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Open-File Report 2009-1113

Prepared in cooperation with Western Geographic Science Center, Menlo Park, California and University of Nevada, Reno, Nevada

Ecology of Greater Sage-Grouse in the Bi-State Planning Area Final Report, September 2007

By Michael L. Casazza, Cory T. Overton, Melissa A. Farinha, Alicia Torregrosa, Joseph P. Fleskes, Michael R. Miller, James S. Sedinger, and Eric Kolada

Thumbnail of and link to report PDF (1.37 MB)Executive Summary

Conservation efforts for greater sage-grouse (Centrocercus urophasianus), hereafter sage-grouse, are underway across the range of this species. Over 70 local working groups have been established and are implementing on-the-ground sage-grouse oriented conservation projects. Early on in this process, the California Department of Fish and Game (CDFG) recognized the need to join in these efforts and received funding from the U.S. Fish and Wildlife Service (USFWS) under the Candidate Species Conservation Program to help develop a species conservation plan for sage-grouse in the Mono County area. This conservation plan covers portions of Alpine, Mono, and Inyo counties in California and Douglas, Esmeralda, Lyon, and Mineral counties in Nevada. A concurrent effort underway through the Nevada Governor’s Sage-grouse Conservation Team established Local Area Working Groups across Nevada and eastern California. The Mono County populations of sage-grouse were encompassed by the Bi-State Local Planning Area, which was comprised of six population management units (PMUs). The state agencies from California (CDFG) and Nevada (Nevada Department of Wildlife; NDOW) responsible for the management of sage-grouse agreed to utilize the process that had begun with the Nevada Governor’s Team in order to develop local plans for conservation planning and implementation.

Resources from the USFWS were applied to several objectives in support of the development of the Bi-State Local Area Sage-grouse Conservation Plan through a grant to the U.S. Geological Survey (USGS). Objectives included: (1) participate in the development of the Bi-State Conservation Plan, (2) compile and synthesize existing sage-grouse data, (3) document seasonal movements of sage-grouse, (4) identify habitats critical to sage-grouse, (5) determine survival rates and identify causal factors of mortality, (6) determine nest success and brood success of sage-grouse, and (7) identify sage-grouse lek sites. Progress reports completed in 2004 and 2005 addressed each of the specific objectives and this final report focuses on the biological information gathered in support of local conservation efforts.

Participation in the development of the Bi-State Local Area Conservation Plan was accomplished on multiple scales. Beginning in the fall of 2002, USGS personnel began participating in meetings of local stakeholders involved in the development of a sage-grouse conservation plan for the Bi-State planning area. This included attendance at numerous local PMU group meetings and field trips as well as participating on the technical advisory committee (TAC) for the Bi-State group. Whenever appropriate, ongoing results and findings regarding sage-grouse ecology in the local area were incorporated into these working group meetings. In addition, the USGS partnered with CDFG to help reorganize one of the local PMU groups (South Mono) and edited that portion of the Bi-State plan. The USGS also worked closely with CDFG to draft a description of the state of knowledge for sage-grouse genetic information for inclusion in the Bi-State Conservation Plan. The first edition of the Bi-State Conservation Plan for Greater Sage-Grouse was completed in June 2004 (Bi-State Sage-grouse Conservation Team 2004).

This report is organized primarily by PMU to facilitate the incorporation of these research findings into the individual PMU plans that compose the Bi-State plan. Information presented in this report was derived from over 7,000 radio-telemetry locations obtained on 145 individual sage-grouse during a three year period (2003-2005). In addition, we collected detailed vegetation measurements at over 590 habitat sampling plots within the study area including canopy cover, shrubs, forbs, and grasses diversity. Vegetation data collection focused on sage-grouse nests, and brood-use areas. Additionally we collected data at random sites to examine sage-grouse habitat relationships within the study area. The majority of the fieldwork was conducted within Mono County, California, although many of the radio-marked birds moved freely between various state and county jurisdictional boundaries. We radio-marked birds in four of the six Bi-State PMUs (Desert Creek/Fales, Bodie Hills, South Mono, and White Mountains), and only in one area did radio-marked birds cross PMU boundaries. Birds marked in the Bodie Hills PMU were often found in the Mt. Grant PMU as the border between these two PMUs was decided primarily for jurisdictional reasons to facilitate planning efforts and was not entirely based on specific grouse populations. Based on initial findings obtained through radio-tracking, additional information regarding the interactions between sage-grouse in the Bodie Hills and the Mt. Grant PMU is warranted.

We provided all of the sage-grouse location and movement data in both hard copy and digital format to each PMU team in order to facilitate use of these data for future sage-grouse conservation planning and project implementation. Home range sizes for sage-grouse differed by capture site and sex, with the largest home ranges in Bodie Hills PMU and some of the smaller home ranges occurring in the Desert Creek/Fales PMU and the Parker Creek area within the South Mono PMU region. The size of home ranges of hens with broods was consistent across study areas and tended to be smaller than that of most males and hens without broods. Nest survival rates were consistent between years, averaging approximately 40% from 2003 to 2005, while the average annual reproductive success (i.e. probability of a hen hatching at least one egg) was 50%. Long Valley (34%) and Fales (44%) had the lowest annual reproductive success, while the Bodie Hills and Desert Creek areas were close to 60%. Clutch size was consistent, with an average of 6.5 eggs/nest.

Mortality events were intermittent during the study with the majority occurring throughout the breeding and summer/fall seasons. The direct cause of mortality was determined as accurately as possible. Avian, mammalian, and unknown predation types occurred in similar proportion; approximately 30% each. Approximately 4% of mortalities were attributed to West Nile Virus, all of which occurred in 2004 and 2005. Common avian predators on adult sage-grouse included great horned owls (Bubo virginianus) and golden eagles (Aquila chrysaetos), while common ravens (Corvus corax) were documented nest predators. Mammalian predators on adult grouse included coyotes (Canis latrans) and bobcats (Felis rufus), while badgers (Taxidea taxus) and coyotes were documented depredators of sage-grouse nests.

Shrub cover was greater at nest sites than at random sites close to the nest (50-200m). Sage height was also generally higher at nest sites than at nearby or random sites within the study area. Vegetation at nests in the Fales region of the Desert Creek/Fales PMU had the highest percent shrub canopy cover (56.8%).

Ownership and land management responsibilities for habitats utilized by grouse varied among PMUs. Grouse were found primarily on US Forest Service (USFS) lands in the Desert Creek/Fales and White Mountains PMUs, Bureau of Land Management (BLM) lands in the Bodie Hills PMU, and Los Angeles Department of Water and Power (LADWP) lands in the South Mono PMU. Private lands provided a significant proportion of the habitat use points in the Bodie Hills, Desert Creek/Fales, and to a lesser extent the South Mono PMU.

Sage-grouse conservation in the Bi-State area is dependant on the success of the local PMU groups. These groups rely on all of the participants involved in the local conservation efforts to provide the expertise, energy, and conservation ethic necessary to implement sound conservation practices for sage-grouse. All PMUs of the Bi-State plan share a common thread. They all recognize the need for sound scientific information on which the planning and implementation of conservation efforts for sage-grouse must be based. This report provides a baseline of information for conservation of sage-grouse in the Bi-State Planning Area.

For additional information contact:
Director, Western Ecological Research Center
3020 State University Drive East
Modoc Hall, Room 3006
Sacramento, CA 95819
http://www.werc.usgs.gov/

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Suggested citation:

Casazza, M.L., Overton, C.T., Farinha, M.A., Torregrosa, Alicia, Fleskes, J.P., Miller, M.R., Sedinger, J.S., and Kolada, Eric, 2009, Ecology of greater sage-grouse in the Bi-State Planning Area Final Report, September 2007: U.S. Geological Survey Open-File Report 2009-1113, 50 p.



Contents

Executive Summary

Acknowledgements

Conservation Planning

Field Studies

Desert Creek/Fales PMU

Bodie Hills PMU/Mt. Grant PMU

South Mono PMU

White Mountains PMU

References Cited


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