DIE-OFF CASE STUDIES

Case Study Analysis Methodology

INTRODUCTION
This examination of detailed bighorn die-off case studies was conducted for a Master's thesis written by me (Tristan Howard) from 2011-2013 while pursuing an MS in Geography at the University of Montana in Missoula. The full thesis can be found as PDF here, but the case study pages accessible via the menu bar at left lay out its key findings in a quicker-to-navigate online format. The thesis examines bighorn-domestic sheep interaction policy efficacy by providing investigations and comparisons of six bighorn disease outbreaks that occurred in the western U.S. between 1990 and 2010.

I employed mixed methods, including case studies and policy analysis relying on extensive secondary research. Once case study locations and policy analysis criteria were decided, answers were sought via literature, semi-structured interviews, and questionnaires. Final results were analyzed with tables and comparisons.

SCOPE NARROWING AND THE CASE STUDY APPROACH
Numerous bighorn die-offs happened in the western U.S. from 1990 to 2010. See the die-off tables accesssible via the menu bar at left for numerous examples. To gain orientation on just what happened and what could be feasibly researched, listings of major bighorn disease outbreaks by state were compiled. Sources for such listings and other background information include: proceedings of the Northern Wild Sheep and Goat Council and Desert Bighorn Council’s (DBC) meetings, state bighorn management plans, scientific journals, news articles, federal government documents, and Western Association of Fish and Wildlife Agency (WAFWA) reports.

Compiling and analyzing lists of disease incidents helped with settling on a case study approach focusing on six discrete die-off cases or events. This approach yielded a cross-sectional representation of wild-domestic sheep policies across the western U.S. Such representation was a research goal because it seemed a suitable avenue for compiling useful results in an achievable manner. The multiple case study approach allowed in-depth analysis of particular events and their situations in particular locations. Such an approach also produced results that can be generalized for speculation on trends in broader regions. Examining one event would produce results with too narrow of a scope for this project’s aims, and even a cursory analysis of all discovered 1990-2010 disease outbreaks would not be practical because of limits on time and information availability. Thus, a case study methodology focusing on six events was deemed an effective and feasible way to approach this project’s questions. Additionally, such an approach allows for easy organization of data in forms suitable for comparisons and analysis.

Moreover, the case study approach fit well with the habitat use patterns of wild sheep. Bighorns often live in isolated populations in specific areas (e.g., individual mountain ranges, canyons, rims, etc.). They also tend to stick to one general area their entire lives (Toweill and Geist 1999). Thus, the case study approach fit well with the behavior of bighorns, and any areas examined were sure to have continuously hosted wild sheep for a significant amount of time before a disease outbreak.

Once context was acquired on just where and when most bighorn disease outbreaks occurred, this project’s geographic-temporal scope was narrowed with the aim of presenting a roughly cross-sectional representation intended to yield diverse, useful results. The timeframe of 1990-2010 was chosen for several reasons. The major Bureau of Land Management (BLM) policies for bighorn-domestic sheep interaction management (compiled by the DBC) were first presented in 1990 (DBC Technical Staff 1990). Furthermore, because the disease threat was not widely recognized until about the late 1980s (Brigham, Rominger, and Espinosa T. 2007; Hurley et al. 1999), 1990 is a fitting starting point for examining policy. By 1990, many managers should have had at least a fair idea of what various disease risks were in their respective locations and what could be done to reduce them.

With an upper bound of 2010, the scope of the topical and dynamic subject of bighorn disease is limited to ensure feasibility. Notable die-offs and news articles have continued beyond 2010, but keeping up with them and incrementally incorporating them into this project would have proved challenging. The capping date of 2010 was also chosen because updated recommendations from WAFWA for domestic sheep management in bighorn habitat were released in 2010, and they reflect how policy has evolved since 1990 and what should now be known (WAFWA 2010a). Additionally, the winter of 2009-2010 marked one of the most infamous in documented history for bighorn pneumonia outbreaks. About 890 bighorns (from nine populations in five states) died: a grim but relevant timeframe finale (WAFWA 2010b). One area (Bonner/West Riverside) that was part of this cluster of die-offs was chosen as a case study location.

With a methodology and timeframe established, the geographic scope of the research was narrowed via the selection of case study locations. Colorado, Montana, Nevada, and Oregon were chosen as states on which to focus. These states represent a large sampling of bighorn habitat and collectively host all subspecies that suffered disease outbreaks from 1990-2010. These states also experienced enough documented outbreaks to provide sufficient material for case studies, and they each have a bighorn management plan (CDOW 2009; MFWP 2010; NDOW 2001; ODFW 2003).

Case studies of specific 1990-2010 disease outbreaks and locations are the main foci of this project. However, as this study's background sections (accessible via the bighorn and disease problem background options in the menu bar at the upper left) illustrate, the scope for the overall investigation includes the entire western U.S. from primarily the mid-1800s to 2013. The bighorn-domestic sheep disease issue covers vast stretches of time and space.

RATIONALE FOR CASE STUDY CHOICES
The six case study locations were selected based on: information availability; presence of domestic sheep; and temporal, geographic, and subspecies representation. All locations hosted reasonably well-documented die-offs and nearby domestic sheep. Collectively, in general, locations are also chronologically, spatially, and taxonomically representative of bighorn die-offs across the West.

Data availability was an important factor in choosing locations. Regions with more outbreak data available were more likely to be chosen. Information on bighorn disease outbreaks is often incomplete, and the role of domestic sheep can be implied, unclear, or nonexistent. Some 1990-2010 outbreaks were attributed to domestic goats (Cassirer et al. 1996; Jansen et al. 2007). For this project, only locations with nearby domestic sheep were chosen. By focusing on areas with domestic sheep, a consistent series of analysis criteria are generally applicable to almost every location.

Locations were also chosen with a goal of temporal representation such that they reflect the middle, upper, and lower portions of the 1990-2010 timeframe. Chosen outbreak occurrence years include: 1991, 1994-1995, 1997-2000, 2007, and 2010. This temporal sampling reveals insights on policy evolution. Subspecies representation was another goal. The breakdown of subspecies per disease outbreak location is: three Rocky Mountain bighorn locations (two in Montana and one in Colorado), two California bighorn locations (Nevada and Oregon), and one desert bighorn location (Nevada). Rocky Mountain bighorns, Nevada, and Montana are disproportionately represented because that subspecies and those states experienced especially high numbers of outbreaks from 1990-2010.

CASE STUDY LOCATIONS
Google Earth was used to perform a cursory analysis of each location’s position. Every case study location is featured in the map below. These analyses provided general context on the biophysical and cultural attributes for each region. Such context was useful for later research. Additionally, the analyses made clear where case study locations were located relative to each other. This information verified the geographically broad and representative nature of the case study areas.

For Nevada, the Tobin range (respiratory bacterial infection of desert bighorns begun in 1991) and Hays Canyon Range (2007 pneumonia outbreak in California bighorns) were chosen (Arthur et al. 1999; Cummings and Stevenson 1995; NDOW 2008). For Montana, the Highland/Pioneer Mountains (1994-1995 pneumonia outbreak) and Bonner/West Riverside (2010 pneumonia outbreak) were chosen (Arthur et al. 1999; Aune et al. 1998; WAFWA 2010b). The Highland/Pioneer Mountains were chosen partly because their bighorns lived near domestic sheep for about 20 years with no serious disease issues (Aune et al. 1998). That coexistence factor offered potential for especially insightful findings on interaction management. Bonner/West Riverside was chosen because its bighorns live near mixed-use human development, which adds a unique dimension to management issues (WAFWA 2010a). For Colorado, the Tarryall/Kenosha Mountains (1997-2000 pneumonia outbreak) were chosen, and for Oregon, Aldrich Mountain (1991 pneumonia outbreak) was chosen (George et al. 2008; ODFW 2003).

west-wide map of bighorn die-off locations

COMPILING RESULTS
 For each case study location, profiles were compiled that include examinations of the following categories.

For examining biophysical geography, each location’s position, general topography, and vegetation are described. For land ownership, major land owners/managers of bighorn habitat are listed and discussed with occasional emphasis (when available data permits) on how much bighorn habitat each entity owned/managed. Pre-outbreak bighorn population histories are also described. These include details on: population establishment, growth and management, and population size just prior to examined epizootics.

When examining nearby domestic sheep at the time of each outbreak, the location and circumstances of sheep presence are discussed. Proximity to bighorns is addressed along with whether domestic sheep were free-ranging allotment stock, hobby animals, weed control mechanisms, etc. When summarizing case study disease outbreaks, elements addressed are: chronology, disease strains, presumed infection causes, agency responses, and post-outbreak population estimates.

POLICY ANALYSIS
 The policy analysis approach is the most effective way to analyze the bighorn-domestic sheep disease and management issue because it focuses on evolving policy during a period of time in which numerous die-offs occurred and thus provides a better understanding of policies that can improve bighorn health and prevent disease.

Investigating policy documents was an important part of the policy analysis process. Analyses of policy documents include summaries and commentaries on important documents relevant to each outbreak. Sometimes, policy literature that did not fit neatly into the answers to the policy analysis criteria questions is described in the “Policy Documents” section. Bighorn-domestic sheep interaction management policies were analyzed by applying nine criteria (listed below) to each case study location. Criteria are presented as a series of questions with certain sub-questions dependent upon answers. Questions apply to the timeframe up to and including each outbreak.

1.) Were clearly defined buffer zones established to ensure separation of bighorns and domestic sheep?

YES: How large were they?  Did they take topographic barriers into consideration? Were they enforced? If so, how?
NO: Why?

2.) Were special supervision rules in place for sheepherders?

YES: What were they? How were they enforced/presented?
NO: Why?

3.) Were domestic sheep trailing restrictions in place to ensure separation?

YES: What were they? How were they enforced/presented?
NO: Why?

4.) Were policies in place or was consideration taken regarding the concept of prohibiting bighorn reintroduction to the site if it hosted domestic sheep?

YES: What policies were in place or what consideration was taken?
NO: Why?

5.) Before the disease outbreak, was any effort made to buy out nearby domestic sheep grazing allotments or convert them to cattle?

YES: What were the efforts?
NO: Why?

6.) Were other forms of negotiation and/or education attempted with local stakeholders regarding the issue of bighorn-domestic sheep disease transmission?

YES: How?
NO: Why?

7.) If wandering bighorns got too close to domestic sheep, were they ever removed from the wild in or near this location?

YES: What were the circumstances?
NO: Was this policy considered?

8.) Did coordination and/or tension exist between different levels (federal, state, local) of government management agencies regarding bighorn-domestic sheep interaction?

YES: What was the nature of this coordination and/or tension?
NO: Why?

9.) Did you encounter funding difficulties regarding bighorn-domestic sheep interaction management?

YES: What was the nature of these difficulties?
NO: Why?

Policy analysis criteria #1-4 were taken from the 1990 BLM guidelines for domestic sheep management in desert bighorn habitat (DBC Technical Staff 1990). Criteria #5-8 were based on other literature (Hurley et al. 1999; ODFW 2003; Mack 2008). Criterion #4 was not applied to the Tarryall/Kenosha Mountains because this is the only case study location hosting a native bighorn population that was not established through transplants (Toweill and Geist 1999; CDOW 2009; NDOW 2010). Some criteria also ended up not being applicable to certain locations because of a lack of domestic sheep grazing allotments on public land (USFS 2007; Rohrbacher 2012).

For criteria questions presented in the results, answer headings are included below each criterion to provide organization. These headings include: “Answer and Explanation (yes or no and why), “Answer and Implementation” (how policies were enforced/presented), and “Policy” (summaries of and excerpts from actual policies). For criteria #8-9, because of different question tones, answer headings include “Answer and Nature” instead of just “Answer and Implementation.” After certain questions were answered, answer headings sometimes changed based on particular answers. For example, if a certain policy did not exist or was never carried out, “Answer and Explanation” is used instead of “Answer and Implementation,” and “Policy” may not be included if no policy details are available. As illustrated in the list above, the questionnaires submitted to respondents included basic what/how follow-up questions based on yes/no responses. After answering each policy analysis criterion question, a policy efficacy summary is presented for each location.

Criterion #9 (regarding the possibility of funding difficulties) requires some special commentary because it is a more generalized question that does not primarily involve a specific sheep regulation element like most of the other criteria. One might wonder just what types of bighorn-domestic sheep interaction management could have benefited from better funding? For one thing, funding could have determined the level and effectiveness of staff to enforce grazing regulation policies. For example, better funding could have put BLM personnel on the range during sheep drives to monitor their proximity to bighorns. Additionally, funding could also pertain to education efforts regarding wild-domestic sheep interaction. For instance, maybe not enough money is always available to do thorough community outreach to address the threat of hobby domestic sheep. Separation barriers (e.g., electric fences) could also be funded by government money. Additionally, special wild-domestic sheep interaction monitoring programs like that carried out by the City of Missoula (described in the Bonner/West Riverside case study) need funding.

Before contacting agency representatives, many questions were answered or partially answered via literature. Most respondents who were interviewed via e-mail and/or the phone received partially completed questionnaires that contained the questions listed above. These questions often formed entire questionnaires or contributed to questionnaires. They were also the basis of semi-structured phone interviews that sometimes went well beyond the scope of initial questions.

FINDING ANSWERS
 Answers were first sought via literature. State bighorn management plans, national forest plans, and BLM land and resource management plans were particularly helpful. Results of a questionnaire presented to biologists at the 2nd North American Wild Sheep Conference in 1999 were also insightful for gauging general levels of agency coordination and tension that existed in the middle of the study timeframe (Arthur et al. 1999).

When literature left gaps, government agencies were contacted. Before completing case study profiles, contact information was gathered for agency offices near each outbreak location. Agencies contacted included the BLM, U.S. Forest Service (USFS), Colorado Parks and Wildlife (CPW), Montana Department of Fish, Wildlife, and Parks (MFWP), Nevada Department of Wildlife (NDOW), and Oregon Department of Fish and Wildlife (ODFW). Finding contact information for BLM employees was the easiest. BLM district websites have convenient, thorough staff directories that are easy to locate. Contacting USFS and state wildlife agency personnel was more challenging, and contact information was less available.

At least one land management agency and one wildlife management agency were contacted for each location. Varying land ownership patterns dictated what agencies got contacted. For example, for the Tobin Range, just the BLM and NDOW were contacted. However, for Aldrich Mountain, the BLM, Malheur National Forest, Ochoco National Forest, and ODFW were contacted.

In general, when contacting agency personnel, inquiries were first made via phone or e-mail to agency representatives knowledgeable about their colleagues (information and education managers, front desk people, etc.). After asking initial contacts about who might best be able to answer this project’s questions, certain specialists (mainly wildlife biologists and rangeland managers) were contacted until willing questionnaire respondents were discovered. Questionnaires were then sent via e-mail and returned electronically or conveyed verbally on the phone. Some agency personnel were more responsive than others. Some agency people completely ignored inquiries. Other personnel were quickly responsive, and some agency workers responded to follow-up communication initiated several weeks or months after initial contact attempts. A couple of retired agency wildlife biologists also proved particularly helpful.

The Surprise BLM Field Office in northeastern California managed domestic sheep grazing near bighorn habitat in Nevada’s Hays Canyon Range and committed some of the most obvious policy mistakes/violations (Flores, Jr. 2012; BLM 2007a, b). However, surprisingly, personnel at that office were exceptionally responsive and informative compared to other locations.

Not much information was clearly or easily available concerning policy at the time of the Aldrich Mountain die-off because it happened over 20 years ago. However, agency personnel were helpful and even investigated some things on their own. Finding information regarding the Tobin Range was also challenging because it is an obscure location that experienced a disease outbreak over 20 years ago. Nonetheless, contacting a retired NDOW biologist (Gregg Tanner) contributed to significant filling of data gaps for the Tobin Range.

For some of the older outbreaks, just because certain policies were not discovered in this study or known of by some agency personnel does not necessarily mean they did not exist. However, by remaining unknown at this point, certain policies may not have been prominent or important. Finding data concerning the most recent studied disease outbreak locations (Hays Canyon Range and Bonner/West Riverside) was the easiest, and much data exist concerning wild-domestic sheep management in those areas.

DISCUSSION OF RESULTS
 Discussion of results (presented in the Analysis of Case Studies page) focuses on evaluating policy efficacy. The essential question is: What location/policy combinations were the most and least prone to cause or prevent bighorn disease? Some locations had logical policies that were not enforced. Certain policies also did not exist for some regions. Factors like this were considered as the results were analyzed from a comparison perspective to gauge policy efficacy.

For each case study profile category (nearby domestic sheep, disease outbreaks, etc.), tables were made to summarize key findings in a manner that facilitated clear comparisons. With the aid of tables, commentary was then compiled that analyzes the meaning of the results for each category. Results for the nine policy analysis criteria receive individualized commentaries in addition to a summary table covering all criteria. The policy analysis commentaries include discussions of the general policy efficacy of each of the major criteria. Conclusions in these discussions were determined by case study results.

The general criterion efficacy analyses are followed by location-specific commentaries. In these commentaries, some key location results are repeated and summarized to serve as examples illustrating efficacy trends. Policy similarities and differences between locations are also frequently covered. The policy analysis criteria commentaries are followed by some general discussion of overall temporal trends.

REFERENCES
Aune, Keith, Neil Anderson, David Worley, Larry Stackhouse, James Henderson, and Jen’E Daniel. 1998. A comparison of population and health histories among seven Montana bighorn sheep populations. In proceedings of Northern Wild Sheep and Goat Council’s 11th Biennial Symposium, Whitefish, MT. April 16-20.

Arthur, Steven M., Ian Hatter, Alasdair Veitch, John Nagy, Jean Carey, Jon T. Jorgenson, Raymond Lee,  John Ellenberger, John Beecham, John J. McCarthy, Gary Schlichtemeier, Larry T. Gilbertson, Bill Dunn, Don Whittaker, Ted A. Benzon, Jim Karpowitz, George Tsukamato, Kevin Hurley, Steven G. Torres, Craig Mortimore, Mike Oehler, Patrick Cummings, Craig Stevenson, Eric Rominger, and Doug Humphreys. 1999. Appendix A: Wild sheep status questionnaires. In proceedings of 2nd North American Wild Sheep Conference, Reno, NV. April 6-9.

Brigham, William R., Eric M. Rominger, and Alejandro Espinosa T. 2007. Desert bighorn sheep management: Reflecting on the past and hoping for the future. In transactions of Desert Bighorn Council’s 49th Annual Meeting, Las Vegas, NV. April 3-6.

Bureau of Land Management (BLM). 2007a. Proposed Resource Management Plan and Final Environmental Impact Statement: Surprise Field Office, Volumes I and II – May 2007. Cedarville, CA. http://www.blm.gov/ca/st/en/fo/surprise/propRMP-FEIS.html (accessed May 15, 2012). [govt. doc.]

Bureau of Land Management (BLM). 2007b. Tuledad Allotment 2007 Annual Operating Plan. Cedarville, CA. [govt. doc.]

Colorado Division of Wildlife. 2009. Colorado Bighorn Sheep Management Plan: 2009-2019. Edited by J.L. George, R. Kahn, M.W. Miller, and B. Watkins. Denver. http://wildlife.state. co.us/SiteCollectionDocuments/DOW/WildlifeSpecies/Mammals/ ColoradoBighornSheep ManagementPlan2009-2019.pdf (accessed October 15, 2011). [govt. doc.]

Cummings, Patrick J., and Craig Stevenson. 1995. Status of desert bighorn sheep in Nevada – 1994. In transactions of Desert Bighorn Council’s 39th Annual Meeting, Alpine, TX. April 5-7.

Desert Bighorn Council Technical Staff. 1990. Guidelines for the management of domestic sheep in the vicinity of desert bighorn habitat. In transactions of Desert Bighorn Council’s 34th Annual Meeting, Hermosillo, Sonora, Mexico. April 4-6.

Flores, Jr., Elias. 2012. Wildlife Biologist (Surprise District), Bureau of Land Management. Interview by author. Conducted by e-mail. June 28.

George, Janet L., Daniel J. Martin, Paul M. Lukacs, and Michael W. Miller. 2008. Epidemic Pasteurellosis in a bighorn sheep population coinciding with the appearance of a domestic sheep. Journal of Wildlife Diseases 44, no. 2 (April): 388-403.

Hurley, Kevin (moderator), Jon Jorgenson, Helen Schwantje, Craig Foster, Herb Meyer, Amy Fisher, Dave Hacker, Harley Metz, Jim Karpowitz, Melanie Woolever, Dick Weaver, Tim Schommer, Cal McCluskey, Duncan Gilchrist, Jim Bailey, Bonnie Pritchard, Dave Byington, Dave Smith, Bill Foreyt, and Dave Hunter (discussion members). 1999. Open discussion – Are we effectively reducing interaction between domestic and wild sheep? Discussion in proceedings of 2nd North American Wild Sheep Conference, Reno, NV. April 6-9.

Jansen, Brian D., Paul R. Krausman, James R. Heffelfinger, Ted H. Noon, and James C. Devos, Jr. 2007. Population dynamics and behavior of bighorn sheep with infectious keratoconjunctivitus. Journal of Wildlife Management 71, no. 2 (April): 571-575.

Mack, Kurtis M. 2008. Wandering wild sheep policy: A theoretical review. In proceedings of Northern Wild Sheep and Goat Council’s 16th Biennial Symposium, Midway, UT. April 27-May 1.

Montana Department of Fish, Wildlife, and Parks. 2010. Montana Bighorn Sheep Conservation Strategy: 2010. Helena. http://fwpiis.mt.gov/content/getItem.aspx?id =39746 (accessed October 15, 2011). [govt. doc.]

Nevada Division of Wildlife. 2001. Nevada Division of Wildlife’s Bighorn Sheep Management Plan: October 2001. Reno. http://www.ndow.org/about/pubs/plans/bighorn _management_plan.pdf (accessed October 15, 2011). [govt. doc.]

Nevada Department of Wildlife (NDOW). 2008. Bighorn Sheep Die-off in Hay’s Canyon: 2007/2008. N.p. http://www.ndow.org/wild/health/HaysCanyonDieOff2007.pdf (accessed December 18, 2011). [govt. doc.]

Oregon Department of Fish and Wildlife. 2003. Oregon’s Bighorn Sheep & Rocky Mountain Goat Management Plan: December 2003. Salem. http://www.dfw.state.or.us/wildlife/ management_plans/docs/sgplan_1203.pdf (accessed October 15, 2011). [govt. doc.]

Rohrbacher, Art. 2012. Wildlife Program Manager/Acting Planning, Budget & Resources Staff Officer (Beaverhead-Deerlodge National Forest), U.S. Forest Service. Interview by author. Conducted by e-mail from. June 11.

Toweill, Dale E., and Valerius Geist. 1999. Return of royalty: Wild sheep of North America. Missoula, MT: Boone and Crockett Club and Foundation for North American Wild Sheep.

U.S. Forest Service (USFS). 2007. Rocky Mountain Bighorn Sheep (Ovis canadensis): A Technical Conservation Assessment, Prepared for the USDA Forest Service, Rocky Mountain Region, February 12, 2007, by John J. Beecham, Cameron P. Collins, and Timothy D. Reynolds. Rigby, ID. http://www.fs.fed.us/r2/projects/scp/assessments/rockymountainbig hornsheep.pdf (accessed January 7, 2012). [govt. doc.]

Western Association of Fish and Wildlife Agencies (WAFWA). 2010a. WAFWA Wild Sheep Working Group recommendations for domestic sheep and goat management in wild sheep habitat: July 21, 2010. N.p.: WAFWA. http://www.wafwa.org/documents/wswg/WSWG ManagementofDomesticSheepandGoatsinWildSheepHabitatReport.pdf (accessed May 17, 2012).

Western Association of Fish and Wildlife Agencies (WAFWA). 2010b. WAFWA Wild Sheep Working Group summary: Winter 2009-2010 bighorn sheep die-offs (3/16/10). Cheyenne: WAFWA. Web address no longer available (accessed August 23, 2010; based on file info).