Population Status and Trends of Big Game and Greater Sage- Grouse in Southeast Montana and Northeast Wyoming
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Population Status and Trends of Big Game and Greater Sage- Grouse in Southeast Montana and Northeast Wyoming Photograph by John Ellenberger Mule Deer Buck July 2015 Population Status and Trends of Big Game and Greater Sage- Grouse in Southeast Montana and Northeast Wyoming Prepared for the National Wildlife Federation And Natural Resources Defense Council By: John H. Ellenberger [email protected] & A. Eugene Byrne [email protected] of Wildlife Management Consultants And Associates, LLC 566 36 Road Palisade, Colorado 81526 (970) 270-6082 www.wlmgt.com 2 EXECUTIVE SUMMARY The National Wildlife Federation retained Wildlife Management Consultants and Associates, LLC to gather and analyze data for deer, elk, pronghorn and greater sage-grouse populations that occupy portions of southeastern Montana and northeastern Wyoming. Specifically, the study area includes the portion of Montana bounded on the north by Interstate 94, O’Fallon Creek and US Highway 12; on the east by the North Dakota and South Dakota state lines; on the south by the Wyoming state line and on the west by Interstate 90 and State Highway 47, with the exception of lands included in Northern Cheyenne and Crow Indian Reservations. The study area also includes the portion of Wyoming bounded on the north by the Montana state line; on the east by the South Dakota state line; on the south by US Highway 20 and the North Platte River and on the west by Interstate Highways 25 and 90. Furthermore, we were requested to prepare a report of our analysis of these data that would “interpret trends in populations and harvest and provide insight into challenges to the populations’ viability.” One goal of the report was to determine which populations may be sensitive or vulnerable to habitat loss or degradation caused by development. For the purpose of this report, development includes, but is not limited to, coal mining, drilling for oil and gas, wind power, electrical transmission lines and natural gas pipe lines, urbanization and cultural development and habitat conversion (e.g., chemical or mechanical treatment of sagebrush habitat to increase grasses and herbaceous vegetation). This report is intended to provide information for sportsmen and the general public about the status of mule deer, elk, pronghorn and greater sage-grouse populations in the above mentioned areas, especially as it relates to hunting recreation and watchable wildlife opportunities. Inventory and harvest data for mule deer, elk, pronghorn antelope, and greater sage-grouse from Montana Fish, Wildlife and Parks and Wyoming Game and Fish Department were used for the analysis. The time frame for the analysis began in 1980 and continued through 2012 and 2013 in some instances. Once the raw data was obtained from the 2 wildlife agencies, it was entered into excel spread sheets to facilitate comparisons and analyses. Big game data used in the analyses included the following; male harvest and total harvest for all seasons and methods of take, total hunters, hunter success rates, herd composition data (males/100 female ratios and young/100 female ratios) and annual estimates of population size for each herd unit or hunting district. The data were used to calculate the following products for each category listed above (total harvest is used here as an example); maximum harvest, minimum harvest, average harvest for all years and average harvest by decade. In addition, excel was used to calculate long-term trends for the data via linear regression. Charts were created using excel to provide a graphic display of the data for population size, male/100 female ratios, young/100 female ratios, male harvest, total harvest, total hunters, and hunter success rates. Throughout this report we have described the vulnerability of deer, pronghorn and greater sage- grouse populations and to a lesser extent elk to stochastic events such as severe winters and drought. As human development causes additional impacts to wildlife habitat these populations are forced to exist on less habitat or lower quality habitat then has existed in the past in addition to coping with the natural variation that occurs in the habitats and environments they occupy. Analysis of data for 27 big game herd units or hunting districts was completed for this project, 8 mule deer, 7 elk and 12 pronghorn. In addition, a review of information and data was completed for 2 greater sage-grouse management areas. For big game we used information from the literature and our professional experience and opinions to evaluate the status of the big game herds. 3 Information that we evaluated for each herd unit (Wyoming) and hunting district (Montana) included the following: • 2012 values for young/100 female ratios and a comparison to the long-term average for young /100 female ratios. • Long-term trend for young/100 female ratios. • 2012 values for male harvest and a comparison to the long-term average for male harvest. • Long-term trend for male harvest. • 2012 values for total hunters and a comparison to the long-term average for total hunters. • Long term trend for total hunters. • To a lesser extent, estimates for population size were also assessed and were compared to established population objectives for each herd, when available. Of the big game species addressed in this analysis, mule deer and pronghorn appear to be the most vulnerable. Deer and pronghorn populations analyzed in this report have either shown declines in population size or productivity or both in the past 32 years. Such declines have direct impacts on hunters and hunting opportunity in the form of lower hunter success rates, decreased harvest, possible decreases in trophy quality of animals harvested and more conservative hunting seasons. We have significant concerns that losses of habitat due to development will result in further reductions in populations and productivity of the deer and pronghorn herds in question, resulting in increasingly conservative hunting seasons and lower numbers of available licenses. We believe that elk are not as vulnerable as mule deer and pronghorn to habitat loss or degradation due to development. This is probably due to their broader food habits and adaptability (Hanley and Hanley 1982 and Thompson and Henderson 1998). However, a likely result of development on public lands will be displacement of elk from seasonal ranges or shifts in periods of use of these seasonal ranges. Displacement of animals will likely result in increased use of private lands by elk resulting in increasing levels of conflict. Increased conflicts often results in increases in game damage or more demands for reductions in elk populations by private land owners which will, in the long run, mean less hunting opportunity. Mule Deer Eight mule deer herds were examined in this analysis, 3 in Montana and 5 in Wyoming. Of the 8 herds evaluated only 1 was judged to be in good condition, Wyoming herd unit 751 (Black Hills). Five herds were judged to be in fair condition; Montana hunting districts 702 (Yellowstone Pine Hills), 704 (Powder Pine Hills) and 705 (Prairie/Pines-Juniper Breaks) and Wyoming herd units 319 (Powder River) and 755 (North Converse). Wyoming herd units 320 (Pumpkin Buttes) and 740 (Cheyenne River) were considered to be in poor condition. Three herds had additional problems or issues. Wyoming deer herd units 319 (Powder River), 320 (Pumpkin Buttes) and 740 Cheyenne River) had short-term trends of 3-5 years of recent declines in population size along with log-term declines for recruitment (young/100 females). These populations are especially vulnerable to additional habitat loss or degradation. If habitat loss or degradation occurs with these 3 herd units, increases in population size are unlikely or very slow to occur. 4 Table 1. Summary of mule deer population data and trends Unit Obj. Pop. 2012 Pop. Size Avg. Pop. Size Trend Pop. 2012 Yng./100 Fem. Avg. Yng./100 Fem. Yng./100 Fem. Trend 2012 Male Harvest Harvest Male Avg. Male Harvest Trend 2012 Total Hunters Hunters Total Ave. Trend Hunter Total Rating Herd M-MD-702 NA 105 153 D 84 68 I 877 1,083 D 2,416* 2,656 D F M-MD-704 NA 538 524 S 63 69 D 1,574 2,238 D 4,695* 4,841 I F M-MD-705 NA 492 447 I 56 66 D 1,553 1,937 D 4,141* 5,008 D F W-MD-319 52,000 36,300 45,490 I 75 68 D 2,036 3,191 D 3,602 5,826 D F W-MD-320 13,000 9,600 11,117 S 64 69 D 633 729 D 1,046 1,467 D P W-MD-740 38,000 17,367 29,150 I 44 74 D 1,255 2,339 D 2,511 4,719 D P W-MD-751 20,000 19,505 20,040 I 76 74 I 1,253 1,917 D 3,569 5,845 D G W-MD-755 9,100 6,004 8,294 I 75 75 D 332 568 D 550 1,057 D F Unit explanation - M-MD-702 = Montana mule deer hunting district 702 W-MD-319 = Wyoming mule deer, herd unit 319 Trend: I - increasing, S - stable, D - decreasing Herd Rating: G - good, F - fair, P - poor NA - not applicable ND - no data * 2011 data Population estimates are for a Montana trend count area that is smaller in size than a hunting district Seven elk herds were evaluated in this analysis, 3 in Montana and 4 in Wyoming. Five of the 7 herds didn’t receive a rating due to incomplete data. Readers that are interested in these hunting districts or herd units should refer to the detailed evaluations for each of them in the body of the report and tables for each herd unit in the appendix.