• Variation in Pinehill Bluestem, a Southern Ecotype of the Andropogon scoparius Complex

      Grelen, H. E. (Society for Range Management, 1974-07-01)
      Pinehill bluestem is the most common variant of the little bluestem (Andropogon scoparius) complex in pine forests of north and central Louisiana and east Texas. It is also frequent in adjacent portions of Oklahoma and Arkansas. It differs from other inland forms of little bluestem primarily in its unreduced pedicellate spikelets, which are equal in size to the sessile spikelets. Because of vegetative similarity between pinehill bluestem and associated forms of A. scoparius, separation of varieties for purposes of forage management is not recommended.
    • Variation in Timing of Planting Influences Bluebunch Wheatgrass Demography in an Arid System

      Boyd, Chad S.; James, Jeremy J. (Society for Range Management, 2013-03-01)
      Establishing perennial grasses from seed in postdisturbance Wyoming big sagebrush (Artemesia tridentata subsp. wyomingensis Welsh) communities is often unsuccessful, due in part to a lack of knowledge of the seedling ecology of perennial grasses. We examined the influence of planting timing on germination and seedling demography of bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) in the northern Great Basin. In 2008 (year 1) and 2009 (year 2) we planted seeds monthly, September- December, in 1-m2 plots (500 seeds per plot) using a randomized block design with five replications. Germination timing was indexed using seed bags placed adjacent to 1-m2 plots and retrieved at 2-wk intervals in fall and 1 mo intervals in spring. Seedlings were marked in March-June of the year following planting; seedlings alive in July were considered initially established. Planting in September and October had up to 80% germination prior to winter, whereas December plantings germinated mainly in spring and at reduced rates (15-35%). Seeds planted in September and October emerged approximately a month earlier than November-December plantings. The percentage of germinated seeds that emerged was highest for September-October plantings but the percentage of emergent seeds surviving to the end of the first growing season was highest for later plantings. Final seedling density was lowest for November planting in year 1 and highest for September and October planting in year 2. Our data indicate that timing of and performance at critical stages of seedling development were affected by planting month. We suggest that it may be possible to use emerging technologies (e.g., seed coatings or germplasm manipulations) to produce variable chronologies of seedling development with single plantings and allow managers to exploit multiple temporal windows of opportunity for seedling establishment.
    • Variation in Utilization of Big Sagebrush Accessions by Wintering Sheep

      Welch, B. L.; McArthur, E. D.; Rodriguez, R. L. (Society for Range Management, 1987-03-01)
      We observed the effects of accessions of big sagebrush (Artemisia tridentata) on big sagebrush utilization by wintering domestic sheep. The sheep had continuous access to high quality alfalfa hay and were fed 0.28 kg of rolled barley per head per day. Utilization was expressed as a percent of the current year's vegetative growth consumed by the sheep and also as grams of dry matter eaten per stem. Utilization of accessions varied from 0 to 98% over 3 sites and from 0 to 7.112 g of dry matter per stem. The sheep tended to remove significant (60 to 70%) amounts of current growth from the more preferred accessions before removing even small (15%) amounts of less preferred accessions. If this is typical grazing behavior, preferred big sagebrush plants may be lost in areas subject to repeated grazing.
    • Variation in Winter Levels of Crude Protein among Artemisia tridentata Subspecies Grown in a Uniform Garden

      Welch, B. L.; McArthur, E. D. (Society for Range Management, 1979-11-01)
      We discovered that the midwinter crude protein content of Artemisia tridentata is under genetic control. Our study demonstrated that some accessions of A. tridentata, grown under uniform conditions, contained significantly higher levels of crude protein than others. Subspecies tridentata contained significantly higher levels of crude protein than subspecies vaseyana and wyomingensis. However, the accessions that contained the highest levels of crude protein have been reported to be least palatable to mule deer. A superior strain of A. tridentata can be developed by combining the high protein-yielding accessions with accessions that are higher in palatability. The new strain could supply more protein for mule deer on winter ranges.
    • Variation of BLM employee attitudes toward environmental conditions on rangelands

      Richards, R. T.; Huntsinger, L. (Society for Range Management, 1994-09-01)
      Using survey data collected as part of a comprehensive reevaluation of the Vale Rangeland Rehabilitation Project in eastern Oregon, this exploratory study examined variation in attitudes of Bureau of Land Management (BLM) employees toward rangeland environmental conditions. Almost one-half of the BLM employees surveyed believed the loss of streamside vegetation (48%) and streambank erosion (42%) were widespread problems on Vale rangelands. Approximately a quarter of the respondents believed rangeland soil loss (24%) and overgrazing (26%) were problems, while only a tenth believed water pollution (10%) was a problem on many or most areas. A composite scale of these attitude toward environmental conditions on rangelands was developed and assessed. The composite scale was regressed on respondents' regional affiliation, length of service, and ideological attitudes towards government role in natural resource management. In contrast to findings from studies for USFS employees, attitudes toward range environmental conditions were not determined by regional affiliation or length of service (P > 0.05). Rather, BLM employee attitudes toward range environmental conditions were found to vary by the interaction of length of service in the agency and attitude toward government's role in regulating water quality (P < 0.05) and managing livestock grazing (P < 0.01). As length of service increases, core beliefs, professional norms, or client constituencies may not polarize employee attitudes but rather moderate them over time. The accumulation of environmental knowledge may also tend to influence environmental attitudes so that ideological attitudes may have a weaker effect as time passes and expertise expands.
    • Variation of Esophageal Fistula Samples Between Animals and Days on Tropical Grasslands

      Torell, D. T.; Bredon, R. M.; Marshall, B. (Society for Range Management, 1967-09-01)
      Forage collected by esophageal-fistulated cattle varies in chemical composition between days and animals. The number of samples needed for a given degree of accuracy was determined. Silica content of fistula steer feces was significantly different from feces from the non-fistulated steer. There were no significant differences in crude protein, crude fiber, and ether extract.
    • Variation of Monoterpenoid Content among Subspecies and Accessions of Artemisia tridentata Grown in a Uniform Garden

      Welch, B. L.; McArthur, E. D. (Society for Range Management, 1981-09-01)
      We discovered that the midwinter monoterpenoid (volatile or essential oils) content of A. tridentata is under genetic control. We base this conclusion on the results of our study which demonstrated that some accessions of A. tridentata, grown under uniform conditions, contained significantly higher levels of monoterpenoids than others. The relationship between monoterpenoids, digestion, and palatability has not yet been conclusively demonstrated. If monoterpenoids interfere with digestion or have a negative impact on palatability, breeding and selection schemes can be developed to capitalize on the significant variation that exists among accessions of A. tridentata. Superior strains of A. tridentata could then be developed for use on mule deer winter ranges.
    • Variations in nutritional quality and biomass production of semiarid grasslands

      Corona, M. E. P.; de Aldana, B. R. V.; Criado, B. G.; Ciudad, A. G. (Society for Range Management, 1998-09-01)
      The effect of the growing season and topographic zone on biomass production, protein content, cell content (CC), lignin, cellulose, hemicellulose, digestibility (DMD), and mineral element concentrations (P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn) were studied in herbage samples collected from semiarid grasslands in Central Western Spain. Protein and mineral contents decreased as the growing season progressed whereas fibre properties tended to increase. Topographic gradient significantly affected peak biomass production, fibre properties, protein and mineral contents. Stepwise multiple regression showed that the prediction of biomass production on these areas was related to cellulose, Na, Fe, and Mg contents in the grassland community whereas fibre properties were mainly predicted by Ca, Na, and Cu. Principal component analysis indicated that the temporal evolution (component II) of the organic variables determined pasture quality whereas most of the variation in mineral content was related to the topographical gradient (component I). Some organic and inorganic parameters may cause deficiencies in cattle grazing en the upper and middle zones, mostly at the end of the growing season. The data suggest that information about the temporal and spatial variations of the production and nutritional quality of semiarid grassland is necessary for making correct management.
    • Variations in Physiological Metabolites and Chlorophyll in Sexual Phenotypes of 'Rincon' Fourwing Saltbush

      Tiedemann, A. R.; McArthur, E. D.; Freeman, D. C. (Society for Range Management, 1987-03-01)
      An experiment was conducted to determine if concentrations of chlorophyll and basic metabolites (total organic nitrogen (TN), total phosphorus (TP), and total nonstructural carbohydrates (TNC)) were an indication of the physiological vigor of the 3 sexual phenotypes of fourwing saltbush (Atriplex canescens (Pursh) Nutt.). Our basic hypothesis was that males, females, and plants capable of male and female sex expression (sexually labile) were equally vigorous as was manifested in chlorophyll and metabolite levels. In June, concentrations of chlorophyll a, b, and total chlorophyll in the male phenotype were greater than in either the female or the labile phenotypes. There were no differences among phenotypes for the other dates. Male plants had the highest levels of metabolites (TN, TP, and TNC) when any differences among sexual phenotypes were significant. There were basically no differences in metabolite concentration between the female and labile sexual phenotypes. Results indicate that part of the hypothesis should be rejected-that male, female, and sexually labile plants are equally vigorous based on concentrations of chlorophyll and metabolites. Part of the hypothesis, however, can be accepted-that females and labile plants are comparable in physiological vigor. Levels of all 3 metabolites showed striking trends among sample dates, which indicated that fourwing saltbush has the capability of rebuilding its levels of metabolites in the spring at the physiologically costly time of flowering. This may be related to the photosynthetic efficiency associated with its C-4 photosynthetic pathway.
    • Variations in soil moisture content in a rangeland catchment

      Salve, R.; Allen-Diaz, B. (Society for Range Management, 2001-01-01)
      Soil water studies for California rangelands have focussed on near-surface hydrologic processes, limiting our understanding of spatial-temporal dynamics of the water regime below the root zone. Soil moisture content and potential were monitored for 16 months in 12 locations in an annual grass dominated 20 ha catchment. The data collected were analyzed by ANOVA to determine significant spatial and temporal differences in soil moisture. Further analysis identified variables that influenced the amount of moisture present at a particular subsurface location. It was determined that there were significant differences in the amount of soil moisture present along the vertical profile of each site and between sites. Soil texture, type of vegetation cover, and elevation were the significant variables that influenced the soil moisture status.
    • Vegetal Change in the Absence of Livestock Grazing, Mountain Brush Zone, Utah

      Austin, D. D.; Urness, P. J.; Riggs, R. A. (Society for Range Management, 1986-11-01)
      Canopy cover of vegetation dominated by Gambel oak was determined in 1983 in adjacent canyons characterized by different grazing histories. Results were compared with data collected in 1935, and the methods replicated those used in the earlier study. Vegetal changes since 1935 in Red Butte Canyon where livestock grazing had been excluded since 1905 were small compared with those of Emigration Canyon where heavy grazing continued into the 1930's, but was gradually phased out and discontinued in 1957. Large differences in vegetal cover between the 2 canyons reported in 1935 were mostly eliminated by 1983.
    • Vegetal recovery following wildfire in seeded and unseeded sagebrush steppe

      Ratzlaff, T. D.; Anderson, J. E. (Society for Range Management, 1995-09-01)
      Following an August wildfire, sagebrush (Artemisia L.)/grass benchlands adjacent to Pocatello, Ida., were seeded with a mixture of exotic wheatgrasses and forbs by rangeland drill in November 1987. The effects of seeding on vegetation development in the immediate postfire years were evaluated by comparing plant density, vegetal cover, species composition, species diversity, and standing crop in seeded areas to that in unseeded control plots in 1988 and 1989. We also examined cover of bare ground, litter, and growth form between treatments and between sampling periods. Twenty paired 10-m transects were established in seeded and unseeded areas on each of 3 plots on the burned benches. Plant density, vegetal cover, and species diversity were lower in the seeded areas than in the unseeded areas in 1988 and 1989. Species composition, species richness, and standing crop were similar between treatments. Establishment of seeded species was poor, probably as a result of drought conditions in 1987 and 1988. Most plants observed in seeded and unseeded areas in the spring of 1988 sprouted from established perennials. Even though the first postfire season was a drought year, plant cover in the unseeded areas (18.3%) approached that estimated by a U.S. interagency task force as needed to stabilize soils on that site. In the following year, which had average precipitation, plant cover in both treatments exceeded the task force's estimate of prefire cover. Because the indigenous plant species recovered rapidly, seeding of this burn was unnecessary to establish plant cover and counterproductive in terms of erosion potential. These results serve to emphasize that objective criteria should be established for evaluating the necessity of postfire seeding.
    • Vegetation Analysis of Grazed and Ungrazed Alpine Hairgrass Meadows

      Bonham, C. D. (Society for Range Management, 1972-07-01)
      Alpine hairgrass meadows in Colorado and Wyoming were examined for plant species differences related to sheep grazing history. Nine alpine areas were studied and three of these had not been grazed by domestic sheep for many years. Frequency values for eight plants were found to be useful in determining whether or not hairgrass meadows have been predominantly grazed over the years by domestic sheep. No additional information was obtained by including species cover data for classification purposes.
    • Vegetation and deer response to mechanical shrub clearing and burning

      Rogers, James O.; Fulbright, Timothy E.; Ruthven, Donald C. (Society for Range Management, 2004-01-01)
      Prescribed burning is a recommended maintenance treatment following mechanical treatments of south Texas brushlands, but it is unknown whether it is preferable to additional mechanical treatments to improve habitat for white-tailed deer (Odocoileus virginianus Raf.). We tested the hypotheses that prescribed burning of aerated (top-growth removal of woody plants) plots during late summer would decrease protein-precipitating tannins in browse, increase forb biomass, and increase deer utilization compared to a second aeration. Ten patches of brush, ranging in size from 2.8-8.1 ha, were aerated during spring 1999. In late summer 2000, maintenance treatments were applied; 5 patches were burned and 5 were aerated a second time. Standing crop, nutritional quality, and tannin concentrations (browse only) of deer forages were estimated. Deer tracks crossing bulldozed lanes surrounding each patch were counted to estimate deer use. Standing crop of browse, forbs, grass, succulents, protein-precipitating tannins in browse, and track density did not differ between treatments. Based on deer use and forage biomass response, burning and a second aeration 16-17 months following an initial aeration appear to have similar effects on habitat characteristics and use of cleared patches by white-tailed deer. Because of lower cost, we recommended prescribed burning as a maintenance treatment of aerated shrublands.
    • Vegetation and Litter Changes of a Nebraska Sandhills Prairie Protected from Grazing

      Potvin, M. A.; Harrison, A. T. (Society for Range Management, 1984-01-01)
      End of season components of biomass and litter were measured on a Nebraska Sandhills prairie site to follow vegetation changes during the first 4 years following the cessation of intense livestock grazing. The 1977-1980 mean annual end of season biomass at Arapaho Prairie, a Sandhills prairie site, was 109 g/m2. Summer grazing on Arapaho Prairie was terminated in 1977, and as a result, significant increases in the biomass of the deep-rooted, palatable warm-season (C4) grasses, sand bluestem, little bluestem and switchgrass, have occurred since then. The biomass of the shallowly rooted C4 grama grasses for the 4-year period was significantly correlated with growing season precipitation. Significant decreases in end of season biomass of the cool-season (C3) grasses during the same 4-year period were highly correlated with yearly decreases in May precipitation. Following the removal of grazing, litter increased from 40 to 127 g/m2 from 1977 to 1980. A nonsignificant yearly increase in litter production occurred in the third year after grazing as a steady state of litter production and decomposition was approached.
    • Vegetation and soil response to grazing simulation on riparian meadows

      Clary, W. P. (Society for Range Management, 1995-01-01)
      Riparian areas have not responded consistently to grazing systems, suggesting that more knowledge is needed to explain how different areas respond to specific stresses. Several studies were conducted to determine herbaceous plant response to simulated grazing on riparian areas. One low-elevation redtop (Agrostis stolonifera L.) site in Oregon and 2 high-elevation sedge (Carex spp. L.) sites in Idaho were studied for 3 years. Several combinations of defoliation, compaction, nutrient return, and season of use were examined. The redtop community responded to spring, fall, or spring-fall defoliations by maintaining or increasing the following year's aboveground biomass production. The sedge communities maintained or decreased the following years's biomass production after spring, mid summer, or late summer defoliations. An increase in forbs occurred in 1 sedge community following spring defoliations to 1- or 5-cm residual stubble heights. The most consistent plant response among areas was reduction in height growth and biomass production following compaction treatments. When both defoliation and compaction are considered, it appears that spring, fall, or spring and fall grazing to a 5-cm stubble height on the redtop site would not decrease riparian herbage production. In contrast, when defoliation, compaction, and nutrient return effects are considered in the mountain meadow sedge-dominated communities, grazing once annually during the growing season to a 5-cm stubble height in the spring, or to a 10-cm stubble height in late summer, or at a utilization rate exceeding 30% of the total annual biomass production can reduce herbage production significantly. Results suggest that many of the land management agency riparian guidelines would maintain biomass productivity in these sedge-dominated communities.
    • Vegetation and Soil Responses to Cattle Grazing Systems in the Texas Rolling Plains

      Wood, M. K.; Blackburn, W. H. (Society for Range Management, 1984-07-01)
      The influence of cattle grazing on selected vegetation and soil parameters were evaluated on a clay flat range site with shrub zonal, midgrass, and shortgrass communities in the Rolling Plains near Throckmorton, Texas. Measurements were made on one pasture of each treatment during 1977 following 4 to 20 years of grazing treatments. Heavy, continuous cattle grazing had more area occupied by the shortgrass community than midgrass community. Heavily grazed pastures were generally dominated by the shortgrass community, with midgrasses, depending on the degree of utilization, restricted to the shrub zonal community. Conversely, cattle exclosures had no shortgrass community, and deferred-rotation and moderately stocked continuously grazed systems had much midgrass community with the shortgrass community occupying only 30% of the area, thus increasing range productivity. Vegetation and soil parameters within the high intensity, low frequency and heavily stocked, continuously grazed pastures tended to be similar for the midgrass and shortgrass communities, but the shrub zonal community was generally different. Vegetation and soil parameters in the midgrass community of the moderately stocked, continuously grazed treatment were generally similar to shrub zonal and different from shortgrass communities. Vegetation and soil variables in the exclosures and deferred-rotation treatments were generally similar among the midgrass and shrub zonal communities; however, they differed from the shortgrass communities.
    • Vegetation and soil responses to short-duration grazing on fescue grasslands

      Dormaar, Johan F.; Smoliak, Sylvester; Willms, Walter D. (Society for Range Management, 1989-05-01)
      The effects of animal impact on soil chemical and physical properties as well as range condition were measured over a 5-year period to test the hypothesis that animal impact can improve the nutrient and water status of the soil and promote grassland succession. A seventeen-pasture short-duration grazing system was established in 1981 on 972 ha. The pastures were stocked on average with 278 cows with calves from 1982 to 1986, which was about twice to triple the recommended rate of 0.8 AUM/ha. Increased grazing pressure reduced range condition as reflected by a loss of desirable species such as rough fescue (Festuca scabrella Torr.). Soil moisture was always higher in soils of ungrazed exclosures. Soil bulk density increased while hydraulic conductivity decreased with grazing. Litter was not significantly incorporated into the soil with hoof action. Chitin-N, as a measure of fungal biomass, decreased significantly under the increased grazing pressure. The hypothesis that animal impact would improve range condition was rejected since impact, in the manner applied during the study, resulted in retrogression of the grasslands.
    • Vegetation And Soils Of Alkali Sagebrush And Adjacent Big Sagebrush Ranges In North Park, Colorado

      Robertson, D. R.; Nielsen, J. L.; Bare, N. H. (Society for Range Management, 1966-01-01)
      Alkali sagebrush ranges were found to have a shallow, root restricting claypan soil. In contrast, the adjacent big sagebrush plant community occurred on loamy soils where roots penetrated freely. This direct relationship between range sites and soils shows how soil surveys can be used to determine range sites.