• Activated charcoal and experience affect intake of juniper by goats

      Bisson, M. G.; Scott, C. B.; Taylor, C. A. (Society for Range Management, 2001-05-01)
      Goats consume juniper, but toxic terpenoids within the plant limit intake. Our objective was to determine if dosing goats with the adsorptive compound activated charcoal would increase juniper consumption. Twenty Boer-cross goats were placed in individual pens; at 0800 hours, 10 were dosed with 1 g kg(-1) body weight (BW) of activated charcoal in an aqueous solution, and 10 were not dosed. Dosing occurred daily for 10 days. Goats were offered redberry juniper (Juniperus pinchotii Sudw.) in Trial 1, ashe juniper (Juniperus ashei Buch.) in Trial 2, and a choice between redberry and ashe juniper in Trial 3. For each trial, juniper was offered to all goats for 2 hours after dosing with activated charcoal. In Trial 1, goats dosed with activated charcoal consumed more (P < 0.05) redberry juniper during the first 5 days of exposure. In Trial 2, activated charcoal did not affect ashe juniper intake. In Trial 3, dosing with activated charcoal did not affect juniper intake. All goats preferred ashe to redberry juniper. Juniper intake increased across days of exposure for Trials 1 and 2, apparently because goats adapted to the terpenoids in juniper through repeated exposure. It appears that activated charcoal will only increase redberry juniper intake during initial exposures.
    • Activity budgets and foraging behavior of bison on seeded pastures

      Rutley, B. D.; Hudson, R. J. (Society for Range Management, 2001-05-01)
      Activity budgets and foraging behavior of yearling bison (Bison bison L.) on pasture were studied during quarterly trials between June 1994 and December 1995. Daily activity patterns were polyphasic with alternating bouts of foraging and resting activity. During winter, bison displayed 2 main daytime foraging bouts and significant nighttime foraging. During summer, phasic activity was poorly expressed due to the increased number of cycles. Total foraging time declined from summer to winter (763 +/- 62 to 470 +/- 32 min day(-1)) while bedding bout length increased (121 +/- 13 to 276 +/- 26 min day(-1)). Bison selected forage higher in crude protein (12.9 +/- 0.8 vs 10.0 +/- 0.8%), higher in predicted digestible energy (2.70 +/- 0.09 vs 2.17 +/- 0.09 Mcal kg(-1)), lower in acid detergent fiber (31.9 +/- 0.9 vs 38.8 +/- 0.9%), and lower in lignin (4.8 +/- 0.3 vs 6.8 +/- 0.3%, respectively) than forage available within grazed patches.
    • Antelope bitterbrush seed production and stand age

      Clements, C. D.; Young, J. A. (Society for Range Management, 2001-05-01)
      Antelope bitterbrush (Purshia tridentata (Pursh) DC) is the most important browse species on many western mule deer (Odocoileus hemionus) ranges. Lack of antelope bitterbrush seedling recruitment is a critical problem, and therefore, the influence of livestock grazing on antelope bitterbrush seed production is an important issue. Seed production was compared in grazed and ungrazed communities during 1995 and 1996 at 2 locations in northeastern California and one location in northwestern Nevada. A system of seed traps was used to estimate seed production in relation to the size, age and grazing of antelope bitterbrush plants in the various stands. Antelope bitterbrush seed production was significantly (P less than or equal to 0.01) higher at one of the ungrazed sites. Significant (P less than or equal to 0.05) differences in shrub ages were also recorded between sites.
    • Application of non-equilibrium ecology to rangeland riparian zones

      Stringham, T. K.; Krueger, W. C.; Thomas, D. R. (Society for Range Management, 2001-05-01)
      Traditional theories of plant succession leading to a single equilibrium community are being re-evaluated. Alternative theories involving multiple steady states, and state-and-transition processes have been postulated to more adequately reflect the dynamics of rangeland ecosystems. The ecological literature provides examples of apparent thresholds in arid and semi-arid plant communities, however the literature is void of discussion of the applicability of non-equilibrium ecological theory to riparian areas contained within the rangelands of the world. In arid and semi-arid environments the availability of soil water is critical in the determination of the composition of the plant community. In this study we hypothesized that the relationship between soil moisture and depth to groundwater within the riparian zone controlled the composition of the associated plant communities. These soil water, groundwater, plant community composition relationships were used to test the applicability of state and transition models to riparian zones. Water table levels within an irrigated eastern Oregon riparian valley were monitored for 2 consecutive summers. The study area was mapped into 4 distinct plant community types on the basis of dominant graminoids. We measured depth to the water table, soil moisture content, relative species composition, litter, percent bareground and percent relative basal cover of key plant species and life forms. Relationships between water table levels, soil moisture content and plant communities were analyzed. Results indicated the 4 plant communities contained within this study area can be segregated on the basis of soil moisture content and/or depth to groundwater during the growing season. Ecological states and transition zones based on soil moisture content and/or water table depth were determined.
    • Breeding bird responses to juniper woodland expansion

      Rosenstock, S. S.; Van Riper, C. (Society for Range Management, 2001-05-01)
      In recent times, pinyon (Pinus spp.)-juniper (Juniperus spp.) woodlands have expanded into large portions of the Southwest historically occupied by grassland vegetation. From 1997-1998, we studied responses of breeding birds to one-seed juniper (J. monosperma) woodland expansion at 2 grassland study areas in northern Arizona. We sampled breeding birds in 3 successional stages along a grassland-woodland gradient: un-invaded grassland, grassland undergoing early stages of juniper establishment, and developing woodland. Species composition varied greatly among successional stages and was most different between endpoints of the gradient. Ground-nesting grassland species predominated in uninvaded grassland but declined dramatically as tree density increased. Tree- and cavity-nesting species increased with tree density and were most abundant in developing woodland. Restoration of juniper-invaded grasslands will benefit grassland-obligate birds and other wildlife.
    • Canadian bluejoint response to heavy grazing

      Collins, W. B.; Becker, E. F.; Collins, A. B. (Society for Range Management, 2001-05-01)
      A disclimax stand of Canadian bluejoint (Calamagrostis canadensis (Michx.) Beauv.) was heavily grazed by cattle and horses for 4 years to weaken the grass's competition with hardwoods important as browse and cover to wildlife. Stocking at 0.084 ha AUM(-1) resulted in uniform utilization of bluejoint and maintenance of early phenology through the growing season. Etiolated bluejoint declined about 90%, but grass production increased 10 to 15%, as fireweed (Epilobium angustifolium L.), a principal herbaceous component of the stand, decreased in response to trampling. Rhizomes of heavily grazed bluejoint had lower total nonstructural carbohydrates (TNC) (p = 0.0127), lower weight (g cm(-1) length) (p = 0.05), and reduced biomass (g cm(-3) of soil) (p = 0.05). Shoots of grazed bluejoint maintained higher nitrogen (p = 0.0001) and higher digestibility (IVDMD) (p = 0.0017) than bluejoint that was never grazed. This enabled heavily grazed bluejoint to retain good forage quality through the entire growing season, as opposed to ungrazed bluejoint, which became poor forage at the time of flowering during early July. Following one season of rest, rhizome TNC, shoot nitrogen, and IVDMD returned to levels of never grazed bluejoint. Seedhead production, seed production, seed weights, and seed viability of rested bluejoint were about the same as in ungrazed stands. On wet sites, heavy grazing does not adequately reduce the vigor of this grass.
    • Cattle preferences for Lambert locoweed over white locoweed

      Ralphs, M. H.; Greathouse, G.; Knight, A. P.; James, L. F. (Society for Range Management, 2001-05-01)
      White (Oxytropis sericea Nutt. in T. G.) and Lambert (O. lambertii var. biglovii Pursh) locoweed grow adjacent to each other on the foothills of the Rocky Mountains from southeastern Wyoming to northeastern New Mexico. Lambert locoweed matures later and flowers about 3-4 weeks after white locoweed, thus potentially increasing the critical period of poisoning when livestock graze areas infested by both species. The objective of this study was to evaluate cattle consumption of these 2 species as they progress phenologically. In 1998, 15 Hereford cows grazed a 32 ha pasture infested with both species from the time white locoweed flowered in mid June until both species were mature and senesced in August. In 1999, 4 cows were placed in a 5 ha pasture infested with both species for 4 days in each of the following periods: (1) flower stage of white locoweed, (2) flower stage of Lambert locoweed, immature pod at white locoweed, (3) immature pod stage of Lambert locoweed, mature pod while (4) mature pod and seed shatter stage respectively. Diets were estimated by bite-count. Lambert locoweed was preferred over white locoweed in the season-long grazing trial in 1998, and in each of the 4 intensive grazing trials in 1999. The cows consumed white locoweed as availability of Lambert locoweed declined in 1998, but little white locoweed was consumed in the 4 intensive grazing trials in 1999. The toxic locoweed alkaloid swainsonine ranged from 0.04 to 0.06% in white locoweed, but was not detected in Lambert locoweed in this study.
    • Characteristics of nest sites of northern bobwhites in western Oklahoma

      Townsend, D. E. II.; Masters, R. E.; Lochmiller, R. L.; Leslie, D. M.; DeMaso, S. J.; Peoples, A. D. (Society for Range Management, 2001-05-01)
      Previous authors have described nesting habitat of the northern bobwhite (Colinus virginianus) throughout its range, but few have compared structural or compositional differences of vegetation between nest sites and random non-use sites, and successful and non-successful nests. From 1996-1998, we compared cover and structure of 85 plant species from 80 nest sites of northern bobwhite in western Oklahoma. Nest sites were consistently associated with greater structural complexity than what was available at random. Bobwhites selected nest sites with a greater coverage of grass (ca. 50%) and woody (ca. 20-30%) vegetation with a relatively low percentage of bare ground, presumably because these attributes maximize their chance for successful reproduction by providing protection against weather and predators. Successful nests were more concealed during 1996 and 1997 (12.37 and 10.74% visibility, respectively) than non-successful nest sites (21.6 and 27.65% visibility), but levels of concealment did not differ during 1998. We found no significant differences in vegetation composition or structure between successful and non-successful nest sites.
    • Comparative rumen and fecal diet microhistological determinations of European mouflon

      Chapuis, J. L.; Boussés, P.; Pisanu, B.; Réale, D. (Society for Range Management, 2001-05-01)
      The population of European mouflon (Ovis musimon Pallas) established on an island of the sub-Antarctic Kerguelen archipelago is characterized by a demographic cycle. Every 2-5 years, there is a massive winter mortality due to food shortage. A good knowledge of food resources utilization appeared essential to understand the population growth dynamics. We investigated the validity of the microhistological analysis of feces by a comparative analysis of 30 paired rumen and fecal samples collected in winter. Sixteen and 17 food items were identified respectively in rumen and fecal samples. Most fragments could be accurately determined because plant diversity was low. Both methods gave similar results Though quantitative differences appeared between methods for some items, the same 4 major food constituents were identified in relatively close proportions in both rumen and fecal samples. There is a risk of slight overestimation of annual meadow-grass (Poa annua L.) and mosses in feces, and of Azorella selago Hook. f. in the rumen.
    • Drought and grazing III: Root dynamics and germinable seed bank

      Hild, A. L.; Karl, M. G.; Haferkamp, M. R.; Heitschmidt, R. K. (Society for Range Management, 2001-05-01)
      Drought and herbivory frequently influence North American rangelands. While these influences may temporarily reduce vegetative cover, their mutual influence on the available seedbanks which might occupy new safe sites is unclear. We examine effects of drought and grazing upon pre- and post-drought plant root distribution and germinable seed bank to determine 1) if the response of root distributions to drought depends upon grazing use and 2) if the presence of germinable seeds is altered significantly by drought and grazing. Using twelve, 5 X 10 m non-weighing lysimeters with an automated rainout shelter, we documented root intercepts in situ using a minirhizotron from 1993-1996. Seed bank samples were incubated in a greenhouse to determine seedling emergence. Roots were fewer in shallow soil layers in grazed plots than ungrazed plots by the end of the study, irrespective of drought. Roots in deeper (Bw horizon) soil layers were fewer during drought, but were not influenced by grazing. Seed bank composition results suggest that perennial grasses were a small portion of the seed bank. Cool-season annual grass seeds accumulated after drought. Without drought, forb seed banks increased with grazing. Thus while shallow roots may decrease during drought, in the year following drought grazing may decrease aboveground net primary production, and allow large accumulations of cool-season annual grass seed in a northern mixed grass prairie.
    • Escape protein and weaning effects on calves grazing meadow regrowth

      Lardy, G. P.; Adams, D. C.; Klopfenstein, T. J.; Clark, R. T.; Emerson, J. (Society for Range Management, 2001-05-01)
      Forty spring-born calves grazing subirrigated meadow regrowth after haying in July were assigned to 2 weaning and 2 supplementation treatments in fall of 1995 and 1996. Weaning treatments were weaning on 1 September or nursing during the duration of the trial. Supplementation treatments were no supplement or supplemental undegraded intake protein (UIP). An 80:20 (dry matter basis) blend of sulfite liquor treated soybean meal and feather meal was the source of undegraded intake protein (undegraded intake protein = 45% of supplement dry matter). Supplemented nursing calves received 0.50 kg of supplement daily whereas supplemented weaned calves received 0.91 kg of supplement daily. Weaned and nursing calves grazed subirrigated meadow regrowth throughout the trial. The trials were conducted from 17 October to 18 November 1995 and 5 September to 4 November 1996. Milk intake was measured by the weigh-suckle-weigh technique. Diet samples collected from ruminally cannulated calves after rumen evacuation averaged 12.5% crude protein and 54.8% in vitro organic matter digestibility. No supplementation x weaning management interactions were detected (P > 0.18). Nursing calves had greater weight gains (0.95 vs. 0.59 kg day(-1); P = 0.001) and lower forage intakes (2.36 vs. 2.96 kg day(-1); P = 0.009) than weaned calves. Supplementation with undegraded intake protein increased (P = 0.03) daily gains of calves compared to nonsupplemented calves 0.88 vs 0.66 kg day(-1), respectively. Forage intake as a percentage of body weight tended to be higher in non-supplemented calves (P = 0.09). However, total intake (forage plus supplement) as a percentage of body weight tended to be higher in supplemented calves (P = 0.14). Total intake (kg day(-1)) was greater (P = 0.01) for calves supplemented with undegraded intake protein. Milk intake did not differ between supplemented and unsupplemented calves (P > 0.52). We concluded that subirrigated meadow regrowth forage was limiting in metabolizable protein and that milk represents an important source of metabolizable protein for grazing calves.
    • Forage kochia seed germination response to storage time and temperature

      Kitchen, S. G.; Monsen, S. B. (Society for Range Management, 2001-05-01)
      The Eurasian low-shrub, forage kochia [Kochia prostrata (L.) Shad.], was introduced into western North America for use in restoration of severely disturbed landscapes in arid and semiarid environments. Seed mature in late fall and are short-lived in typical warehouse conditions. In a preliminary, cold-temperature experiment (2 degrees C) using 3-month-old seed from 16 forage kochia accessions, mean germination time, expressed as days to 50% germination, varied from 4 to 88 days. Follow up experiments using seed of 5 accessions tested the effects of storage time and temperature on seed viability and mean germination time and related this to field planting success. Sub-samples were air-dried and stored in plastic bags in a freezer, cold room, and lab (-15, 2, and 20 degrees C respectively). A fourth set of subsamples was stored in a shed with no temperature control (simulated warehouse storage). Seed were tested fresh and retested after 4, 8, 12, 24, and 36 months of storage. Mean viability decreased from 77% (range 66 to 93%) for recently harvested seed, to 24 and 8% for lab- and shed-stored seed, after 36 months of storage. No significant change in viability was observed for cold room- and freezer-stored seed. Across all accessions, cold temperature mean germination time (MGT) for recently harvested seed was 73 days (range 51 to 109 days). For each accession, germination occurred primarily over a 70 day period. Mean germination time decreased as storage time increased for lab- and shed-stored seed, varied unpredictably for cold room-stored seed, and remained unchanged for freezer-stored seed. Field germination using 1- and 2-year old lab- and shed-stored seed was significantly faster than that of same-aged cold room- and freezer-stored seed. The number of live seedlings 4 months after planting for cold room- and freezer-stored seed was 10-fold or greater than that of lab- and shed-stored seed. Thus a delayed, asynchronous cold-temperature germination pattern appears to be adaptive for forage kochia establishment. Cold, dry storage prevents loss of seed viability and preserves this desirable germination pattern.
    • Herbage response to precipitation in central Alberta boreal grasslands

      Bork, E. W.; Thomas, T.; McDougall, B. (Society for Range Management, 2001-05-01)
      The dependence between grassland herbage production and precipitation within the Boreal region of central Alberta was evaluated. Additional objectives were to compare current year growing season (e.g., April or May, to August) precipitation with 12 and 16 month water year (e.g., dormant and growing season) precipitation for use in predicting herbage growth, and determine whether lowland and upland grasslands differ in their response to precipitation. Lowland herbage production averaged 6,053 kg ha(-1), nearly twice the 3,153 kg ha(-1) found on upland grasslands during the study. In general, herbage production correlated significantly with precipitation, but the magnitude and direction of that relationship varied depending on grassland type. Uplands displayed a positive linear relationship with precipitation (r = 0.76; p < 0.01), while lowland communities displayed a negative curvilinear (R2 = 0.65; p < 0.05) relationship. Furthermore, while herbage production on uplands was better predicted by current year precipitation, lowland production appeared more heavily dependent on precipitation falling during the water year, the latter of which included fall and winter moisture recharge. We hypothesize that these differences are linked to water redistribution within the landscape, along with subsequent soil temperature regimes and the length of effective growing season. Given the influence of topography in regulating water availability and use, rangeland managers within the Boreal region should use caution when determining rangeland carrying capacity from meteorological data.
    • Remote sensing of redberry juniper in the Texas rolling plains

      Everitt, J. H.; Yang, C.; Racher, B. J.; Britton, C. M.; Davis, M. R. (Society for Range Management, 2001-05-01)
      Redberry juniper (Juniperus pinchotii Sudw.) is a noxious shrub or small tree that invades rangelands in northwest Texas. Field reflectance measurements showed that redberry juniper had lower visible and higher near-infrared (NIR) reflectance than associated species and mixtures of species in February. The low visible reflectance of redberry juniper was due to its darker green foliage than associated species, whereas its high NIR reflectance was attributed to its greater vegetative density than associated vegetation. Redberry juniper had a distinct reddish-brown image tonal response on color-infrared aerial photographs obtained in February. Computer analysis of a color-infrared photographic transparency showed that redberry juniper infestations could be quantified. An accuracy assessment performed on the classified image had a user's accuracy of 100% and a producer's accuracy of 94% for redberry juniper.
    • Restoring degraded riparian meadows: Biomass and species responses

      Martin, D. W.; Chambers, J. C. (Society for Range Management, 2001-05-01)
      Riparian meadows in central Nevada are highly productive and have been extensively utilized for livestock grazing. Consequently, many have been severely degraded resulting in changes in species composition and decreases in productivity. During a 3 year study, we examined the responses of mesic meadow systems to yearly nitrogen addition (100 kg ha(-1)) and clipping (8-10 cm stubble height) to increase our understanding of grazing effects. We also examined the effects of a one-time, fall aeration (10 cm deep by 2 cm wide holes spaced 20 cm apart) and revegetation (removal of existing vegetation and reseeding) to evaluate the restoration potential of these sites. Changes in total biomass, species aerial cover and frequency, and surface basal cover were used to evaluate treatment responses. Clipping had no effect on total biomass, possibly because it was conducted late in the growing season. In contrast, nitrogen addition plus clipping increased biomass in all 3 years when treatments were compared across sites and for 1 out of 3 years when treatments were compared across a single site. Aeration had no effect on above ground biomass, but has been shown to increase rooting activity in these same meadows. Due to a dry, hot spring, early seral and weedy species had higher establishment than the seeded natives in the revegetation plots, and biomass was low the first year after treatment. Individual species varied in their treatment responses. The cover of low-growing forb species (western aster (Aster occidentalis [Nutt.] Torrey and A. Gray), long-stalk starwort (Stellania Longipes Goldie), and common dandelion (Taraxacum officinale Wigg.) declined through time for all treatments, presumably due to increased grass cover and shading following release from grazing and above average precipitation and water table levels in 1998. Examination of the key graminoids showed that Kentucky bluegrass (Poa pratensis ssp. pratensis L.), an increaser species, did not increase in response to release from grazing, but increased in response to clipping and nitrogen addition. Nebraska sedge (Carex nebrascensis Dewey), a desirable native, increased in response to both release from grazing and nitrogen addition. The results were influenced by high spatial and temporal variability in water table elevations within these systems.
    • Species composition on reclaimed ski runs compared with unseeded areas

      Van Ommeren, R. J. (Society for Range Management, 2001-05-01)
      The cover of native and non-native introduced plants was compared between seeded (reclaimed) ski runs and adjacent or nearby unseeded (control) areas at a managed ski area in northern Arizona to determine the potential effects of revegetation efforts on plant species composition of the area. Although vegetative cover was similar, plant species richness was significantly lower on reclaimed ski runs compared with control areas. At 3 of 4 sites, the number of plant species was more than 2-fold greater in control areas, although species richness was similar between control and reclaimed areas at 1 site. The proportion of native species was more than 3-fold greater in control areas compared with reclaimed ski runs. The proportion of non-native species was more than 5-fold greater on reclaimed ski runs than in control areas. Although sites differed substantially in time since seeding, no evidence was found at 3 of the 4 sites for either an invasion of non-native species into the native plant community, or significant re-establishment of native species in reclaimed areas. Relatively high biomass of native species on a reclaimed ski run at 1 site appeared to be tied to a low level of initial disturbance and favorable conditions for growth. Results suggested that minimizing initial soil disturbance, retaining topsoil, and maintaining islands or patches of natural vegetation within cleared areas promoted the re-establishment of native species on ski runs.
    • The nutritive quality of cholla cactus as affected by burning

      Sawyer, J. E.; Knox, L. A.; Donart, G. B.; Petersen, M. K. (Society for Range Management, 2001-05-01)
      Cholla cactus may serve as an emergency feedstuff for livestock when forage availability is low. A study was conducted at the Corona Range and Livestock Research Center to evaluate the nutritive quality of cholla cactus (Opuntia imbricata) after spine removal. Six samples were collected for each treatment in a completely randomized design. Treatments consisted of spine removal by burning with a propane torch (BURN), or leaving spines intact (UN). Each sample consisted of 2 burned and 2 unburned cladodes from each of 5 plants. One sample from each treatment was weighed immediately after collection and used solely for dry matter (DM) determination. Remaining samples were evaluated for crude protein (CP), organic matter (OM), neutral detergent fiber (NDF), and mineral composition. Rate and extent of ruminal DM and OM disappearance were estimated in situ for 20 and 68 hours in the rumen of each of 2 cannulated cows grazing native rangeland. Dry matter contents of burned and unburned cholla were 12.7% and 12.4% respectively. Crude protein was not affected by burning (P > 0.6; 13.0% UN, 13.6% BURN, SE +/- 0.7). Burning reduced OM (82.4% UN, 81.0% BURN; SE +/- 0.4) and NDF (48.6% UN, 39.2% BURN; SE +/- 1.8) content (P < 0.03). Reduced NDF contributed to increased rate and extent of ruminal OM disappearance for burned cholla (P 0.03). Mineral content was minimally affected by burning. Measurements indicate that cholla has relatively high nutrient quality, but the high moisture content would require large amounts to be fed as an emergency feed source.