• Viewpoint: Trend assessment by similarity—a demonstration

      Ratliff, R. D. (Society for Range Management, 1993-03-01)
      Methodology for assessing trend in range condition is still evolving. This paper demonstrates use of Dice's community similarity coefficient, 2a/(2a + b + c), with communities present at 3 times and a notional community as a goal. Coefficients range from 0 (indicating a complete lack of similarity) to 1 (indicating complete similarity). Similarity is classed as low (0 - 0.25), moderate (0.26 - 0.50), high (0.51 - 0.75), or full (0.76 - 1). Study of time-goal coefficent graphs is suggested for deciding whether trend is up, down, or static. Defining goals and lack of statistical tests are major limitations. The goal concept and use of data standardization are discussed.
    • Utilization of globemallow (Sphaeralcea) taxa by sheep

      Rumbaugh, M. D.; Mayland, H. F.; Pendery, B. M.; Shewmaker, G. E. (Society for Range Management, 1993-03-01)
      Globemallows (Sphaeralcea spp.) are well adapted to semiarid and arid environments. They are potentially useful as the forb component of seeding mixtures for rangeland improvement in the western states. However, the degree of acceptability of globemallow forage to livestock has not been well established. We tested 13 globemallow accessions representing 4 species and compared their utilization by sheep (Ovis aries) with that of crested wheatgrass [Agropyron cristatum (L.) Gaertn. X A. desertorum (Fisch.) Schult.] and alfalfa (Medicago sativa L.) during fall 1988 and 1989, and spring 1990 and 1991. Alfalfa consistently produced more forage per plant than wheatgrass or globemallows, and a greater portion of the alfalfa was eaten than of the other species. Sheep utilized wheatgrass more than globemallows in the fall, but the converse was true during spring pasturing. Over the 4 years, sheep ate similar proportions of wheatgrass and individual globemallows. The percentage of S. coccinea (Pursh) Rydb. forage consumed equaled that of crested wheatgrass or alfalfa in the fall but did not equal the percentage of alfalfa consumed in spring. However, S. coccinea produced much less total forage than the other species evaluated. Pre-grazing plant dry weight, dry matter content, and the occurrence of rust caused by Puccinea sherardiana Korn were negatively associated with globemallow utilization. Over-winter mortality of grazed globemallow exceeded that of ungrazed plants. Crested wheatgrass and alfalfa stands were not reduced by grazing. Globemallows are acceptable, but not highly preferred, forbs which can be seeded in environments where alfalfa and other more desirable species are not adapted.
    • The use of conditional probability functions in range data analysis and simulation

      Lambert, D. K.; Harris, T. R. (Society for Range Management, 1993-03-01)
      Managers and range scientists are interested in the response of such variables as forage production and animal performance to various environmental and management factors. Due to the inability to control many of the factors affecting range systems, production responses should include distributional information in addition to their expected values. Recent developments in the estimation of conditional probability distribution functions provide the range scientist with a practical procedure to more fully characterize variable responses. The conditional probability distribution approach is applied to an analysis of forage production data from the literature. An illustration of the procedure in range decision analysis derives distributional information on animal performance and net return under several different steer stocking levels.
    • The life cycle of the range condition concept

      Joyce, L. A. (Society for Range Management, 1993-03-01)
      Recent concerns about range condition measures are not the first concerns about measuring the health of rangelands. To examine why change has not occurred in this area, this paper explores the historical development of the range condition concept in the context of the life cycle of a scientific theory. Dyksterhuis' contribution and significant impact on the concept of range condition reflects the close tie between an underlying ecological theory of the time, that grazing alters species composition in a predictable manner, and his field method which measured that change as the difference between the relative composition of the current and climax vegetation. The evolution of the range condition concept differs in significant ways from the evolution of scientific theories such as Clements' climax theory. These differences include the lack of an intellectual center for research on range condition and reflect the institutionalization of technology to measure range condition. Success of alternative models for range condition may require an underlying theory linked to a field method to successfully capture the consensus of the range community.
    • The constituent differential method for determining live and dead herbage

      Gillen, R. L.; Tate, K. W. (Society for Range Management, 1993-03-01)
      Determination of live and dead herbage fractions from mixed herbage samples requires hand separation or specialized laboratory procedures. The constituent differential method is designed to determine the relative proportion of live and dead components in a mixture based on the difference in dry matter concentration between the components. Our objective was to evaluate several characteristics of the constituent differential method under field conditions in tallgrass and mixed grass vegetation. Estimation of live standing crop by this method is most sensitive to the dry matter content of the total mixture and the dead component but becomes less sensitive as the difference between these variables increases. Time-of-day was not usually associated with dry matter content of the herbage components if sampling began after the herbage was thoroughly dry to the touch. Suggested sample sizes in large experimental units for estimating dry matter content are 40-50 samples for herbage mixtures, 10 samples for live herbage, and 5 samples for dead herbage. In 4 field trials the average value for percent live herbage determined by hand separation and the constituent differential method differed by 1.6 percentage units, which was nonsignificant P>0.10). The constituent differential method is a relatively rapid and accurate method for determining live and dead herbage fractions.
    • Soil-water and vegetation dynamics through 20 years after big sagebrush control

      Sturges, D. L. (Society for Range Management, 1993-03-01)
      Soil water withdrawal and vegetation characteristics of mountain big sagebrush (Artemisia tridentala ssp. vaseyana Rydb. Beetie) areas sprayed with 2,4-D (2,4-Dichlorophenoxyacetic acid) were measured for 20 years after treatment. Herbaceous productivity more than doubled in the first 3 years after spraying and was still twice as great as untreated vegetation 10 to 17 years after treatment. Sagebrush removal reduced seasonal water depletion 9% to a 1.8-m soil depth, equal to 2.4 cm of water. The entire difference was realized from soil 0.9-1.8 m deep. Depletion from the surface 0.9 m of soil under grass-dominated vegetation slightly exceeded depletion under sagebrush-dominated vegetation. Mathematical relationships were developed that predict the percent reduction in seasonal water depletion in relation to time since sagebrush control for soil depths of 0.0-1.8 m, 0.0-0.9 m, and 0.9-1.8 m. Mountain big sagebrush was a minor vegetation constituent on treated areas 20 years after spraying. Sagebrush density increased from 2,100 to 4,400 plant/ha between 10 and 20 years after spraying while herbaceous production ranged between 28 and 52 kg/ha. Both density and canopy cover of sagebrush on untreated areas declined significantly over the study because of the actions of a snowmold fungus.
    • Shortgrass range vegetation and steer growth response to intensive-early stocking

      Olson, K. C.; Brethour, J. R.; Launchbaugh, J. L. (Society for Range Management, 1993-03-01)
      A 9-year grazing trial was conducted to compare shortgrass vegetation and steer responses under intensive-early stocking (IES) at 2 stocking rates to season-long stocking (SLS). The stocking rates were (1) equal to SLS, with twice as many steers used for the first half of the SLS grazing season (2X-IES), and (2) greater than SLS. with 3 times as many steers used for the same period (3X-IES). The hypothesis tested was that SLS and 2X-IES would be similar and sustainable in terms of productivity and vegetation composition, whereas 3X-IES would be different and not sustainable. The 3 treatments were assigned to 6 pastures in a randomized-complete block. Grazing was initiated on or near 1 May each year and continued until about 15 July for IES and about 1 October for SLS. Steers were weighted at initiation of grazing and in mid-July, and SLS steers were weighed in October. Vegetation data were collected in July and October in each pasture from 10 randomly located plots. Species composition of grasses was estimated, and grasses and forbs were clipped separately to determine biomass availability. Steer total gain and average daily gain (ADG) under SLS and 2X-IES were equal (P>0.10) during the early season, but 3X-IES gain and ADG were less (P<0.05). Total-season gain was greater under SLS (P<0.05 than either IES treatment, but total- season ADG was equal to that under 2X-IES. Steer production per ha was equal under SLS and 2X-IES, but greater under 3X-IES (P<0.05). Western wheatgrass [Pascopyrum smithii (Rydb.) Löve] and buffalograss (Buchloe dactyloides (Nutt.) Engelm.) composition did not change over time under SLS and 2X-IES, but decreased and increased, respectively, under 3X-IES (P<0.05). Blue grama (Bouteloua gracilis (HBK.) Lag. ex Steud.) and annual grasses displayed initial composition differences (P<0.10) among grazing treatments, but not differential composition shifts over time (P>0.10). Grass and total biomass availability were reduced (P<0.10) over time by 3X-IES. The hypothesis was supported: SLS and 2X-IES were equal in terms of both livestock performance and vegetation responses, but livestock performance and biomass availability were reduced and vegetation composition changed under 3X-IES. Thus, 3X-IES was not sustainable. While SLS and 2X-IES appear biologically equal, using them simultaneously on separate land areas may reduce market variability risk by marketing twice per year.
    • Seasonal height-weight dynamics of western wheatgrass

      Mitchell, J. E.; Elderkin, R.; Lewis, J. K. (Society for Range Management, 1993-03-01)
      Vertical biomass distributions for western wheatgrass (Agropyron smithii Rydb.) from 3 locations in western South Dakota were evaluated to determine effects of location, date, topographic position, past grazing history (vigor), and phenological development. A linear, quadratic regression was used for model development and testing, and analysis was by general linear hypothesis testing. All factors except topographic position were significant; however, only phenological development was useful in a general model for estimating utilization from the percentage of height remaining. This factor was best expressed in 3 leaf-classes of 2-4, 5-6, and 7-10 leaves per tiller. Thus, height-weight relationships can be improved as a biomass predictor if separate regressions are used for these 3 phenological classes.
    • President’s Address: Expanding Partnerships and Continuing Successes

      Artz, J. L. (Society for Range Management, 1993-03-01)
    • Multiple use management of California's hardwood rangelands

      Standiford, R. B.; Howitt, R. E. (Society for Range Management, 1993-03-01)
      The importance of evaluating multiple resource values on rangelands is demonstrated in this study of California's 3.0 million hectares of oak-covered (Quercus spp.) hardwood rangelands. Production functions are derived for oak tree growth on rangelands for stands with at least 50% of the total tree cover in blue oak (Quercus douglasii Hook. & Arn.) based on oak volume per acre and site index. Forage production is estimated based on oak cover, weather variables, growing period, and site factors from data reported in the literature. Hunting revenue and cost functions are derived from a survey of commercial hunting clubs, and are based on oak cover, hunter success variables, hunter demographics, advertising, livestock density, and club size. The interrelationship of these resource values is shown in output from an optimal control model that incorporates these production functions. Oak trees are gradually cleared for situations where cattle are the only economic product, whereas a residual tree canopy is maintained for cases where firewood and hunting enterprises are considered. In addition, cattle stocking is higher and net profitability is lower for the cattle only management scenario when compared with a multiple use management scenario. The development of these multiple use production functions allows the full range of resource management options to be considered.
    • Mesquite control increases grass density and reduces soil loss in southern Arizona

      Martin, S. C.; Morton, H. L. (Society for Range Management, 1993-03-01)
      In 1974 we selected 8 pairs of gully headcuts on the Santa Rita Experimental Range. Mesquite (Prosopis velutina Woot.) on the watershed of 1 headcut of each pair was killed with diesel oil. Densities of perennial grasses and shrubs, shrub cover, surface erosion, headcut advance, and gully depth were recorded at 3-year intervals, 1974-1986. Four of the watershed pairs were in pastures grazed yearlong: 4 were in Santa Rita rotations. Each grazing schedule included 2 watershed pairs that were about 200 m higher in elevation than the other 2. In 1974, before mesquite was killed, perennial grass densities were low with little difference between assigned conditions. By 1977 perennial grass density was greater where mesquite was killed than on untreated watersheds and was greater at upper elevations. Lehmann lovegrass (Eragrostis Lehmanniana Nees.) made up almost all of the grass density increase at the upper elevation. Native perennial grasses, which were largely replaced by Lehmann lovegrass at the upper elevation, accounted for almost all of the gain at the lower elevation. Lower density (P less than or equal to 0.05) on low elevation rotation grazed watersheds in 1986 was the result of summer drouth in 1985 and 1986 that coincided with March-October grazing in 1986. Soil loss (mm) during each 3-year period was lower at headcut-soil surface grids where mesquite was dead. Advances in headcuts and changes in gully depth showed similar trends. On the 4 pairs of watersheds that were equipped to measure runoff, there was more total runoff per millimeter of rainfall where mesquite was alive than where mesquite was killed.
    • Influence of improvement practices on big blue-stem and indiangrass seed production in tallgrass prairies

      Masters, R. A.; Mitchell, R. B.; Vogel, K. P.; Waller, S. S. (Society for Range Management, 1993-03-01)
      Tallgrass prairies provide a valuable source of diverse native plant germplasm. Seed harvested from native prairies can be used to revegetate highly erodible or marginal cropland and degraded rangeland if adequate quantities of seed can be produced. The effect of spring burning, fertilization, and atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] on big bluestem (Andropogon gerardii Vitman var. gerardii Vitman) and indiangrass [Sorghastrum nutans (L.) Nash] reproductive stem density and seed production was determined in 9 tallgrass prairie environments (each year by site was considered a unique environment). Studies were conducted at tallgrass prairies near Bloomfield, Lincoln, and Virginia Nebr., from 1987 through 1990. Atrazine was applied at rates of 0 and 2.2 kg a.iha-1 in mid-spring. Fertilizer rates applied in late spring were 0 and 110-0 kg N-P ha-1 at Lincoln in 1987, 0 and 110-22 kg N-P ha-1 at Bloomfield in 1987 and all sites in 1988, and 0 and 67-22 N-P kg ha-1 at all sites in 1989 and 1990. Improvement practices increased stem density of big bluestem in 5 environments and indiangrass in 4 environments. Number of germinable seed produced by the grasses was influenced by treatment only in 1987 and 1990 when precipitation amounts were above or near the long-term average. In 1987, atrazine increased indiangrass germinable seed number from 202 to 481 seed m-2 at Bloomfield. At Lincoln in 1987, the combined effects of fire, fertilizer, and atrazine increased the number of germinable indiangrass seed to 2,517 seed m-2 as compared to 331 seed m-2 produced on areas that had not been treated. In 1990, burning in mid-May increased big bluestem seed number from 52 to 125 germinable seed m-2 at Virginia, and fertilizer increased big bluestem seed number from 333 to 724 seed m-2 at Lincoln. The tallgrasses did not produce germinable seed in 1988 and 1989, presumably because of drought conditions that persisted both years. Improvement practices evaluated in this study increased native grass seed production when precipitation was adequate. However, no single treatment or combination of treatments reliably or consistently increased the number of seed produced and the absolute amount of seed produced on native prairies was low.
    • Grazing strategies, stocking rates, and frequency and intensity of grazing on western wheatgrass and blue grama

      Hart, R. H.; Clapp, S.; Test, P. S. (Society for Range Management, 1993-03-01)
      Stocking rates and grazing strategies may alter botanical composition of rangeland vegetation by altering frequency and intensity of defoliation of individual plant species. We used long-interval time-lapse photography to study frequency and intensity of defoliation of western wheatgrass (Pascopyrum smithii[Rydb.] A. Love) and blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud.) tillers under continuous season-long and time-controlled short-duration rotation grazing by steers at 2 stocking rates. Frequency, intensity, and variability of defoliation of both grasses were similar under both grazing systems. Western wheatgrass tillers were grazed more frequently under heavy than under moderate stocking, and in 1990 more herbage was removed the second time a tiller was grazed under heavy stocking. Blue grama tillers were grazed more frequently under heavy than under moderate stocking in both years under rotation grazing, but only in 1990 under continuous grazing; more herbage was removed under heavy stocking the second time a tiller was grazed. Under heavy and moderate stocking, respectively, 19% and 36% of western wheatgrass tillers and 42% and 54% of blue grams tillers were ungrazed throughout the grazing season. Few western wheatgrass tillers were grazed more than twice, and few blue grams tillers were grazed more than once. Stocking rates have much greater potential than grazing systems for altering frequency and intensity of defoliation and subsequent changes in botanical composition of range plant communities. Results of grazing studies support this conclusion.
    • Estimation of green herbaceous phytomass from Landsat MSS data in Yellowstone National Park

      Merrill, E. H.; Bramble-Brodahl, M. K.; Marrs, R. W.; Boyce, M. S. (Society for Range Management, 1993-03-01)
      Green herbaceous phytomass was measured in August 1987 in grassland and sagebrush-grassland communities of Yellowstone National Park and related to August 1987 Landsat MSS data. A linear model using MSS band 7 and the ratio of MSS bands 6 to 4 accounted for 63% of the variance in green herbaceous phytomass on ground-truth plots (n = 25). Error in estimates of green herbaceous phytomass was influenced by the relative amount of bare ground and the proportion of green to green plus dead herbaceous vegetation present at a site. The model was used to predict average green herbaceous phytomass in grassland and sagebrush-grassland communities across a 600 km2 portion of ungulate summer range in Yellowstone National Park for 11 years during 1972-1987 using additional Landsat MSS imagery. Green herbaceous phytomass declined seasonally from late July to early September. Annual deviations in green herbaceous phytomass from the 11-year average, corrected for date of satellite overpass, were not significantly related to precipitation or temperatures during the growing season but were related quadratically to December-March precipitation. Below-average green herbaceous phytomass in years of low and high winter precipitation may be related to the effects of snow accumulation and melt on phenological development (green wave) of plants across the summer range. Models based on MSS spectral data can provide useful descriptions of broadscale patterns of plant biomass in Yellowstone National Park but may not suffice when precise estimates are required. Climatic influences on plant phenology may confound the interpretation of results when spectral models are used to compare vegetation yield of forage availability among years.
    • Element concentrations in globemallow herbage

      Rumbaugh, M. D.; Mayland, H. F.; Pendery, B. M.; Shewmaker, G. E. (Society for Range Management, 1993-03-01)
      Globemallows (Sphaeralcea spp.) are native, drought-resistant forbs of interest for inclusion in seed mixtures for semiarid rangeland renovation. Little is known of their nutritional value for ungulates. We measured element concentrations in representative globemallow species and evaluated their adequacy for livestock nutrition. We also correlated forage selection by sheep (Ovis aries) with element concentrations. Alfalfa (Medicago sativa L.), crested wheatgrass [Agropyron cristatum (L.) Gaertn. X A. desertorum (Fisch.) Schult.], and 13 accessions of globemallows [S. coccinea (Pursh) Rydb., S. grossulariifolia (H. & A.) Rydb., S. munroana (Dougl) Spach., and S. parvifolia A. Nels.] were transplanted into replicated grazing trials in southern Idaho. Herbage was sampled and the pastures were grazed by sheep in the fall of 2 years and in the spring of the following 2 years. Concentrations of Ca and Mg in crested wheatgrass were lower than in forbs. Differences between seasons were greater than the differences among globemallow species. Forage selection ratios were positively associated with the N concentration of globemallow leaves and with the Ca:P ratio of globemallow stems but were negatively associated with stem Zn concentrations. Herbage from pastures containing crested wheatgrass with globemallows and/or alfalfa would meet the dietary element requirements of beef cattle (Bos taurus) and sheep.
    • Effects of short duration and high-intensity, low-frequency grazing systems on forage production and composition

      Taylor, C. A.; Brooks, T. D.; Garza, N. E. (Society for Range Management, 1993-03-01)
      Research was conducted at the Sonora Research Station during a 4-year period (1984 to 1988) to measure differences in herbaceous vegetation response between two 7-pasture 1-herd grazing systems. Grazing tactics were short duration (SDG-7 days graze, 42 days rest) and high intensity, low frequency (HILF-14 days graze, 84 days rest). Stocking rate for the 2 treatments was 10.4 ha/auy. Total aboveground net primary production (ANPP) varied significantly among years but not between grazing treatments. Significant, divergent shifts in composition did occur over the 4 years as a function of grazing treatment. Shortgrass production in the SDG pastures increased from 45% of the total ANPP for year 1 to 74% for year 4. Shortgrass ANPP in the HILF pastures comprised 44% of the total herbaceous production for year 1 and 51% for year 4. Midgrass ANPP in SDG pastures comprised 3.8% of the herbaceous production for year 1 and 13.6% for year 4. Midgrass production in the HILF pastures represented 4.7% for year 1 and 33.9% for year 4. Our data indicate the SDG system did not promote secondary succession from shortgrasses to midgrasses as effectively as did the HILF system.
    • Effects of food plots on white-tailed deer in Kisatchie National Forest

      Johnson, M. K.; Dancak, K. D. (Society for Range Management, 1993-03-01)
      An extensive food plot program maintained for 4 years on the National Red Dirt Wildlife Management Preserve of the Kisatchie National Forest, La., failed to produce improvements in southern pine-mixed hardwood forest range sufficient to affect quality of deer (Odocoileus virginianus) harvested by sport hunters. A combination of normal forest management practices plus maintenance of deer densities at relatively low levels was apparently sufficient for maintaining deer in good condition. Other than for public relations, the food plot program was not warranted based on biological effects.
    • Alkaloid levels in a species of low larkspur and their stability in rumen fluid

      Majak, W. (Society for Range Management, 1993-03-01)
      A survey on the levels of the neurotoxic diterpenoid alkaloid methyllycaconitine (MLA) in low larkspur (Delphinium nuttallianum Pritz.) was conducted at rangeland sites in southern British Columbia. Freeze-dried plant samples representing vegetative, flower bud, and bloom stages of growth over 4 growing seasons were analyzed for MLA by high pressure liquid chromatography (HPLC). Differences in MLA concentration were found between sites (P < 0.01) and between stages of growth (P < 0.001) but not between years (P > 0.2). The vegetative stages of growth yielded the highest levels of MLA, approaching 1% of the dry matter at 1 site. On average, the reproductive stages of growth yielded half the amount of MLA as the vegetative stages. Differences in MLA levels between sites could not be attributed to the elevation or the weather during the growing season. It is suggested that topoedaphic effects may have an impact on low larkspur growth and toxicity. Preliminary results are also reported on the stability of MLA in bovine rumen contents. The alkaloid is not readily hydrolyzed in rumen contents and therefore is probably not detoxified by this pathway.