Elk Nutrition And Home Range | Rangelands | USU Extension

    Elk Nutrition And Home Range


    Elk - Diets, Competition with Livestock, Home Range Studies

    Nutritional Value of Aspen

    D.E. Jelinski and L.J. Fisher. 1991. Spatial Variability in the Nutrient Composition of Populus tremuloides: Clone-to-Clone Differences and Implications for Cervids. Oecologia 88:116-124.

    Objectives: (1) to examine spatial variability in nutrient concentrations among 24 clones of aspen and (2) to evaluate these differences with respect to elk and deer nutritional requirements.

    Results:

    1. Most clones provided adequate levels of Ca, Mg, Mn, and Zn.
    2. Crude protein was limiting in some clones and P in most.
    3. In some clones, P metabolism may be impaired by high ratios of Ca to P.
    4. Crude protein: CP ranged from 4.56% to 7.44%. Wintering elk require 5-7% CP to meet maintenance. CP requirements for adult deer range between 6% and 9%. Protein requirements for growth are higher ranging from 12-16%. Requirements for CP, Ca, P, and energy, are much higher during the last trimester of pregnancy.
    5. Phosphorus: P varied from 0.13 to 0.21%. Minimum P requirements for deer vary between 0.20 and 0.35%. P requirements for elk are not known. Only one clone had a P content >0.20%. 12 of the 24 clones barely met the minimum P requirement for beef cattle (0.18%). While dietary P might be limiting, winter forage values are probably sufficient given that the animals can use P reserves accumulated during summer.
    6. Calcium ranged from 0.5 to 2.1%. Deer require a diet of 0.4-0.6% Ca. Grasses typically comprise a large part of elk diets but the Ca content of grasses is often below nutritional requirements. Aspen may provide an important supplementary source of this mineral.
    7. Ca:P Ratios: The ideal Ca:P ratio is 1:1 or 2:1 Ca:P ratio that is best for absorption and metabolism of Ca. The Ca:P ratios varied from 3:1 to 13:1 in clones. In general, Ca excesses have comparatively little effect on P absorption, as opposed to excesses of P on Ca absorption. Some Ca may be tied up as insoluble calcium oxalate, thus lowering the effective Ca:P ratio. High Ca:P ratios can be accommodated by many ruminants as suggested by their extensive use of alfalfa. Ratios greater than 7:1-10:1 many reduce availability of P.
    8. Manganese – Mn concentrations varied from 15.4 to 58.3 ppm. Manganese appeared to exceed NRC nutritional requirements (10 ppm), but is unlikely to be toxic at these levels.
    9. Zinc – Zn concentrations varied from 46.4 to 127.0 ppm.
    10. Iron -Fe concentrations varied widely from 35.2 to 150.5 ppm.
    11. Sodium – Na concentrations were too low to meet basic requirements.
    12. Copper concentrations were too low to detect (<10.2 ppm), except for 2 clones, their concentrations averaged 10.5 and 12.2 ppm. Kubota et al. (1970) reported that Cu concentrations in aspen twigs averaged 6.5 ppm. Copper deficiencies are possible. While beef cattle require about 4 ppm, elk seem to have unusually high requirements. If other elements are balanced, 10-15 ppm is probably sufficient for wintering elk.
    13. Fiber - NDF ranged from 39.5 to 52.8%. Elk are superior to deer in their ability to digest NDF. Cellulose contents ranged from 17.43 to 25.73%. ADF ranged from 28.32 to 36.48%. Lignin values ranged from 9.45 to 13.09%.
    14. Dry Matter Digestibility -estimates of DMD derived from the summative equation of Robbins et al. (1987a, 1987b) and ranged from 45.9 to 56.2%. Our estimates of DMD from the summative equation compare with others who found IVDMD of aspen terminal shoots to be 42%. IVDMD for 4, 5 and 6 mm diameter-long shoots from aspen averaged 41% irrespective of twig diameter. Another study estimated that winter aspen twigs averaged 44.9% IVDMD. Overall, aspen is higher in digestibility than most other browse species. 

    Elk Diets - General

    R. C. Kufeld. 1973. Foods Eaten by the Rocky Mountain Elk. J. Range Manage. 26:108-133.

    Forage Value Ranking Winter Spring Summer Fall 
    Quaking aspen 2.50 * 8 2.25 * 4 1.74 + 4 2.50 * 8 
    Ranking symbol: -least valuable; + valuable; * highly valuable Highly valuable plant -One avidly sought by elk; made up a major part of the diet; or was eaten far in excess of its vegetative composition. Ranking of 2.25 to 3.00. Valuable plants-One sought and readily eaten but to a lesser extent than highly valuable plants. They made up a moderate part of the diet. Ranking of 1.50 to 2.24. Least valuable plant-One eaten by elk but made up a minor part of the diet, or was eaten in a much smaller proportion than it occurred on the range. Ranking of 1.00 to 1.49. Note: These above terms are used to reflect the relative value of a plant on elk range from a manager's viewpoint. Value does not consider nutrient quality. 

    W.B. Collins and P.J. Urness. 1983. Feeding behavior and habitat selection of mule deer and elk on Northern Utah summer range. J. Wildl. Manage. 47:646-663.

    Objective: To determine the feeding behaviors and habitat preferences of tame, free-ranging mule deer and elk in quaking aspen and lodgepole pine types.

    Results:

    1. Mule deer and elk exhibited strong grazing preference for open habitat.
    2. Elk preferred highly productive meadow bottoms.
    3. Deer preferred clear-cut lodgepole pine and aspen forest.
    4. Clear-cutting greatly increased deer and elk grazing use in the lodgepole pine type.
    5. Aspen clear-cuts were used at about the same level as uncut aspen.
    6. Elk were better able than deer to use a more diverse array of plant species.
    7. Animals preferred to graze subunits with the highest consumption rates.
    8. Since both species made often used less preferred habitat, where consumption rates were relatively low, suggests that deer and elk explore their environments for alternate food resources.
    9. Elk generally preferred to bed wherever they finished feeding, although always in close proximity to cover.
    10. Mule deer generally retreated to specific beds that they used repeatedly throughout the summer. 
    11. The lack of mule deer use of meadow bottoms was attributed to their need for a more digestible diet. 

    Conclusion: Mule deer were generally more selective than elk, especially in meadow subunits, where density of vegetation and abundance of non-preferred grasses and sedges apparently interfered with forage selection and prevented maximum forage consumption rates. 


    Elk Winter Diets

    Larsen, E.J. and W.J. Ripple. 2005. Aspen stand conditions on elk winter ranges in the northern Yellowstone ecosystem, USA. Natural Areas J. 25:326-338.

    Objective: To test whether lack of overstory aspen recruitment observed in Yellowstone (YNP) extended to winter ranges of elk in adjacent national forests.

    Methods: Remote sensing and field-collected data were obtained from aspen stands in YNP (n = 93), the Gallatin National Forest (n= 63), and the Sunlight/Crandall elk winter range (n = 54) in the Shoshone National Forest.

    Results:

    1. Aspen canopy coverage decline in all sites from the 1950s to the 1990s, but the rate of decline was greater in Yellowstone than in the two national forest sites.
    2. The density of live aspen overstory stems was lower in YNP compared to the two national forest sites.
    3. Live aspen stems less than 4 inches in diameter at breast height were observed in YNP only in stands located in rocky locations, but were commonly observed in the national forest sites. 
    4. In the three study areas, no differences were observed in density of aspen ramets, the percentage of browsed ramets, or the density of conifers within aspen stands.
    5. The two national forest sites had a higher percentage of aspen stands containing ramets greater than 39 inches tall and a lower incidence of bark scarring on overstory aspen stems compared to Yellowstone.
    6. Within YNP, aspen stands on rocky locations had a lower percentage of browsed ramets and more stems in small size classes compared to aspen stands in other habitat types. 

     

    Conclusions: While aspen cover has declined across all sites, the national forest sites have had successful recruitment of replacement overstory aspen stems. Overstory aspen in YNP are recruiting only in areas protected from browsing, such as on very rocky locations. Differences in ungulate densities and foraging behaviors may explain the differences in aspen regeneration observed among the three sites. 

    Romme, W.H., Turner, M.G., Wallace, L.L. and Walker, J.S. 1995. Aspen, elk, and fire in northern range of Yellowstone National Park. Ecology. 76:2097.2106.

    Most stand of trembling aspen northern Yellowstone National Park were likely established between 1870 and 1890 with little regeneration since 1900. Fires in 1988 burned 22% of the northern ungulate winter range in the park.

    Hypotheses:

    1) Fires would stimulate such prolific sprouting of new aspen stems in burned stands that many stems would escape browsing and regenerate a canopy of large aspen stems OR 2) browsing pressure would be so intense that it would inhibit aspen canopy regeneration in the burned stands despite prolific sprouting, but increased forage production in burned areas would attract elk so that they would not seek out remote aspen stands; aspen regeneration would occur in unburned aspen stands remote from the burned areas.

    Methods: We sampled aspen sprout density, height, growth form, and browsing intensity in: 1) six burned aspen stands, 2) six unburned stands close (less than 0.6 miles) to the burned areas and 3) six unburned stands remote (greater than 2.5 miles) from the burned area. 

    Results:

    1. Density of sprouts was greater in burned stands than in unburned stands in spring 1990 (2 yr after the fires), but were approaching the density of unburned stands by fall 1991.
    2. There were no differences in browsing intensity (% aspen sprouts browsed by ungulates) in 1990 or 1991 among burned, unburned close, or unburned remote stands
    3. No differences in browsing intensity based on growth form (juvenile vs. adult).
    4. Sprouts that escaped browsing generally were lower than the depth of the snowpack suggesting that elk browsed nearly all sprouts that were accessible. 

    Conclusions: The age distribution of 15 aspen stands across the northern winter range indicated that regeneration of large canopy stems was an episodic event prior to the establishment of the park in 1872. The period (1870-1890) when present-day aspen stands were generated was historically unique: numbers of elk and other browsers were low, climate was wet, extensive fires had recently occurred, and large mammalian predators (e.g. wolf) were present. This combination of events has not recurred since 1900. The lack of aspen regeneration in northern Yellowstone National Park cannot be explained by a single factor but a complex interaction among factors.

    Christianson, D.A. and S. Creel. 2007. A review of environmental factors affecting elk winter diets. J. Wildl. Manage. 71:164–176.

    Objective: We used data from 72 studies conducted in western North America between 1938 and 2002 to quantify diet selection by elk and to test whether variation in elk diets is associated with habitat type, winter severity, period of winter, human hunting, and study method.

    Results:

    1. Grasses and grass-like plants such as sedges dominated elk diets and occurred at a higher proportion in the diet than in elk foraging habitats, indicating preference.
    2. Forbs were usually less than 5% of the diet, with no evidence for preference. We conclude that forb use is largely incidental to grazing for grasses.
    3. Browse was eaten in proportion to its availability, thus the amount of browse in the diet was primarily determined by habitat rather than selection for browse.
    4. Comparing the diets of elk and other ruminants, elk consistently selected grasses more often than other ruminants with the exception of bison, suggesting that elk are not environmentally forced to adopt the grass-based diet that they normally select.
    5. The proportion of open meadows and grasslands on winter ranges was strongly and positively associated with grass consumption by elk.
    6. The proportion of grasses in the diet was lower during severe winter conditions or predation risk from human hunting.
    7. The period of winter (early, middle, and late) had only small effects on elk diets, as did the method by which the diet was determined. 

    Conclusion: Overall, variation in elk diets is well-explained by a consistent tendency to select grasses, if available, modified by winter habitat type, predation risk, and winter severity, which can constrain habitat selection and access to grazing opportunities. 
    To fully understand variations in foraging behavior, biologists should recognize these broad patterns when interpreting resource selection data. Managers should recognize that diet selection altered by environment probably carry nutritional consequences.

    N.T. Hobbs, D.L. Baker, J.E. Ellis and D.M. Swift 1981. Composition and quality of elk winter diets in Colorado. J.Wildl Manage. 45:156-171.

    SEE SPREADSHEET

    Objective: To relate the botanical composition and nutritional quality of the diets of 5 tame elk to forage quality, advancing season, and plant communities of upper montane winter range.

    Results:

    1. Grasses dominated diets during 1976-77, but declined from 66% of observed bites in November to 44% in February as browse consumption increased.
    2. Browse and grass (accounting for >90% of bites each month) contributed equally to diets through winter 1977-78.
    3. Browse contained more CP, cell solubles, and lignin, and less cellulose and IVDDM than grasses.
    4. Nutritional quality of browse remained constant with advancing season, whereas grasses decreased in IVDDM and CP, and increased in fiber content.
    5. Grasses and browse contained less CP, and browse less IVDDM, during 1977-78 than during the previous year.
    6. From Nov to March 1976-77: dietary CP declined from 5.8 to 4.9%, and IVDDM declined from 49 to 40%.
    7. From Nov to March 1977-78: dietary CP declined from 5.4 to 4.6% and IVDDM from 42 to 37%.
    8. During 1976-77, mean winter dietary CP ranged from 6.3% in dry grassland to 4.6% in mesic meadow communities; dietary IVDDM ranged from 47% in aspen to 35% in grasslands.
    9. During 1977-78, protein was highest (5.6%) in willow and lowest (4.6%) in mesic meadow, and IVDDM was highest (39%) in aspen and lowest (35%) in willow. 


    Conclusions: Despite year-to-year variation in forage quality, elk maintained relatively stable diet quality over time and space by shifting the forage-class mix of diets. 

    Burned and Unburned Aspen Stands

    S.K. Canon, P.J. Urness, and N.V. DeByle. 1987. Habitat selection, foraging behavior, and dietary nutrition of elk in burned aspen forest. J. Range Manage. 40:433-438.

    Objective: to assess diet composition and nutritional quality by free-ranging tame elk (four) on burned and unburned sites.

    Methods: The site contained a 40-ha aspen burn, pure unburned aspen, mixtures of aspen and conifers, and other habitats. Foraging preferences of elk among the habitats were also investigated. Study was conducted between July 12 and August 24.

    Results:

    1. No nutritional differences were found between burned and unburned aspen habitats.
    2. Diet composition by forage class varied somewhat, due primarily to an abundance of very palatable post-fire forbs on the burn.
    3. Elk preferred to eat forbs then browse and very little grass.
    4. Elk ate very little aspen, but consumed a large proportion of serviceberry.
    5. Time spent feeding was significantly different among habitats.
    6. The burn was substantially more attractive for foraging probably because preferred forages were consistently available and greater foraging efficiency was possible than in other habitats.
    7. Elk did not forage in the meadow after August 7 

    Competition between Wild and Domestic Herbivores

    Beck J.L and J.M. Peek. 2005. Diet composition, forage selection, and potential for forage competition among elk, deer, and livestock on aspen–sagebrush summer range. Rangeland Ecol Manage 58:135–147

    SEE SPREADSHEET

    Objective: 1) to evaluated elk, mule deer, cattle, and domestic sheep diet composition, diet overlap, and forage selection on aspen–sagebrush summer range in northeastern Nevada and 2) to understand potential for forage competition to provide better information for managing these communities.

    Methods: Diets were determined through microhistological fecal analysis from 1998 to 2000, and forage selection was evaluated at feeding sites in aspen and sagebrush communities in 1999 and 2000. Study conducted in Northeast Nevada.

    Results:

    1. Elk spring diets were the most diverse in plant composition.
    2. Summer elk diets were dominated by forbs (59%–78%).
    3. Deer ate mostly woody browse (64%–72%).
    4. Cattle and sheep ate mostly grasses.
    5. In the summer, lupines constituted >11% of elk, deer, and sheep diets.
    6. Spurred lupine was typically selected in feeding sites and greatest consumption occurred in summer when total alkaloid levels were lowest.
    7. Highest diet overlap was between cattle and sheep in 1999 (68%) and
    8. Lowest between deer and cattle in 2000 (3%).
    9. Summer elk and deer diets overlapped moderately (45%–59%).
    10. Diets did not differ between elk in spring with sheep, elk in summer with deer and sheep, or cattle with sheep.
    11. Cattle foraged selectively on forbs in aspen communities (68%) and on grasses in sagebrush communities (88%), reflecting relative forage availabilities.
    12. We detected no differences among elk, cattle, and sheep for forage selection in aspen communities.
    13. Electivity indices indicated elk preferred forbs in aspen and sagebrush communities; Cattle preferred grasses in sagebrush; Foraging sheep preferred forbs in aspen.

    Conclusions: Our results suggest potential for forage competition among ungulates on aspen–sagebrush summer range is highest for forbs in aspen communities. Monitoring productivity and use of key forage species, particularly forbs in aspen communities, should complement management objectives on shared aspen–sagebrush summer range.

    J.L. Beck, J.T. Flinders, D.R. Nelson, and C.L. Clyde. 1996. Dietary Overlap and Preference of Elk and Domestic Sheep in Aspen-Dominated Habitats in North-Central Utah. In: K.E. Evans. Sharing common ground on western rangelands: Proceedings of a livestock big game symposium. Gen. Tech. Rep. JNT-GTR. 343. Ogden, UT: USDA-F, Intermountain Research Station. Sparks, NV February 26-28.

    Elk Elk Elk Sheep Sheep 
    Spring Summer Fall Spring Summer Aspen 0.53 0.42 0.26 -0.54

    Objective: To determine dietary overlap and preferences of elk and domestic sheep sharing a common 25,000-acre range dominated by aspen in north-central Utah for May-October 1994. 

    Results:

    1. Mean dietary overlap was 36.4 ± 32.S percent in summer, and 40.5 ± 37.1 percent in fall.
    2. CP was the most consistent nutritional component influencing variation in elk preference for forage.
    3. TNC were the most consistent nutritional fraction influencing sheep selection of forages.
    4. Natural mineral licks provided essential elements, including Mg for elk in the study area.
    5. Salt for sheep was lacking in Mg, and during summer, sheep exhibited a preference for Mg-rich forages. 

    Conclusion: Changes in availability of important minerals such as Na and Mg are hypothesized to cause changes in dietary overlap because this may cause elk and sheep to select different forages.

    How Grazing Systems Influence Elk Distributions

    S.J. Werner and P.J. Urness. 1996. Elk Herbivory, Rest-Rotation Grazing Systems, and the Monroe Mountain Demonstration Area in South-Central Utah: A "Seeking Common Ground" Initiative. In: Sharing Common Ground on Western Rangelands: Proceedings of a Livestock/Big Game Symposium Keith E. Evans (ed.) Intermountain Research Station, USDA Forest Service 

    Introduction: In cooperation with the Monroe Mountain Common Ground initiative, the Monroe Mountain Livestock/Big Game Demonstration Area was selected to facilitate the resolution of conflicts between livestock and big game interests in south-central Utah.

    Objective: To determined elk distribution and forage utilization within a rest-rotation grazing system on Monroe Mountain.

    Results:

    1. Elk did not consistently prefer rested grazing units during the 1993, 1994, and 1995 domestic livestock grazing seasons.
    2. Elk forage utilization ranged from 9.5 to 30.2% in June and 12.0 to 18.6% in August on two grazing units.
    3. Although elk forage utilization within the Koosharem grazing allotment was greater in 1995 than in 1994, 41.6 to 57.1 percent more June to August forage regrowth occurred within this allotment during the relatively wet year of 1995.

    Conclusion: The interspecific relationships of cattle and elk within the sampled restoration grazing system appear to be other than competitive. 

    S.J. Werner and P.J. Urness. 1998. Elk Forage utilization within rested units of rest-rotation grazing systems. Journal of Range Management 51:14-18.

    Background: Elk have been repeatedly observed to prefer rested units within rest-rotation grazing systems. Given the logistical and financial investments associated with the maintenance of these systems, elk herbivory within rested units is a potential source of conflict.

    Objective: To determine elk forage utilization during the summers of 1994 and 1995 in a forest-grassland of 3 rest-rotation grazing allotments in south-central Utah's Fishlake National Forest. Note: The 1995 grazing season began with a relatively wet spring (81% more precipitation than the 1957 to 1993 spring average).

    Results:

    1. In 1994, no differences in biomass between caged and uncaged plots were detected.
    2. In 1995, biomass in caged plots was greater than in uncaged plots browsed by elk in 2 of 3 rested units in June-July (14.1 and 35.6% utilization) and August (34.7 and 42.0% utilization).
    3. June-to-August forage growth or regrowth in 1995 was 31.3% greater in caged plots and 33.0% in uncaged plots compared to1994.
    4. Within pastures rested from cattle grazing, the differences of average biomass clipped within caged and uncaged plots ranged from -80.0 to 2.5kg/ha in June 1994 and 142.5 to 610.0 kg/ha June-July 1995.
    5. Average biomass differences during the August from -127.5 to 67.5 kg/ha in 1994 and 187.5 to 1075.0 kg/ha in 1995.
    6. Forage utilization by elk was 14.1% Burnt Flat and 35.6% Ranger Pasture units during June-July 1995. Forage utilization by elk was 34.7% in the Ranger Pasture and 42.0% in the Skumpah unit during August 1995.
    7. Trespass livestock were repeatedly seen within the Skumpah unit during the 1995 grazing season, thus forage utilization attributed to elk may have been over-estimated for this unit in August 1995

    Bailey, A.W., B.D. Irving, and R.D. Fitzgerald. 1990. Regeneration of Woody Species Following Burning and Grazing in Aspen Parkland. Journal of Range Management 43:212–15.

    Objective: To determine the effect of short duration, heavy grazing by cattle 3 and 6 years after burning and seeding an aspen grove.

    Methods: Replicated paddocks of June grazed (early), August grazed (late), and ungrazed treatments were established.

    Results:

    1. Regardless of grazing treatment, density of all woody species was lower 6 years after burning than after 3 years.
    2. Early or late season grazing reduced the density of aspen and wild raspberry.
    3. Late season grazing promoted a greater density western snowberry.
    4. Grazing reduced the height of aspen, preventing the development of a forest canopy.
    5. Herbage production averaged 1,700 kg/ha and did not differ 3 and 6 years after burning.
    6. Over time the proportion of smooth brome increased while orchard grass declined.

    Conclusion: Burning of aspen forest in Central Alberta followed by forage seeding and short duration, heavy grazing is an effective, economical range improvement tool. 

    Elk Home Ranges

    Benkobi, L., M.A. Rumble, C.H. Stubblefield, S.R. Gamo, and J.J. Millspaugh. 2005. Seasonal migration and home ranges of female elk in the Black Hills of South Dakota and Wyoming. The Prairie Naturalist. 37: 151-166.

    Home Range 
    km2 Acres  
    Summer Northern 99.7 ± 4.2 24,636  
    Summer Southern 163.2 ± 6.0 40,328 

    W. Daniel Edge, C. Les Marcum and Sally L. Olson. 1985. Effects of Logging Activities on Home-Range Fidelity of Elk. Journal of Wildlife Management. 49:741-744.

    Home Range: Hectares Acres Undisturbed 4418 8834 Disturbed 4506 9012 

    Hershey, T.J., and T.A. Leege. 1982. Elk movements and habitat use on a managed forest in north-central Idaho. Idaho Dept. Fish Game Wildl. Bull. 10. 24 pages.

    Home-range fidelity is advantageous to elk, probably because it imparts knowledge about seasonal availability of forage and cover. All elk showed a significant degree of fidelity to their home ranges from year to yea regardless of disturbance, phenological conditions, and changing weather. 

    W. Daniel Edge, C. Les Marcum, Sally L. Olson and John F. Lehmkuhl. 1986. Nonmigratory Cow Elk Herd Ranges as Management Units. Journal of Wildlife Management 50: 660-663.

    Results:

    1. Cow elk using the Chamberlain Creek drainage separate into two distinct herds, a northeastern herd and a southwestern herd.
    2. There were low rates of dispersal and inter-herd movements.
    3. Based upon hunter returns, 3 of 94 (3.1%) cow elk captured in these 2 herds dispersed from traditional herd ranges.
    4. One of 59 (1.7%) radio-collared elk dispersed from the traditional herd range.
    5. Four of 58 (6.9%) radio-collared elk that remained in the study area made a temporary moved between herds.
    6. These movements accounted for only 11 of 2,467 (0.4%) radio-locations.
    7. Bull elk dispersed at a higher rate than cows.
    8. Eight of the 20 (40%) bulls captured from the two herds, were killed by hunters outside the study area, <125 km away.
    9. Interherd movements were not calculated for bulls because too few were radio-collared to define bull herd ranges.
    10. Herd range area varied between the 2 cow herds although, based on annual surveys, both herds contained approximately the same number of elk.
    11. The 7-year mean herd range area for the northeastern herd (f = 81.5 km2) was smaller than the mean for the southwestern herd (f = 142.4 km2). 


    Home Range km2 Acres Summer Northern 81.5 20,136 Summer Southern 142.5 35,200

    Fred van Dyke and Wendi C. Klein. 1996. Response of Elk to Installation of Oil Wells. Journal of Mammalogy 77:1028-1041.

    Results:

    1. Distances between individually marked elk did not differ across periods, suggesting that drilling did not affect the social stability of elk.
    2. Use of forest habitats in autumn increased after initiation of drilling.

    Conclusion: Elk compensated for site-specific environmental disturbance by shifts in use of range, centers of activity, and use of habitat rather than abandonment of range.

    W. David Walter, David M. Leslie, Jonathan A. Jenks. 2006. Response of Rocky Mountain Elk (Cervus elaphus) to Wind-power Development. The American Midland Naturalist 156:363-375

    Results:

    1. The largest composite home range sizes (>80 km2) occurred April–June and September, regardless of the status of wind-power facility development.
    2. The smallest home range sizes (<50 km2) typically occurred in October–February when elk foraged on winter wheat.
    3. No elk left the study site during the study and elk freely crossed the gravel roads used to access the wind-power facility.
    4. Carbon and nitrogen isotopes and percent nitrogen in feces suggested that wind-power development did not affect nutrition of elk during construction.

    Conclusion: Although disturbance and loss of some grassland habitat was apparent, elk were not adversely affected by wind-power development as determined by home range and dietary quality.

    Ryan A. Long, Janet L. Rachlow, and John G. Kie. 2009. Sex-Specific Responses of North American Elk to Habitat Manipulation. Journal of Mammalogy 90:423-432

    Results:

    1. In spring, females preferred 4-year-old burns and used 2-and 3-year-old burns in proportion to their availability.
    2. Males avoided all fire-treated stands.
    3. Control stands were avoided by females but selected by males during spring.
    4. In summer, control stands were selected and treatment stands either were avoided or used in proportion to their availability by the sexes.
    5. Mean overlap of utilization between the sexes was higher in summer than spring.

    Conclusion: Fuels-reduction treatments at Starkey may have increased foraging opportunities for female elk in spring, but were likely of little benefit to male elk.