Big Game Winter Range Research Articles

Livestock Grazing Effects on Forage Quality of Elk Winter Range

Carefully-managed livestock grazing has been offered as a tool to improve the forage quality of graminoids on big game winter range. Formal testing of this theory has thus far been done using hand clippers rather than livestock grazing. We report winter standing reproductive culm, crude protein, in vitro dry matter digestibility, and standing crop responses of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. &Smith), Idaho fescue (Festuca idahoensis Elmer), and elk sedge (Carex geyeri Boott) to late-spring domestic sheep grazing. The study was conducted in 1993 and 1994 on a big game winter range in the Blue Mountains of northeastern Oregon. Sheep grazing and exclusion treatments were applied to 20-ha plots at 3 sites on the study area Targeted utilization for grazed plots was 50% graminoid standing crop removal during the boot stage of bluebunch wheatgrass. Grazing did not influence the number of standing reproductive culms per plant in bluebunch wheatgrass. Crude protein and in vitro dry matter digestibility of bluebunch wheatgrass in grazed plots increased by 1.0 and 4.3 percentage points, respectively over ungrazed plots. Grazing reduced the standing crop of bluebunch wheatgrass by 116.9 kg ha-1 DM. Standing Idaho fescue reproductive culms decreased by 0.7 culms plant-1 under grazing. Crude protein of Idaho fescue in grazed plots was 1.3 percentage points greater than in unglazed plots. Crude protein and in vitro dry matter digestibility responses of elk sedge were inconsistent between years and may be related to utilization or growth differences between years. The levels of forage quality improvement in bluebunch wheatgrass and Idaho fescue obtained in this study could benefit the nutritional status of wintering Rocky Mountain elk (Cervus elaphus nelsoni Bailey). More research is needed regarding the effects of grazing on the winter forage quality of elk sedge. DOI:10.2458/azu_jrm_v53i1_clark

Livestock grazing effects on forage quality of elk winter range

Carefully-managed livestock grazing has been offered as a tool to improve the forage quality of graminoids on big game winter range. Formal testing of this theory has thus far been done using hand clippers rather than livestock grazing. We report winter standing reproductive culm, crude protein, in vitro dry matter digestibility, and standing crop responses of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. Smith), Idaho fescue (Festuca idahoensis Elmer), and elk sedge (Carex geyeri Boott) to late-spring domestic sheep grazing. The study was conducted in 1993 and 1994 on a big game winter range in the Blue Mountains of northeastern Oregon. Sheep grazing and exclusion treatments were applied to 20-ha plots at 3 sites on the study area Targeted utilization for grazed plots was 50% graminoid standing crop removal during the boot stage of bluebunch wheatgrass. Grazing did not influence the number of standing reproductive culms per plant in bluebunch wheatgrass. Crude protein and in vitro dry matter digestibility of bluebunch wheatgrass in grazed plots increased by 1.0 and 4.3 percentage points, respectively over ungrazed plots. Grazing reduced the standing crop of bluebunch wheatgrass by 116.9 kg ha-1 DM. Standing Idaho fescue reproductive culms decreased by 0.7 culms plant-1 under grazing. Crude protein of Idaho fescue in grazed plots was 1.3 percentage points greater than in unglazed plots. Crude protein and in vitro dry matter digestibility responses of elk sedge were inconsistent between years and may be related to utilization or growth differences between years. The levels of forage quality improvement in bluebunch wheatgrass and Idaho fescue obtained in this study could benefit the nutritional status of wintering Rocky Mountain elk (Cervus elaphus nelsoni Bailey). More research is needed regarding the effects of grazing on the winter forage quality of elk sedge.

Effect of Grazing Horses Managed as Manipulators of Big Game Winter Range

A sagebrush-grass range in northern Utah, a critical winter area for deer and elk, was grazed by domestic horses in order to evaluate their potential to reduce selectively herbaceous vegetation which competes with bitterbrush (Purshia tridentata), an important big game winter forage. The diets of horses were recorded during spring and summer grazing under two stocking levels on small pastures. Horses consumed largely grass species throughout the study period in this high seral community. Forbs were important forage only under heavy stocking. No use of bitterbrush was recorded. Rate of forage disappearance, expressed on a peranimal-weight basis, was found to be lower on heavily stocked pastures. All pastures grazed by horses responded with increased seasonal twig production of bitterbrush over the non-grazed state. Seasonal twig production was greatest in response to heavy stocking during early July. Herds of migratory mule deer (Odocoileus hemionus hemionus) and elk (Cervus elaphus nelsoni) in the Rocky Mountains and Great Basin often rely on foothill rangelands dominated by big sagebrush (Artemisia tridentata) and other more palatable shrubs for winter browse. Winter deer mortality in Utah appears to be inversely related to the amount of palatable browse species available (Robinette et al 1952). Bitterbrush supplies important browse on many big game winter ranges in this area. Much of present bitterbrush range in our western states is considered to be seral communities created and maintained by perturbations of some sort (Ellison 1960). Extensive livestock grazing on palatable grasses and forbs in the late 1800’s and early 1900’s led, in part, to widespread successional changes favoring bitterbrush, which was frequently subordinate in the pristine vegetation (Hull and Hull 1974). In response to an increase in palatable shrubs and intensive management, elk and deer prospered by mid-century. In recent years, increasing urbanization near many foothill winter range areas has promoted a trend towards protection of big game winter range from livestock use because of water quality and soil erosion concerns. On many protected rangelands, succession is now favoring grasses since they receive little use during the growing season to balance heavy winter use of shrubs by big game (Smith 1949, Urness 1976). As palatable shrubs disappear from the community, productivity of these lands as deer winter habitat decreases. Declines in the Intermountain Region of deer herd productivity in the mid-1970’s (Connolly 1981) may have been partially due to these plant community changes. It is well recognized that controlled livestock grazing can be used in a manipulative sense to direct plant community succession (Anderson and Scherzinger 1975, Lewis 1969). Research with catAt the time of the research authors were graduate research assistant and associate professor, Range Science Dept., UMC-52, Logan, Utah 84322. Reinerisnow research assistant Range and Wildlife Manage. Dep., Texas Tech Univ. Lubbock, 79409. The authors wish to acknowledge Charles H. Jensen for his advice on the study design and layout. Statistical analysis was assisted by Dr. Ronald V. Sisson and Mr. David L. Turner. Thanks are also due to John Moody and Deborah Bowdenfortheir help in collecting the field data, and to the Starwood Ranch, Aspen, Cola., for generously loaning the study animals. The study was supported in part by the Utah Division of Wildlife Resources, Project W-105-R. Manuscript received August 20, I98 I. JOURNAL OF RANGE MANAGEMENT 35(5). September 1982 tle and sheep has shown that the productivity of bitterbrush can be increased by springtime grazing of competing herbaceous vegetation (Smith and Doe11 1968, Jensen et al. 1972, Smith et al. 1979). One problem encountered when using sheep or cattle for this purpose is that both animals consume bitterbrush. Smith and Doe11 (1968) found that on moderately stocked pastures bitterbrush utilization by cattle increased dramatically in July, in some cases exceeding utilization of grasses. Jensen et al. (I 972), in developing guidelines for sheep grazing on big game winter range, also reported heavy use of bitterbrush beginning in July. Both investigations suggested that stocking and season ofhvestock use must be precisely controlled to avoid excessive utilization of bitterbrush. The use of horse grazing as a “biological tool” to enhance bitterbrush on big game winter range was investigated in this study because horses were presumed to select for grass species (Stoddart et al. 1975, p. 257, Wagner 1978). The objectives of this study were twofold: (1) to investigate the use of spring-summer horse grazing as a means of increasing the seasonal production of bitterbrush, and (2) to determine the effect of grazing season and stocking intensity on the diets of horses grazing sagebrush-grass rangeland.

Diets of Domestic Sheep and Other Large Herbivores in Southcentral Colorado

Diets of Domestic Sheep and Other Large Herbivores in Southcentral Colorado

Response of Curlleaf Mountain Mahogany to Pruning Treatments in Northern Utah

Production of curlknf mountain mahogany (Cercocarpus Iedifoliur) within browsing height of big game on winter ranges was increased 500-900% when 90-99% of the canopy was pruned from mature trees. However, since ndventitioussproutingdidnot occur, numerous live twigs must he present in the browsing zone before treatment for any practical benefit to accrue. Pruning at less than 90% canopy removal and girdling showed positive but smaller vegetative responses, while 100% canopy removal and application of pruning paint to wound surfaces in an attempt to eliminate sap flow had no effect on forage production available to big game. Improvement of the forage resource on big game winter range is one method to compensate partially for past and present reductions in habitat caused by human encroachment. Improvement can be via range restoration through reductions of competing low-value vegetation and reseeding, or improvement of existing, on-site conditions through intensified management. Methods found to increase the forage yield of desirable range plants become potential management tools (Plummer et al. 1968). Curlleaf mountain mahogany (Cercocarpus ledifolius) occurs throughout most of the Intermountain Area as part of the mountain brush zone. It is usually associated with true mountain mahogany (Cercocarpus montanus) at lower elevations and often grades into Douglas-fir (Pseudotsuga menziesii). When foliage is within the browsing reach of deer and elk, intensive utilization reduces available forage by shifting the competitive growth advantage to the upper unused portions. It has been shown to be high in nutritive value (Smith 1952; Bissell and Strong 1955), palatability (Smith 1950; Hoskins and Dalke 1955), digestibility (Smith 1957a), and dietary importance (Mitchell 1951; Smith and Hubbard 1954). Unfortunately, in many mature stands, most of the production is unavailable except through occasional snow or wind breakage of limbs. Thus a practical means of reducing canopy height while retaining productivity of these low trees could be highly beneficial to big game. Revegetation with curlleaf mountain mahogany is generally impractical because oflow seed viability(Younget al. 1978), poor seedling survival (Holmgren 1954) eve” with hand-planted nursery stock (Brown and Martinson 1959), and slow growth (Plummer et al. 1957). Likewise, bulldozing of mature trees has been unsuccessful due to high mortality (Dealy 197 I). Pruning has been found to stimulate vegetative growth in many shrubby species (Ferguson and Basil 1966; Plummer 1974), with variable success for curlleaf mountain mahogany (Smith 1957b; Phillips 1970); Thompson 1970). I” s”mmary, a successful methodology has not yet been defined, “or has the magnitude of change m available production been determined under various intensities and methods of treatment. These were the objectives of this study.

A Comparison of Twig-Length and Browsed-Twig Methods of Determining Browse Utilization

Highlight: Utilization of shrubs has been determined by several techniques, two of which are: (1) measuring twig lengths before and after use then calculating the percentage and (2) estimating the percentage of browsed twigs. Estimates were checked for accuracy by actually counting the number of browsed and unbrowsed twigs and then calculating percentages. The two methods were compared on a big game winter range in southcentral Utah to evaluate the agreement among utilization estimates, consistency among individual observers, and efficiency. Estimating the percentage of browsed twigs or calculating percentages from counts of browsed and unbrowsed twigs provided higher utilization values than measuring twig lengths. Disadvantages of estimating percentages of browsed twigs include the introduction of individual bias when estimates are made and lack of sensitivity in accurately determining percentage utilization under heavy use. By contrast, calculating percentages of utilization from twig length measurements provided equal sensitivity throughout the 0 to 100% range. Twig measurement data were more consistent among observers than estimates. Measuring twig lengths required about four times as many man-hours as estimating percentages of browsed twigs or counting twig numbers.

Response of Big Game Winter Range Vegetation to Fertilization

Highlight: Nitrogeni and phosphorus, alone and in combi; ation, were applied to bitterbrush (Purshia tridentata) and sagebrush (Artemisia tridentata) and three herbaceous species, beardless wvheatgrass (Agropyron inerme), prairie Junegrass (Koeleria cristata), and Pacific aster (Aster chilensis). Spring applications of nitrogen significanitly increased forage production of the three herbaceous species; twig growth, seed production, and percent crude protein of the leaves and twigs of bitterbrush and sagebrush were increased also. Throughout the winters of 1972-73 and 197374, the nitrogen-fertilized bitterbrush and sagebrush plants were used more heavily by elk than the unfertilized plots. Neither yields nor utilization were increased by phosphorus.

Determinants of Spatial Distribution of Rocky Mountain Bighorn Sheep

Determinants of Spatial Distribution of Rocky Mountain Bighorn Sheep

Three Methods of Determining Diet, Utilization, and Trampling Damage on Sheep Ranges

GARRISON, G. A. 1953. Effects of clipping on some range shrubs. J. Range Manage. 6:309-317. HOLMGREN, A. H., AND J. L. REVEAL. 1966. Checklist of the vascular plants of the Intermountain Region. U.S. Forest Serv. Res. Paper INT.-32. 160 p. HORMAY, A. L. 1943. Bitterbrush in California. U.S. Forest Serv., Calif. Forest and Range Exp. Sta. Res. Note 34. 12 p. LAYCOCK, W. A. 1967. How heavy grazing and protection affects sagebrush-grass range. J. Range Manage. 20:206213. NEFF. D. J. 1963. The effect of use on the vigor of browse plants. Job. Compl. Rep., Fed. Aid Project No. PRW78-R., Ariz. Game and Fish Dep. Processed. 8 p. + XII. PECHANEC, J. F., AND G. D. PICKFORD. 1937a. A weight estimate method for the determination of range or pasture production. J. Amer. Soc. Agron. 29:894-904. PECHANEC, J. F., AND G. D. PICKFORD. 1937b. A comparison of some methods used in determining percentage utilization of range grasses. J. Agr. Res. 54:753-756. SMITH, A. D. 1949. Effects of mule deer and livestock upon a foothill range in northern Utah. J. Wildl. Manage. 13:421-423. SMITH, A. D., AND D. M. GAUFIN. 1950. The use of movable paddocks in the study of forage preferences of mule deer and livestock. Tran. N. Am. Wildl. Conf. 15:512518. SMITH, A. D., AND D. D. DOELL. 1968. Guides to allocating forage between cattle and big game on big game winter range. Utah State Div. of Fish and Game Publ. 68-11. 32 p. SMITH, A. D., AND P. J. URNESS. 1962. Analysis of the twig length method of determining utilization of browse. Utah State Dept. of Fish and Game Publ. 62-9. 34 p. U.S. DEPT. COMMERCE. 1961-69. Climatological dataUtah Vols. 63-71.

Guidelines for Grazing Sheep on Rangelands Used by Big Game in Winter

A big game winter range in nor-then Utah was grazed with domestic sheep to ascertain what seasons and intensity of use would maximize utilization of herbs and minimize utilization of shrubs which provide the majority of forage for big game in winter, thus minimizing forage competition between big game and sheep. In late spring and early summer sheep ate mostly herbs. The light utilization of shrubs resulted in little or no reduction in forage production by shrubs at the end of the growing season. After midJuly, sheep heavily utilized bitterbrush (Purshiu triamtata), the most desirable and abundant shrub for big game in this area. Grazing after mid-July reduced the volume of bitterbrush forage available for big game proportionately to the percentage utilization observed. There was no evidence that subsequent annual productivity of established plants was impaired by any of the grazing systems imposed.

Herbicide Treatment of Browse on a Big-Game Winter Range in Northern Idaho

2,4-D; 2,4,5-T, and a mixture of these two chemicals were tested for effectiveness in lowering the live crown and increasing the basal sprouting of browse grown beyond the reach of elk and deer. Concentrations of 3/, 11/2, and 3 lb acid equivalent per acre were applied by helicopter in late June. Date of spraying was studied separately. The mixture at 3 lb per acre was most effective in killing aerial crowns. Rocky Mountain maple (Acer glabrum) was relatively resistant to these sprays; Scouler willow (Salix scouleriana), Saskatoon serviceberry (Amelanchier alnifolia), creambush rockspirea (Holodiscus discolor), and bitter cherry (Prunus emarginata) were moderately sensitive; redstem ceanothus (Ceanothus sanguineus), and Lewis mockorange (Philadelphus lewivsi) were very sensitive. Willow sprouted prolifically; rockspirea and maple sprouted moderately; ceanothus and mockorange sprouted poorly. Species differed considerably in reaction to date of spraying. Early summer and late summer spraying were usually more effective than midsummer spraying; however, the study revealed no seasonal pattern that could be used as a general guide for spraying to achieve optimum effectiveness in browse rehabilitation. Limitations governing present use of these herbicides for browse improvement in northern Idaho should be noted carefully. Only cautious use of spraying is proposed. Much of northern Idaho's winter range for elk and deer is unique in two respects. First, it consists of seral shrub fields that have resulted from wildfires or logging in coniferous timber stands; the natural succession is toward closed conifer stands that produce little palatable browse. Second, many browse species grow tall beyond the reach of elk and deer. Important among these are willow, serviceberry, maple, and bitter cherry. Once the shrub crowns extend above the animal's reach, the shrubs continue to occupy the site fully but produce very little available browse. This condition prevails especially on elk winter ranges along the Lochsa and Selway Rivers. Reversion of much former winter range to conifers increases the need for maintaining maximum browse production on areas designated specifically as big-game winter range. In part, this means restoring to usable production all plants too tall for the animals' use. Cutting, burning, and using herbicides have all been considered as possible methods to kill back old growth and stimulate sprouting of tall-growing browse species. Cutting appears effective, but it requires using manual labor on steep slopes; this is expensive-approximately $107 per acre in 1962. (Cost of $87 in 1950, reported in files of Clearwater National Forest, is adjusted here to 1962 level using U. S. Bureau of Labor Statistics index of wages for lumber and wood products.) Burning over such steep slopes is risky because of the soil erosion potential and problems of fire control. Aerial application of a suitable herbicide would avoid the objectionable features of the other two methods. Herbicides are being used extensively elsewhere for controlling brush. Usually the objective is complete kill rather than only top kill intended to induce basal sprouting. Until recently, the effects of herbicides on northern Idaho browse species have received little attention. DeJarnette et al. (Preliminary report of spraying ribes and brush with 2,4,5-T by helicopter in the western white pine region. U. S. Forest Service, Region 1, Serial 144. 14pp. (Processed.) 1949) achieved at least 75 percent top kill of Salix sp., Amelanchier florida, Acer glabrum, and Ceanothus velu-

An Evaluation of Big Game Winter Range in Southwestern Alberta

After one growing season of protection there was very little difference in herbage production and composition inside and outside the exclosure. However, by the end of the fourth growing season herbage production inside the exclosure had increased to 2,775 pounds per acre, an increase of nearly 600 percent in only 4 years. Baldgrass, (Sporobolus neglectus Nash.) which had been the dominant species, had decreased to only 8 percent of the total production while little bluestem had increased from almost nothing to 56 percent. Big bluestem (Andropogon gerardi Vitman) and Indiangrass, (Sorghastrum nutans (L) Nash.) had increased from a trace to 17 percent and 11 percent, respectively. In 1956, as now, the glades outside the exclosures were producing about 400 pounds of ovendry herbage per acre, mostly the less desirable baldgrass and black-eyed susan (Rudbeckia hirta L.) with a scattering of the more desirable little bluestem (Andropogon scoparius Michx.) and Indiangrass (Table 1). Herbage production in the nearby Lizzard Pen Exclosure probably reached a peak 5 or 6 years after fencing, but production decreased about 25 percent over the years. Such a decrease is typical of the reaction of any grassland area where the old herbage is not removed periodically. After 21 years of complete protection, herbage production has stabilized, because of continued complete protection, at about 2,150 pounds per acre, 23 percent less than production in the Caney Tower Exclosure. The greatest difference was in production of little and big bluestem, but the significance of this difference was offset to some extent by greater Indiangrass production in the Lizzard Pen Exclosure. Many of southwest Missouri's glade ranges in poor condition could contribute more to the forage resource of the region if they were given 3 or 4 years of complete protection from grazing and moderately stocked thereafter. Complete recovery would probably not be obtained after only 3 or 4 years, but the range should continue to improve under moderate grazing.

Utilization of Winter Browse on Wilderness Big Game Range

During the late 1920's and early 1930's, signs of destructive use of big game winter range began to appear along the canyon of the Selway River of northern Idaho. The once-large mule deer herds of that isolated region were beginning to dwindle, and the formerly small elk herds had built up to numbers previously unrecorded. In the ensuing years, interested agencies carried on several studies of this problem. The most recent is Pittman-Robertson Project W-97-R of the Idaho Department of Fish and Game, the Selway Wilderness Game Study, which was begun in the fall of 1950, in cooperation with the United States Forest Service. In June of 1951, the Idaho Cooperative Wildlife Research Unit began active participation when the writer undertook some of the winter range studies. The objectives were investigations of composition of cover, stage of succession, current use, and availability of browse during winter. This paper is a part of a master's thesis entitled: A preliminary study of the