are developed to their fullest potential, the outcome could be devastating to CSTG populations. The most essential component of habitats used by CSTG during winter in Region 2 is the presence of serviceberry (Amelanchier spp.). Serviceberry is the primary food source for CSTG from late fall through early spring. Any activity that reduces the distribution and abundance of serviceberry may have negative consequences to CSTG. 2 3 Primary Conservation Elements, Management Implications and Considerations The keys to successful management of CSTG in Region 2 are protection and enhancement of existing habitats and restoration of habitats that are no longer occupied or are severely degraded. The natural processes that perpetuate the habitats upon which CSTG rely have been significantly disrupted by human activities and are no longer intact. Consequently, in most situations, some form of human intervention is necessary to correct the problems. This may be as simple as eliminating the activity causing the problem and allowing the plant community to recover on its own, or it may involve extensive restoration of the plant community. Protection and management of native cover types should receive top priority. There should be no net loss of sagebrush, shrubsteppe, or mountain shrub cover types in Region 2. Some of the same activities responsible for the loss and degradation of shrubsteppe and mountain shrub habitats also may be used to enhance and restore these habitats when properly applied. These activities include prescribed fire, grazing, use of herbicides, and mechanical treatments. Managers must be acutely aware that multiple factors affect CSTG populations, and they should consider the cumulative effects of these factors when formulating any future management actions. 4 5 TABLE OF CONTENTS ACKNOWLEDGEMENTS............................................................................................................................................2