• Increasing utilization efficiency of continuously stocked Old World bluestem pasture

      Teague, W. R.; Dowhower, S. L.; Pinchak, W. E.; Tolleson, D. R.; Hunt, L. J. (Society for Range Management, 1996-11-01)
      The objective of this 2 year study was to identify the optimal height to graze Old World bluestem pasture in the Southern Great Plains under continuous stocking during the growing season. We hypothesized that intensely grazing Old World bluestem pasture would increase utilization efficiency by increasing the proportion of live leaf in the pasture, enhance forage quality and animal performance, and animal performance and root biomass would decline if grazing intensity was beyond an optimal level. Pastures were maintained at 3 levels of standing crop using continuous variable stocking. Stock adjustments were made weekly. A disc meter was used to maintain pasture disc heights of short (35-40 mm), medium (41-45 mm), and tall (46-55 mm) levels. Average standing crops of short, medium, and tall pastures were 1,500, 1,900, and 2,400 kg ha-1, respectively. On the short pasture treatments the proportion of leaf and live stem was higher (P < 0.05) and the proportion of dead stem was less (P < 0.05) than that on the tall pasture treatments. There were no significant differences (P > 0.05) in crude protein of forage between treatments during the vegetative growth phase in spring when forage nitrogen levels were fairly high (> 13%). When the grass began to produce reproductive organs and when forage nitrogen levels were lower (< 1.3%), forage crude protein was greater in the short pastures (P < 0.05). Individual animal performance was greater on the tall than on the short pastures (P < 0.10) over all dates. Individual animal performance was greatest when management maximized the proportion of leaf and live stem while minimizing dead stem. Animal performance per hectare was slightly higher on the short and medium height pastures. Both the short and medium height pastures had approximately 70% the root biomass of the tall pastures (P < 0.01) at the end of the trial. These results indicate that intense continuous variable stocking of Old World bluestem increases the utilization efficiency, but increases animal production per hectare only marginally, and reduces root biomass to an extent that production may not be sustained from year to year.
    • Sahelian rangeland development; a catastrophe?

      Rietkerk, M.; Ketner, P.; Stroosnijder, L.; Prins, H. H. T. (Society for Range Management, 1996-11-01)
      This paper sets out that the dynamics of the Sahelian rangeland vegetation can be interpreted as a cusp catastrophe and that this interpretation offers a promising basis for the description and analysis of this ecosystem. Firstly, an existing scheme of the dynamics of Sahelian herbaceous vegetation is translated into the state-and-transition formulation. Secondly, the application of the cusp catastrophe is explored by studying the behaviour of the Sahelian rangeland ecosystem under changing effective rainfall and grazing intensity, using the transitions from the state-and-transition formulation as vectors along the cusp manifold. This conceptual cusp catastrophe model subsequently results in the identification of hypotheses and the detection of 5 catastrophic properties of this ecosystem (bimodality, inaccessibility, sudden jumps, divergence and hysteresis) that have important management implications. The continuous and the discontinuous processes occurring in the Sahelian rangeland ecosystem can both be captured in a unified conceptual model by applying the cusp catastrophe theory. Testing the hypotheses generated by the conceptual model and searching for additional catastrophic properties, such as divergence of linear response and critical slowing down, is a useful direction for future research.
    • Packhorse grazing behavior and immediate impact on a timberline meadow

      Olson-Rutz, K. M.; Marlow, C. B.; Hansen, K.; Gagnon, L. C.; Rossi, R. J. (Society for Range Management, 1996-11-01)
      Recreational packhorse grazing is one of many uses of high elevation wildland meadows. We quantified the behavior of horses grazing on an upper timberline meadow in southwestern Montana and the immediate impact on the plant community. Horses were picketed on 15-m diameter circles for different durations (0, 4, 8, 18 hours), months (July, August, September), and frequencies (1 month only, all 3 months) over 3 summers. We recorded the amount of time horses spent grazing or resting, horse movement while grazing, plant height, and grazed plant frequency before and after grazing. Grazing was the dominant activity throughout the trial. After an initial 3-4 hour feeding bout, horses continued to graze intermittently. When not grazing, horses rested more than walked. Horses grazed a higher percent of grasses at first (4 hour picket duration) but the percent of fortes grazed increased with increased time on picket. After 18 hours of use, or after repeated use on the same picket circle through the summer, more than 50% of the grasses and 20% of the fortes bad been grazed and tallest plant material was less than 12 cm tall. Recreational packhorse management should include previous training (picket grazing experience), limiting time on specific circles to 8 hours or less, and using picket circles only once each season.
    • Perennial grass establishment in relationship to seeding dates in the northern Great Plains

      Ries, R. E.; Hofmann, L. (Society for Range Management, 1996-11-01)
      A 3-year field study with 5 species and 11 seeding dates per year was conducted to determine which dates resulted in successful stands when directly seeded into wheat stubble at each seeding date at Mandan, N.D. There was considerable range in the monthly highs and lows for many of the environmental parameters collected during this study. Significant seeding date X year interactions occurred due to changes in environmental conditions at each repeated seeding date. This indicates that while certain seeding dates during the year can be expected to provide good grass establishment because of cooler temperatures and more precipitation, failures can also occur at any seeding date when the expected favorable weather conditions fail to materialize. Stands were successful when the stems m-2 were equal to or greater than the stems expected from 11 plants m-2. Successful stands occurred 64, 58, 61, 52, and 45% of the time for smooth bromegrass (Bromus inermis Leyss., 'Lincoln'), western wheatgrass [Agropyron smithii Rydb., 'Rodan'; syn.=Pascopyron smithii (Rydb.) Love], crested wheatgrass [Agropyron desertorum (Filch.) Schult., 'Nordan'], sideoats grama [Bouteloua curtipendula (Michx.) Torr., 'Pierre'], and blue grama (Bouteloua gracilis (El. B. K.) Lag ex Steud., native collection], respectively. The significant seeding date X year interaction indicated established seedling stems m-2 varied greatly at the same seeding date in different years. This interaction explains why individuals favor different seeding dates based on their past experience. Successful seeding dates are summarized, but failures can occur at any specific date in a given year.
    • Recovery of a high elevation plant community after packhorse grazing

      Olson-Rutz, K. M.; Marlow, C. B.; Hansen, K.; Gagnon, L. C.; Rossi, R. J. (Society for Range Management, 1996-11-01)
      We evaluated the impact of packstock grazing on a dry, upper timberline meadow. Horses were picketed on 15 m ropes for different durations, months, and frequencies over 3 summers. Before horse grazing, we estimated vegetal, bare soil, litter, rock, and moss cover, measured grass and forte plant heights, counted grass and forte stems per area, and determined the percent of plants grazed. These measurements were repeated 1 growing season later. More bare ground and less litter and vegetal cover were recorded 1 year following single 8- or 18-hour grazing events. Single grazing events of 4-hour duration had no effect on cover. Decreases in vegetal cover were associated with reduced stem numbers. Eighteen hour picket durations reduced subsequent year production of grass and forte stems. We discuss the difficulties encountered in this study, including estimates of necessary sample sizes, to help in the design of future studies.
    • Mule deer and elk foraging preference for 4 sage-brush taxa

      Wambolt, C. L. (Society for Range Management, 1996-11-01)
      A 10 year study under natural winter conditions at 2 sites tested the hypothesis that mule deer (Odocoileus hemionus hemionus) and elk (Cervus elaphus nelsoni) forage equally on 4 sagebrush (Artemisia L.) taxa. Each year approximately 2,500 available leaders on 244 plants on the Northern Yellowstone Winter Range were examined for browsing. Browsing levels increased with winter severity, reaching 91% of leaders browsed for mountain big sagebrush (A. tridentata ssp. vaseyana [Rydb.] Beetle), the preferred taxon (p< 0.05) that averaged 56.1% at the 2 sites. Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle and Young) was narrowly preferred (38.6%) over basin big sagebrush (A.t. Nutt. ssp. tridentata) (30.3%). Black sagebrush (A. nova Nels.) was least preferred (17.0%). Differences in preference among taxa were smallest during the severest winters when more elk were present thereby increasing total sagebrush utilization. Mule deer diets averaged 52% sagebrush over the study. Many sagebrush plants were damaged and even killed by heavy browsing during the study. Promoting sagebrush productivity should be a management objective on similar winter game ranges.
    • Cattle distribution, habitats, and diets in the Sierra Nevada of California

      Kie, J. G.; Boroski, B. B. (Society for Range Management, 1996-11-01)
      Cattle have been used to control shrubs following timber harvesting in the Sierra Nevada of California, although their effectiveness varies between sites. Although cattle home ranges, habitat use, and diets are known for many forested ecosystems, the coniferous forests of the Sierra Nevada are different because shrubs are the most common understory species, with fewer herbaceous species than elsewhere in the western United States. As a first step in evaluating factors that influence cattle distribution and their potential effectiveness in controlling competing vegetation in the Sierra Nevada, we used radio-telemetry collars on cows to determine their home ranges and habitat use patterns. Mean home range size was 162.80 ha in 1986 and 278.83 ha in 1987. When choosing home ranges, cattle showed the greatest affinity for riparian habitat, followed by clearcuts, second-growth forest, and burned areas. Distances from streams to cattle locations were significantly (P<0.01) less (average=59.3 m in 1986, and (average = 60.1 in 1987) than were distances from streams to random points (average = 130.4 m). Based on microhistological analysis of fecal fragments, cattle diets included seeded grasses and shrubs mostly from upland sites, but forbs primarily from riparian sites. We suggest the need for water and the relative lack of herbaceous forage in the understory of mixed-conifer forests in the Sierra Nevaa resulted in the strong, summer-long preference for riparian habitats. The effectiveness of grazing in controlling competing vegetation following timber harvest may be related to the proximity of the clearcuts to riparian habitats but this specific hypothesis remains to be tested.
    • Buffaloberry [Shepherdia canadensis (L.) Nutt.] fruit production in fire-successional bear feeding sites

      Hamer, D. (Society for Range Management, 1996-11-01)
      Buffaloberry [Shepherdia canadensis (L.) Nutt.] fruits are the usual late-summer food for bears (Ursus spp.) in the Front Ranges of Banff National Park, but little is known about the effect of fire or other factors on fruit production. I assessed the association between fruit production (fruits m-2 of buffaloberry shrub) and environmental factors at 76 plots in Banff National Park and found a negative association with forest canopy cover. Forest canopy cover accounted for 70% of the variation in fruit production. Fruit production also decreased from NNE- to SSW- facing slopes, but this effect was small compared to the decrease associated with increasing forest canopy cover. Forty plots were re-established at or near the original 76 sites the following year. A strong negative association between fruit production and forest canopy cover again occurred, but there was no significant association between fruit production and slope aspect. Fruit production began 5 years after fire in 2 recent burns. In sites burned 23 and 25 years ago, fruit production was comparable to the recorded in older-aged burns, and already was low at one site in the 25-year-old burn where regenerating lodgepole pine (Pinus contorta Dougl.) canopy cover measured 72%. Many sites in older burns, however, have remained forest-free due to xeric site conditions, chinook wind, avalanching, or other factors. These open sites were associated with abundant fruit. Managers must consider the prolonged effects of fire when assessing relation ships among fire, forest canopy cover, and buffaloberry fruit production.
    • Wildlife numbers on excellent and good condition Chihuahuan Desert rangelands: An observation

      Smith, G.; Holechek, J. L.; Cardenas, M. (Society for Range Management, 1996-11-01)
      Information is lacking on the influence of range condition on wildlife populations in the Chihuahuan Desert. Wildlife observations were made along transects on ranges in excellent and good ecological condition in south-central New Mexico (86% and 72% of climax vegetation remaining, respectively). Black grama (Bouteloua eriopoda Torr.) dominated the excellent condition range while the good condition range had a mixture of grasses, forbs, and shrubs. Plant species diversity was greater on the good compared to excellent condition range. Total mammal sightings/km2 during the study period were higher (P<0.05) on the good compared to excellent condition range. Sightings of important game species (scaled quail, mourning doves, pronghorn, desert cottontails) were higher on the good compared to excellent condition range. Lack of diversity in vegetation composition and structure appear to explain the lower wildlife sightings on the excellent condition range. Results from this study indicate that Chihuahuan Desert ranges in good ecological condition (51-75% of the climax vegetation) will better meet the needs of most wildlife species than ranges in climax or near climax range condition. Research shows grazing intensities that remove an average of about 1/3 of current year’s growth of key forage species (black grama) are effective in developing and maintaining range in good ecological condition in the Chihuahuan Desert.
    • Emergence and seedling survival of Lotus tenuis in Festuca arundinacea pastures

      Sevilla, G. H.; Fernández, O. N.; Miñón, D. P.; Montes, L. (Society for Range Management, 1996-11-01)
      Emergence and survival of seedlings of lotus or narrowleaf trefoil (Lotus tenuis Waldst.) were monitored in 4 grazed pastures dominated by tall fescue (Festuca arundinacea Schreb.) for 2 successive years. The objective was to detect patterns and environmental conditions promoting successful seedling establishment of lotus. Emergence followed a seasonal pattern each year, with most emergence occurring towards the end of winter. Seedling emergence occurred mainly in heavily grazed sites which occupied 45 to 90% of each pasture. Seedling emergence was greatest, but seedling survival was poorest in the wettest year. Competition resulting from climatic conditions favoring growth of established pasture plants was detrimental to establishment of lotus seedlings. In contrast, heavily grazed areas provided microsites that enhanced survival of new recruits during the spring growing season. Dense seedling stands emerging on feces were overcrowded and suffered the highest mortality, thus, they contributed little to recruitment of lotus. However, dispersal of lotus was enhanced by the presence of seeds in livestock feces.
    • Feasibility analysis for development of northern China's beef industry and grazing lands

      Simpson, J. R.; Li, O. (Society for Range Management, 1996-11-01)
      China, with one of the largest grassland and pastoral areas of the world, is placing major effort on sustainable modernization of its rangeland livestock industry. One widely discussed structural change involves development of a cattle feedlot industry with grazing lands oriented to a cow/calf system. However, economic analyses of alternatives have not been carried out. The objective in this article is to evaluate the economic feasibility and benefits to sustainability from shifting from fattening cattle on rangelands in Inner Mongolia to fattening in feedlots in the Beijing area. The method is economic budgeting of costs and returns for both systems combined with comparison of protein and energy requirements for each of them. It is concluded that grazing land producers would obtain more net income from selling weaned calves rather than fattened animals. Furthermore although 14,230 Mcal of metabolizable energy and 738 kg of crude protein are required per 4-year old male sold at slaughter weight by grazing land fattening, a feedlot fattened male would require only 5,670 Mcal of energy and 371 kg of protein Additional evaluations of improved cow/calf systems indicate that considerable advances can be made by improving the efficiency of China's cattle industry.
    • Shifts in botanical composition of flatwoods range following fertilization

      Kalmbacher, R.; Martin, F. (Society for Range Management, 1996-11-01)
      Three annual applications of a factorial combination of N (0, 40, 80, 120 kg ha-1), P (0, 25 kg ha-1) and K (0, 100 kg ha-1) were applied to Florida flatwoods range where 45 plant species were initially present. Addition of P and K had no effect (P > 0.05) on indices of plant diversity, density, or above-ground biomass. Both Shannon's (Y = 1.6 - 0.005N, where N is kg ha-1) and Simpson's index (Y = 0.28 + 0.002N) indicated diversity decreased with increasing N because the community was being dominated by goldenrods (Solidago fistulosa and Euthamia minor) and dogfennel (Eupatorium spp.). Density of all fortes increased with increasing N (1990 plants m-2 = 17.4 + 0.4N and 1991 plants m-2 = 35.1 + 1.4N). Density of beaked panicum (Panicum rhizomatum) increased quadratically with increasing N, while density of decumbent carpetgrasses (Axonopus spp.) and low panicums (Dichanthelium spp.) declined linearly. Broomsedge (Andropogon virginicus), wiregrass (Aristida stricta), and bottlebrush 3-awn (A. spiciformis) were eliminated from the site. Above-ground biomass of fortes increased with N (1988 kg ha-1 = 934 + 16.1N and 1990 kg ha-1 = 227 + 60.6N). Grass and grasslike biomass increased linearly as N increased, but N effects were independent of year, which were different (1988 = 1,530 kg ha-1 and 1990 = 2,140 kg ha-1). The plant community at this location became less diverse when the naturally low soil N was increased by 40 kg ha-1 or more. Early successional species replaced later successional species, especially creeping bluestem (Schizachyrium scoparium).
    • Spiny hopsage fruit and seed morphology

      Shaw, N. L.; Hurd, E. G.; Haferkamp, M. R. (Society for Range Management, 1996-11-01)
      Rangeland seedings of spiny hopsage (Grayia spinosa [Hook.] Moq.) may be made with either bracted utricles or seeds. Problems have resulted from inconsistent use of terminology describing these 2 structures and the fact their germination and seedling emergence is not the same with similar environmental conditions and seeding techniques. We examined the flower, fruit, and seed morphology of spiny hopsage microscopically to resolve these discrepancies and provide a basis for discussing the functional roles of bracted utricle and seed components. The spiny hopsage fruit is a utricle consisting of a single disk-shaped seed contained within a thin pericarp. The utricle is enclosed in 2 papery bracteoles. Failure to recognize the obscure pericarp plus inaccurate use of terminology appear responsible for confusion in the literature. The presence and condition of seed and fruit structures can affect seeding requirements and embryo response to environmental conditions. Consequently, accurate identification of all structures associated with the fruit or seed combined with a review of seed biology and seedling establishment literature is essential for designing effective wildland seeding practices.
    • Viewpoint: A theoretical basis for planning woody plant control to maintain species diversity

      Fulbright, T. E. (Society for Range Management, 1996-11-01)
      Range improvement practices have been criticized by scientists and the public because of negative impacts on biodiversity. I present a conceptual model based on ecological theory for designing and planning woody plant control to maintain plant and wildlife species richness and diversity. Broad areas of rangeland have been impacted by overgrazing by livestock and attempted brush control in a manner that has resulted in dense woody plant communities that are resistant to natural disturbances such as fire. State-and-transition models of vegetation dynamics predict these biotic assemblages to be temporally stable and not responsive to successional trends. Cultural energy input in the form of woody plant control is required to change the vegetation configuration of these ecosystems. Anthropogenic input conceptualized and designed based on the intermediate disturbance hypothesis can maximize landscape diversity and may result in a landscape mosaic that supports greater species richness, provides increased forage for livestock, and enhances habitat for many wildlife species. A problem with this approach is that continuing inputs are required to maintain the selected landscape architecture. Development of models to predict the effects of woody plant control patterns on biodiversity will enable range managers to implement management strategies that maintain or increase plant and vertebrate species richness and diversity.
    • Importance of grasshopper defoliation period on southwestern blue grama-dominated rangeland

      Thompson, D. C.; Gardner, K. T. (Society for Range Management, 1996-11-01)
      Most economic assessments of grasshopper damage are based on how much plant tissue insects consume or destroy without considering factors that influence the ability of individual plants and communities to respond to damage. Properly grazed perennial warm-season grasses, such as blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Griffiths], can withstand considerable defoliation. We investigated the effects of heavy defoliation on blue grama rangeland by caging bigheaded grasshoppers [Aulocara elliotti (Thomas)] during early, mid, and late growing seasons for 2 years in southwestern New Mexico. Peak standing crop (PSC) of blue grama defoliated in the early-season was the same as that in cages protected from defoliation both years. However, peak standing crop of blue grama was reduced in cages defoliated during the mid and late growing seasons in both years. The importance of midseason feeding was compounded by significant changes in relative proportions of various herbage categories in the standing crop. Forbs and sedges made up a larger percentage of the total forage production at PSC after mid-season defoliation during both years. On rangelands where blue grama is dominant, even very high densities of early-season grasshoppers may not influence herbage production. Substantial declines in grasshopper densities observed before summer rains during both years should influence management decisions. Unless early-season forb production is an important part of a ranch management plan, the damage potential of early- and mid-season grasshopper species may be lower on southwestern rangelands where mid- to late-summer precipitation patterns occur than reported in the literature for other areas of the western United States due to later maturation of warm-season grasses. In most years, depending upon precipitation patterns, there may be adequate growth following heavy early-season herbivory to feed both livestock and grasshoppers.