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  Emerging Issues in Rangeland Ecohydrology: Vegetation Change and the Water Cycle

  Wilcox, Bradford P.; Thurow, Thomas L. (Society for Range Management, 2006-03-01)

  Rangelands have undergone—and continue to undergo—rapid change in response to changing land use and climate. A research priority in the emerging science of ecohydrology is an improved understanding of the implications of vegetation change for the water cycle. This paper describes some of the interactions between vegetation and water on rangelands and poses 3 questions that represent high-priority, emerging issues: 1) How do changes in woody plants affect water yield? 2) What are the ecohydrological consequences of invasion by exotic plants? 3) What ecohydrological feedbacks play a role in rangeland degradation processes? To effectively address these questions, we must expand our knowledge of hydrological connectivity and how it changes with scale, accurately identify ‘‘hydrologically sensitive’’ areas on the landscape, carry out detailed studies to learn where plants are accessing water, and investigate feedback loops between vegetation and the water cycle. 
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  Successful Adaptive Management—The Integration of Research and Management

  Morghan, Kimberly J.; Sheley, Roger L.; Svejcar, Tony J. (Society for Range Management, 2006-03-01)

  Adaptive management is a way for managers to do their jobs in the face of uncertainty and learn by doing. Managers gain greater knowledge of their systems by testing different strategies during the management process. The term ‘‘adaptive management’’ is used often, but there is confusion about exactly what adaptive management is, and managers are hard-pressed to find any clear guidelines for implementing it. As a result, they can find the process of moving from the concept of adaptive management to the actual practice intimidating; they need a clear understanding of adaptive management before they can begin to use it. Luckily, adaptive management is not as complicated as the literature sometimes makes it appear. The process of adaptive management involves formulating questions, selecting alternative techniques to test these questions, and testing these techniques on the landscape. Care is taken to measure those system responses that best tell whether the system is moving toward site objectives, and results are fed back into the decision process. We argue that there are 2 strategies that can be used to improve the success of adaptive management. The first is to start with a simple adaptive management plan and then add complexity over time. The second is to include researchers in all stages of the process to benefit from their expertise in ecology, experimental design, and data analysis. Although adaptive management takes time, rewards include increased understanding of the system, a management program that is scientifically valid, and a management strategy tailored to a particular site. In this paper we briefly explain adaptive management and then offer a step-by-step process for developing and implementing adaptive management in small reserves or on private lands. We believe increased understanding of adaptive management will lead to its widespread use and will ensure that more people benefit from its strengths. 
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  Seasonal Variation in Resistance of Aspen Stems to Shearing Force

  Dockrill, Craig W. M.; Bailey, Arthur W.; Blenis, Peter V.; King, Jane R. (Society for Range Management, 2006-03-01)

  Seasonal changes in aspen (Populus tremuloides Michx.) resistance to shearing force were described to determine their apparent contribution to seasonal changes in cattle utilization. Shearing resistance of current-year, 1-year-old, and 2-year-old stem-age classes were measured from late spring to early fall. For all stem-age classes, resistance to shearing force increased with time, partially due to increasing stem diameter. Depending on stem-age class, resistance to shearing force increased by 200%-2000% between the first and last measurements of a given year. Increased resistance of aspen stems to shearing force in late summer may reduce their selection by cattle. Grazing management that defers cattle entry until midsummer could reduce damage to re-generating aspen associated with cattle foraging in cut blocks.
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  Effect of Standing Litter on Rough Fescue Utilization by Cattle

  Moisey, Darlene M.; Willms, Walter D.; Bork, Edward W. (Society for Range Management, 2006-03-01)

  Seasonal changes in aspen (Populus tremuloides Michx.) resistance to shearing force were described to determine their apparent contribution to seasonal changes in cattle utilization. Shearing resistance of current-year, 1-year-old, and 2-year-old stem-age classes were measured from late spring to early fall. For all stem-age classes, resistance to shearing force increased with time, partially due to increasing stem diameter. Depending on stem-age class, resistance to shearing force increased by 200%-2000% between the first and last measurements of a given year. Increased resistance of aspen stems to shearing force in late summer may reduce their selection by cattle. Grazing management that defers cattle entry until midsummer could reduce damage to re- generating aspen associated with cattle foraging in cut blocks. 
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  Cattle Consumption of Velvet Lupine (Lupinus leucophyllus) in the Channel Scablands of Eastern Washington

  Ralphs, Michael H.; Panter, Kip E.; Gay, Clive; Motteram, Ernie; Lee, Stephan T. (Society for Range Management, 2006-03-01)

  Certain lupines (Lupinus spp.) contain alkaloids that cause contracture-type skeletal birth defects and cleft palate (‘‘crooked calf syndrome’’) when consumed by cows during the 40th to 70th day of gestation. The objective of this study was to determine when cattle graze velvet lupine (Lupinus leucophyllus Dougl.) during its phenological development, and whether this period overlaps the critical period of gestation. Grazing studies were conducted in 2001, 2002, and 2003 in the same 100 ha pasture in eastern Washington. A second objective was addressed in 2001 to determine if cows with crooked calves consumed more lupine than cows with normal calves. Five mature Hereford cows with crooked calves at their side and 6 mature Hereford cows with normal calves grazed together for the summer. There was no difference (P = 0.17) in the amount of lupine consumed between groups, and all cows consumed some lupine. In 2002, 10 3-year-old Hereford cows with normal calves were used, and in 2003, 8 of the same cows from the 2002 study with normal calves were used. In all 3 years, cows started consuming lupine in July and August after annual grasses dried and annual forbs matured. Lupine is a deep-rooted perennial that remained green and succulent longer into the summer than the associated forages. Concentration of the teratogenic alkaloid anagyrine declined as lupine seeds shattered in late June and early July. Lupine consumption occurred during the critical period of gestation in 2 of the 3 years, but no crooked calves were produced. Apparently, the cows did not ingest sufficient amounts of anagyrine over the susceptible period of time to produce crooked calves. The management recommendation for this site is to restrict access to lupine during July when cattle begin to graze lupine and anagyrine levels may still be relatively high. Once the seeds shatter, toxicity greatly declines. 
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  Effects of Livestock Grazing on Duck Nesting Habitat in Utah

  West, Ben C.; Messmer, Terry A. (Society for Range Management, 2006-03-01)

  Periodic vegetation disturbance is an important yet controversial tool for waterfowl managers. Some have reported livestock grazing removes residual vegetation and thus is detrimental to nesting ducks, and others argue that such disturbance is necessary to maintain grassland health. We evaluated the impact of winter livestock grazing on duck nesting at Bear River Migratory Bird Refuge, Utah. During winter 1999, 6 experimental plots were grazed by cattle and 6 were ungrazed; in winter 2000, 8 plots were grazed and 8 were ungrazed. All grazing treatments were conducted during 15 November-15 March and averaged a stocking rate of 9.5 animal unit months/ha. During the following spring nesting season, we measured visual obstruction readings (VOR) on grazed and ungrazed sites. Although VOR on ungrazed sites were greater than those on grazed sites, this difference became less important as the nesting season progressed. Winter grazing impacted the nesting habitat of early-nesting ducks such as mallards (Anas platyrhynchos), but not that of late-nesting species such as cinnamon teal (Anas cyanoptera) and gadwall (Anas strepera). When using livestock grazing to manage grasslands, waterfowl managers should consider their management goals, the species composition of breeding duck populations, and environmental conditions. 
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  Do Pasture-Scale Nutritional Patterns Affect Cattle Distribution on Rangelands?

  Ganskopp, Dave; Bohnert, Dave (Society for Range Management, 2006-03-01)

  Heterogeneous distribution of ungulates about the landscape can be a particularly vexing problem for resource managers. Although livestock preferences for leaves over stems among plants and patches of herbage are well documented, effects of senescent for- age (herbage supporting both green and cured materials) on cattle distribution and nutrition at pasture scales have not been investigated. Our primary objective was to determine the proportions of time cattle spent foraging within senescent and con- ditioned sectors (areas supporting only current season’s herbage) of pastures. Other endeavors included the following: comparing velocities of foraging cattle in conditioned and senescent sectors, determining diet quality of cattle confined to conditioned and senescent treatments, and quantifying levels of forage utilization by cattle in conditioned and senescent treatments. Global positioning system collars were used to track cattle movement and activity in treated crested wheatgrass (Agropyron desertorum [Fisher ex Link] Schultes) pastures. Over a 7-day trial, cattle were found in senescent and conditioned areas 41% and 59% of the time, respectively. When cattle were grazing, 32% of observations were in senescent sectors and 68% were in conditioned areas. With a decline in standing crop in the conditioned treatment, cattle switched to senescent herbage (73% of observations) on day 7. Standing crop was reduced by 13% to 40% in conditioned sectors and increased by 10% in senescent areas. Despite dispa- rities in the crude protein of standing crops in senescent (x= 6.5%) and conditioned (x= 11.3%) treatments, cattle confined to treatment harvested diets of similar quality (x= 13.6% CP) at turn-out. Cattle walked farther when making transitions between treatments, and walked farther each day as the trial progressed. A preference of foraging cattle for portions of pastures grazed (con- ditioned areas) during the previous growing season suggests that utilization patterns established by livestock are self-sustaining. 
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  The Accuracy of Ground-Cover Measurements

  Booth, D. T.; Cox, S. E.; Meikle, T. W.; Fitzgerald, C. (Society for Range Management, 2006-03-01)

  Ground cover is a key indicator of rangeland condition and influences rangeland management decisions, yet there have been few advances in ground-cover measurement methods. The advent of digital photography and automated image processing promise a revolution in the way ground cover is measured. To assess the potential for automation we compared conventional and automated methods for measuring ground cover against known artificial populations. The known populations were created from 20 nadir images of a Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle Young) vegetation type acquired with a 5-megapixel Olympus E20 digital single lens reflex camera mounted on an aluminum camera frame at 2 m above ground level. The images were converted to color, 2-dimensional images that no longer represented real-world conditions but had known cover values and conserved a simplified form of the pattern and spatial context of the plant community. These images were then printed at 1:1 scale to a 1 X 1-m poster. Posters were evaluated for color cover under laboratory conditions using the conventional techniques of steel-point frame, laser-point frame, line-point intercept, ocular estimation, and line intercept. Photographs of the posters were measured for color cover using standard and custom-created algorithms within the VegMeasure image analysis framework, and using the Digital Grid Overlay method. Results indicate that conventional techniques had significantly greater correlation (92% agreement of measured to known) than measurements from the algorithms used in the VegMeasure analysis (70%). The critical factor influencing accuracy of point-sampling methods was the area of the contact point for the given method. These findings provide an important measure of relative accuracy among methods for land managers and for researchers seeking to improve rangeland monitoring methods. 
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  Herbaceous Restoration of Juniper Dominated Grasslands With Chaining and Fire

  Ansley, R. J.; Wiedemanm, H. T.; Castellano, M. J.; Slosser, J. E. (Society for Range Management, 2006-03-01)

  Juniper (Juniperus spp.) encroachment in grasslands usually progresses toward a stable woody state of mature trees that requires a significant disturbance to shift succession in another direction. Fire alone is often inadequate to shift succession in dense stands of mature juniper and must be preceded by a mechanical treatment such as chaining to reduce juniper competition and increase herbaceous growth that fuels a subsequent fire. However, little long-term data are available that measure combined effects of mechanical and fire treatments on restoration of juniper-dominated grasslands. Here, on a degraded (40% bare ground) north Texas site dominated by redberry juniper (Juniperus pinchotii Sudw), we quantify long-term herbaceous responses to mechanical chaining followed by fire. Two types of chaining, ground-level and elevated, were evaluated and all chained plots were burned 4 years after chaining. Herbaceous and woody responses were measured for several years after both chaining and fire treatments and compared to untreated controls. At study termination, both of the chaining + fire treatments reduced juniper cover from 32% to < 6%, but mortality was < 10%, because most plants basal-sprouted. Total grass production did not increase in chained treatments over the untreated until 3 growing seasons after chaining. Grass production declined the first growing season following the fire treatment, but increased in treated plots to 3 times the untreated the second and third year postfire. Total grass cover in treated plots did not increase over the untreated until the second year after the fire treatment. There was no difference in juniper or herbaceous responses between the 2 chain types. Results suggest increases in herbaceous production from chaining alone were due to increased growth of existing vegetation patches whereas the fire treatment appeared to stimulate herbaceous recruitment into bare soil areas. 
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  Postfire Vegetation Dynamics in Three Rangelands of Northeastern Patagonia, Argentina

  Rastagno, César M.; Defossé, Guillermo E.; del Valle, Héctor F. (Society for Range Management, 2006-03-01)

  In many rangeland ecosystems, the role of fire on vegetation dynamics has been the object of detailed studies. In Argentina, and especially in Patagonia, the knowledge of how fire changes vegetation is scarce. In 3 areas affected by wildfires on different dates (in 1988, 1994, and 1998), we determined the structure of the vegetation (plant cover, density, and biomass) and compared it with that of nearby unburned areas. Based upon these data, we present a qualitative state-and-transition model of this rangeland. For the sites burned in 1988 and 1994, aerial biomass, density, and cover of perennial grasses were significantly greater (P0.05) for burned than for unburned areas. For the site burned in 1998, although there were no significant differences in perennial grass biomass and cover, density was significantly greater compared to the unburned area. Total shrubcover was significantly lower (P0.05) in burned than in the unburned areas, attaining 49.7%, 15.0%, and 5.5% of that of the unburned areas for the sites burned in 1988, 1994, and 1998, respectively. Similar to cover, density for most shrubby species was significantly greater in the unburned than in the burned areas for the 3 sites. Grazing and fires of different intensities, combined with variable rainfall, makes the prediction of postfire vegetation changes difficult. However, it can be generalized that fire changed the vegetation from shrub-dominated steppes, a persistent state in northeastern Patagonia, into a grass-dominated transient state. This change has persisted for more than 10 years after a fire event. From the perspective of sheep raising, the significant postfire increase in perennial grass biomass represents a substantial improvement in the condition of these rangelands. However, repeated fires would be necessary to control the sprouting shrubs and maintain the grass-dominated state.
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  Woody Plant Community in the Cross Timbers Over Two Decades of Brush Treatments

  Engle, David M.; Bodine, Timothy N.; Stritzke, J. F. (Society for Range Management, 2006-03-01)

  The closed overstory of fire-adapted forests throughout the world precludes surface fires of sufficient intensity to open the overstory. The cross timbers, an upland oak forest that spans an area from Texas to Missouri, developed with frequent fire, but removal of fire since European settlement has increased canopy cover of dominant overstory trees. To assess response of woody plant species cover and plant community compositional trajectories to brush treatments that included herbicides and fire in the cross timbers, we analyzed a 20-year data set (1982-2001) from untreated pastures, pastures treated with tebuthiuron or triclopyr in 1983, and pastures treated with tebuthiuron or triclopyr in 1983 and burned periodically thereafter (tebuthiuron + fire and triclopyr + fire). We used analysis of variance to determine change in overstory canopy cover and understory canopy cover in response to experimental treatment, and we used detrended correspondence analysis to assess trajectories of species composition over time. Overstory canopy cover was reduced from more than 100% to less than 20% following initial herbicide application, but canopy cover increased subsequently to over 60% as herbicide-resistant woody species increased in all but the tebuthiuron + fire treatment. The most striking change in overstory occurred in the tebuthiuron + fire pastures, which contained almost 20% cover of sumac (Rhus spp.) by 1994, and in the tebuthiuron pastures, which contained > 40% cover of eastern redcedar (Juniperus virginiana L.) by 1994. Tebuthiuron, both with and without fire as a follow-up, influenced composition of the overstory more than did triclopyr. Application of tebuthiuron appears to be a long-term unidirectional disturbance in the cross timbers. Composition also remained distinct from pretreatment condition in triclopyr-treated pastures after almost 20 years of postherbicide succession. In contrast, the understory woody plant community was quite resilient to both herbicides. 
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  Stocking Rate and Weather Impacts on Sand Sagebrush and Grasses: A 20-Year Record

  Gillen, Robert L.; Sims, Phillip L. (Society for Range Management, 2006-03-01)

  Understanding how stocking rate or grazing intensity affects the abundance of common plant species is fundamental to the sustainable management of rangelands. We had the unique opportunity to determine the impact of stocking rate on shrub canopy cover and grass basal cover in a sand sagebrush (Artemisia filifolia Torr.) grassland of the Southern Plains, United States. Treatments were imposed over a 20-year time span that included an entire precipitation cycle from wet to dry and back to wet conditions. From 1941 until 1951, continuous stocking treatments of 41, 53, and 82 animal-unit-days ha-1 (AUD ha-1) were imposed with straight-bred Hereford steers (initial weight of 213 kg +/- 11 SE) for about 320 days from mid-November to late September of the next year. From 1952 through 1961, the experimental pastures were grazed yearlong by cow-calf pairs at 45, 60, and 87 AUD ha-1. Canopy cover of shrubs and basal cover of grasses were measured by the line-intercept method in 1940, 1942, 1949, 1955, 1958, and 1961. Canopy cover of sand sagebrush was not affected by stocking rate. Individual grass species exhibited positive and negative responses to stocking rate in some years, but no grass species responded to stocking rate in a single direction over the entire length of this long-term study. Stocking rate effects were most obvious under favorable conditions of high precipitation, but these effects were absent during drought. Climatic variability and slope gradient exerted the primary controlling influences on sand sagebrush-grasslands in the Southern Great Plains when stocking rates were within the bounds tested in this study. 
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  Herbaceous Vegetation Responses (1992-2004) to Restoration Treatments in a Ponderosa Pine Forest

  Moore, Margaret M.; Casey, Cheryl A.; Bakker, Jonathan D.; Springer, Judith D.; Fulé, Peter Z.; Covington, Wallace W.; Laughlin, Daniel C. (Society for Range Management, 2006-03-01)

  Ecological restoration treatments are widely applied in southwestern ponderosa pine forests to convert them to an open canopy structure similar to that found at the time of Euro-American settlement. An experiment was initiated in northern Arizona in 1994 to evaluate long-term ecosystem responses to 3 restoration treatments: 1) thinning from below (thinning), 2) thinning from below plus forest floor manipulation with periodic prescribed burning (composite), and 3) an untreated control. Results focus on total herbaceous and functional-group standing crop response to these restoration treatments. Pretreatment data were collected in 1992 and posttreatment responses were measured from 1994 through 2004. Total herbaceous standing crop was significantly higher on the 2 treated areas than on the control over the entire posttreatment period, but did not differ between the thinning and composite treatments. Plant functional groups responded differently to treatments and to drought. In general, the graminoid standing crop responded within several years after the initial treatments and continued to increase through time, until a series of severe droughts reduced standing crop to pretreatment levels. C3 graminoids dominated the standing-crop response, of which bottlebrush squirreltail (Elymus elymoides (Raf.) Swezey ssp. elymoides) was the primary contributor. C4 graminoids had a minimal response to restoration treatments, possibly because they were less abundant before the experiment began or because they were adversely affected by autumn burning. Legumes and forbs exhibited a 4-5 year lag before responding to the thinning and composite treatments. Annual and biennial plants showed a large biomass increase approximately 5 years after implementation of the composite treatment. The restoration goal of optimizing herbaceous standing crop must be weighed against the competing goals of increasing the abundance of specific functional groups, increasing biodiversity or rare plants, and managing invasive plant species. 
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  Elevated Atmospheric CO2 Magnifies Intra-specific Variation in Seedling Growth of Honey Mesquite: An Assessment of Relative Growth Rates

  Polley, Wayne H.; Tischler, Charles R.; Johnson, Hyrum B. (Society for Range Management, 2006-03-01)

  The shrub honey mesquite (Prosopis glandulosa var. glandulosa Torr.) readily encroaches into rangelands in the southwestern United States that vary in annual rainfall by almost a factor of 5 (200 to 1 000 mm). This occurs partly because mesquite seedlings grow rapidly and become uncoupled from competition with established herbaceous vegetation. Species that occupy such a wide precipitation gradient frequently include plants that differ genetically in seedling growth rate. Whether atmospheric carbon dioxide (CO2) enrichment affects seedling biomass uniformly across mesquite genotypes or magnifies the expression of genetic variation in seedling growth remains unresolved. We measured the effects of CO2 enrichment on growth of seedlings derived from 14 adult plants (open-pollinated families), 7 plants each from rangelands located near extremes of the rainfall gradient occupied by the shrub (arid southeastern New Mexico vs. mesic central Texas). Growth was measured over days 10 to 30 following emergence on well-watered seedlings in glasshouses at ambient and elevated CO2 concentrations (391 and 706 lmol mol-1, respectively). Proportional responses of biomass (day 30) to CO2 enrichment varied from 1.03 to 1.74 among families. CO2 enrichment did not consistently favor the largest or fastest-growing families at ambient CO2. Rather, proportional responses of biomass to elevated CO2 were highly correlated across families with the stimulation of relative growth rate (RGR) at elevated CO2. Biomass at ambient CO2 was 19% greater, on average, in families from mesic rangeland than from arid rangeland, but families from extremes of the precipitation gradient did not diverge by seedling size or response to CO2. Selection for greater RGR could augment the mean growth response of mesquite seedlings to CO2. Even in the absence of selection, CO2 enrichment could increase mesquite establishment by enhancing seedling growth and thereby exacerbate the management challenge of minimizing woody encroachment. 
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  Fluxes of CO2 From Grazed and Ungrazed Tallgrass Prairie

  Owensby, Clenton E.; Ham, Jay M.; Auen, Lisa M. (Society for Range Management, 2006-03-01)

  To determine the impact of seasonal steer grazing on annual CO2 fluxes of annually burned native tallgrass prairie, we used relaxed eddy accumulation on adjacent pastures of grazed and ungrazed tallgrass prairie from 1998 to 2001. Fluxes of CO2 were measured almost continuously from immediately following burning through the burn date the following year. Aboveground biomass and leaf area were determined by clipping biweekly during the growing season. Carbon lost because of burning was estimated by clipping immediately prior to burning. Soil CO2 flux was measured biweekly each year using portable chambers. Steers were stocked at twice the normal season-long stocking rate (0.81 ha steer-1) for the first half of the grazing season (– May 1 to July 15) and the area was left ungrazed the remainder of the year. That system of grazing is termed ‘‘intensive-early stocking.’’ During the early growing season, grazing reduced net carbon exchange relative to the reduction in green leaf area, but as the growing season progressed on the grazed area, regrowth produced younger leaves that had an apparent higher photosynthetic efficiency. Despite a substantially greater green leaf area on the ungrazed area, greater positive net carbon flux occurred on the grazed area during the late season. Net CO2 exchange efficiency was greatest when grazing utilization was highest. We conclude that with grazing the reduced ecosystem respiration, the open canopy architecture, and the presence of young, highly photosynthetic leaves are responsible for the increased net carbon exchange efficiency. Both GR and UG tallgrass prairie appeared to be carbon-storage neutral for the 3 years of data collection (1998 ungrazed: – 31 g C m-2, 1998 grazed: –5 g C m-2; 1999 ungrazed: –40 g C m-2, 1999 grazed: –11 g C m-2; 2000 ungrazed: +66 g C m-2, 2000 grazed: 0 g C m-2). 
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  ‘‘Silver Sagebrush Community Associations in Southeastern Alberta, Canada’’: A Response

  Jones, Paul F.; Penniket, Roy; Fent, Livio; Nicholson, Joel; Adams, Barry (Society for Range Management, 2006-01-01)

  Habitat, or resource selection, studies are a keystone discipline in wildlife conservation and management. Historically, resource selection studies were completed at a single scale, usually the site level, because of a lack of landscape-level data. With the advent of faster computers and geographical information systems, analysis at more than one scale is possible and desirable (Manly et al. 2002). For greater sage grouse (Centrocercus urophasianus ) in Alberta, Canada,the analysis of resource selection has been completed at the site scale (Aldridge 2000; Aldridge and Brigham 2002). A lack of spatial data, characterizing ecological sites or habitat types, impeded the analysis of resource selection by sage grouse at the landscape level.
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  ‘‘Silver Sagebrush Community Associations in Southeastern Alberta, Canada.’’ Rangeland Ecology & Management 58:400-405

  Aldridge, Cameron L.; Boyce, Mark S. (Society for Range Management, 2006-01-01)

  Understanding the distribution and abundance of habitat and resources is an important issue in wildlife conservation and will advance understanding of wildlife habitat relationships (Morrison 2001). Jones et al. (2005) developed a vital habitat layer, describing the distribution of silver sagebrush (Artemisia cana Pursh) in southeastern Alberta, Canada, and identifying relationships between sagebrush characteristics and physiographic parameters. This paper adds greatly to our understanding of poorly-studied silver sagebrush communities and as Jones et al. (2005) point out, this is an important first step in developing management plans for sage-grouse (Centrocercus spp.) recovery. This product has recently been used to understand sage-grouse habitat relationships, linking habitat to the viability of the endangered Alberta greater sage-grouse (Centrocercus urophasianus) population (Aldridge 2005). 
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  Response of Two Semiarid Grasslands to a Second Fire Application

  Carleton, White S.; Rosemary, Pendleton L.; Burton, Pendleton K. (Society for Range Management, 2006-01-01)

  Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non-point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil fertility measured by nitrogen-mineralization potentials for the respective cover classes over a 9-year period during which 2 fires occurred. In general, the effects of two drought periods were equal to or greater than the effects of fire on the measured parameters. Following the second fire at the grama grass-dominated site, the number of live junipers was significantly lowered (P < 0.001). Fire consumed grass and shrub cover, which created the potential for greater transport of sediment and loss in soil surface elevation. Soil fertility under shrubs was significantly higher than soil fertility under grasses in both grassland sites before and after the first fire; however, that highly significant pattern was not present after the second fire for about 2 years at both sites. This suggests that the reestablishment of a natural fire frequency would likely dampen the well-documented pattern of greater soil fertility under shrub islands relative to grass islands. Repeat use of prescribed fire may keep shrub cover in check and promote fundamental changes in soil processes within semiarid grasslands, but its value must be weighed against the increased potential for erosion following fire. 
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  Restoration of Quaking Aspen Woodlands Invaded by Western Juniper

  Bates, Jonathan D.; Miller, Richard F.; Davies, Kirk W. (Society for Range Management, 2006-01-01)

  Western juniper (Juniperus occidentalis spp. occidentalis Hook.) woodlands are rapidly replacing lower elevation (< 2 100 m) quaking aspen (Populus tremuloides Michx.) stands throughout the northern Great Basin. Aspen restoration is important because these communities provide critical habitat for many wildlife species and contain a high diversity of understory shrubs and herbaceous species. We studied two juniper removal treatments to restore aspen woodlands. Treatments included cutting one-third of the juniper trees followed by early fall burning (FALL) or early spring burning (SPRING). Selective cutting of juniper was performed to increase cured surface (0-2 m) fuel levels to carry fire through the woodlands. We tested treatment effectiveness at removing juniper from seedlings to mature trees, measured aspen sucker recruitment, and evaluated the response to treatment of shrub and herbaceous cover and diversity. In the FALL treatment, burning eliminated all remaining juniper trees and seedlings, stimulated a 6-fold increase in aspen suckering (10 000 ha-1), but initially resulted in a significant reduction in herbaceous cover. Spring burning removed 80% of the mature juniper trees that remained after cutting. However, 50% of juniper juveniles survived the SPRING treatment, which will permit juniper to redominate these stands in less than 80 years. Aspen suckering in the SPRING increased only 2.5-fold to 5 300 stems ha-1 by the third year after fire. In the SPRING, herbaceous cover increased 330% and the number of species observed doubled by the third year after fire. If the management objective is to eliminate western juniper with minimal cutting and stimulate greater aspen suckering, we recommend that woodlands be burned in the fall. If the objective is to maintain shrub and herbaceous cover and moderately increase aspen suckering, spring burning is recommended. With spring burning it appears follow-up management will be necessary to remove juniper that are missed in initial treatments. 
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  Elk, Mule Deer, and Cattle Foraging Relationships on Foothill and Mountain Rangeland

  Torstenson, Wendy L. F.; Mosley, Jeffrey C.; Brewer, Tracy K.; Tess, Michael W.; Knight, James E. (Society for Range Management, 2006-01-01)

  Foraging niche overlap among Rocky Mountain elk (Cervus elaphus nelsoni), Rocky Mountain mule deer (Odocoileus hemionus hemionus), and cattle (Bos taurus) was studied for 2 years on 37 000 ha of nonforested foothill and mountain habitat in northwestern Wyoming. Microhistological analysis was used to quantify botanical composition of ungulate diets from monthly fecal collections. Feeding habitat use was determined through monthly surveys from fixed-wing aircraft to record nonsolitary animals in nonforested habitat. Kulcyznski’s similarity index was used to calculate dietary and feeding habitat overlap among the 3 ungulates, and these 2 indices were multiplied together to estimate foraging niche overlap. In all seasons, elk and cattle consumed grass-dominated diets (mean = 61% and 81%, respectively), although elk diets were more diverse. Mule deer consumed more forbs and shrubs than either elk or cattle (P < 0.10). Foraging niche overlap was high (45%) between mule deer and elk in spring. Cattle in summer and fall had 60% foraging niche overlap with elk in spring, indicating that, in spring, elk foraged in many of the same places (largely sagebrush grassland) and ate diets similar in botanical composition to what cattle did during summer and fall (principally Festuca idahoensis, Pseudoroegneria spicata, and Achnatherum spp.). Foraging niche overlap also was high (41%-51%) between elk in winter and cattle in summer and fall. Therefore, if competitive or complementary relationships existed between elk and cattle, these interactions most likely occurred on sagebrush grasslands where cattle use in summer-fall was followed by elk use in winter-spring. We recommend that resource managers focus their forage utilization and range trend monitoring in foothill sagebrush grasslands. 

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