• Responses of Birds, Rodents, and Vegetation to Livestock Exclosure in a Semidesert Grassland Site

      Bock, C. E.; Bock, J. H.; Kenney, W. R.; Hawthorne, V. M. (Society for Range Management, 1984-05-01)
      Livestock have been excluded from a 3,160-ha range in southeastern Arizona since 1968. Compared to an adjacent continuously grazed area, in 1981-82 a protected upland site supported 45% more grass cover, a comparatively heterogeneous grass community, and 4 times as many shrubs. Grama grasses (Bouteloua spp.) were equally common in and outside the exclosure, while a variety of other species, especially plains lovegrass (Eragrostis intermedia) and Arizona cottontop (Trichachne californicum) were much more abundant on the protected site. The grazed area supported significantly higher numbers of birds in summer, while densities did not differ in winter. Rodents were significantly more abundant inside the protected area. Species of birds and rodents more common in the grazed area included those typical of more xeric lowland habitats and those preferring open ground for feeding. Species more common on the protected site were those which characterize semidesert or plains grasslands, and which prefer substantial grass or shrub cover. Grazing appeared to favor birds as a class over rodents.
    • Ruminal Digestion Consistency of Zebu Cattle

      Hansen, R. M.; Whittington, D. L.; Child, R. D.; Wanyama, J. M. (Society for Range Management, 1984-05-01)
    • Seasonal Foods of Blacktail Jackrabbits and Nuttall Cottontails in Southeastern Idaho

      MacCracken, J. G.; Hansen, R. M. (Society for Range Management, 1984-05-01)
      The diets of blacktail jackrabbits (Lepus californicus) and nuttall cottontails (Sylvilagus nuttalli) were estimated by examination of fecal pellet botanical composition. The deficiencies of fecal analysis are noted, but dietary trends and relative importance of forage plants are accurate. Cluster analysis combined leporid pellets into 2 distinct groups based on botanical composition, representing feeding during spring-summer and fall-winter periods. Seven variables (plant species) accounted for significant differences (P<0.05) within and among the leporids studied in seasonal food selection. Generally, grasses and forbs were most abundant in blacktail jackrabbit and nuttall cottontail pellets during the spring-summer period, whereas shrubs were most abundant during the fall-winter period. Diet similarity was greatest between blacktail jackrabbits and nuttall cottontails during the same season. Diversity of forage consumed was greatest for both leporids during spring-summer periods. Habitat segregation minimizes competition for forage between the leporids studied. Livestock grazing appears to limit leporid population density rather than alter leporid food habits.
    • Semen Characteristics and Behavior of Grazing Bulls as Influenced by Shade

      Coleman, S. W.; Meyerhoeffer, D. C.; Horn, F. P. (Society for Range Management, 1984-05-01)
      The efficiency of shades to provide bulls relief from heat stress was studied during the summers of 1977 and 1978. The shades were constructed from steel pipe with expanded metal roof covered with baled straw. Ambient and blackbulk temperatures were more variable in 1977 than in 1978. No consistent influence of shade availability was observed in behavior of the bulls, though during 1978, less time was spent grazing by bulls with access to shade. During both years, standing time was greater (P<.10) by bulls without access to shade. Bulls made little use of the shades in August and September. In 1977, semen motility, movement rate, and percentage live sperm cells were greater (P<.10) from bulls provided shade. Bulls without shade showed a trend for higher numbers of aged acrosomes and abnormal sperm cells. General semen quality was lower in 1978, but no consistent effect of shade was noted, except that abnormal sperm cells were lower from bulls with access to shade. During both years, semen motility was decreased and percentage of abnormal sperm cells was increased 2- to 3-weeks after blackbulb temperatures approached 45 degrees C for several consecutive days.
    • Shade Tolerance of Grass and Legume Germplasm for Use in the Southern Forest Range

      Watson, V. H.; Hagedorn, C.; Knight, W. E.; Pearson, H. A. (Society for Range Management, 1984-05-01)
      A series of experiments was conducted during 1978, 1979, and 1980 to screen selected cultivars of grasses and legumes for their adaptation and performance under a multiple harvest system in a shaded environment. Acceptable stands of all species except Uniola sessiliflora Michx. were obtained under each shade treatment. The most shade tolerant species were 'Nangeela' subclover (Trifolium subterraneum L.), ryegrass (Lolium multiflorium Lam.), Persian clover (Trifolium resupinatum L.) and crimson clover (Trifolium incarnatum L.). Shade reduced the height of species with an upright growth habit while decumbent type species (subclover) showed less reduction. Nitrogen content was not affected by shade while potassium and phosphorus levels increased for all species under 50% shade. In separate field experiments the yield, stand density, and persistence of sericea lespedeza {Lespedeza cuneata (Dumont) G. Don} decreased with increasing shade although crude protein content was not affected. Cultivars of 4 species, ('Mt. Barker' subclover, 'Tibbee' crimson clover, 'Kentucky 31' tall fescue (Festuca arundinacea Schreb.), and 'Gulf' ryegrass), had acceptable stands and yields under 50% shade in a multiple harvest regime. These results demonstrate that several forage species are sufficiently shade tolerant to warrant consideration for use in forested environments.
    • Soil-Plant Factors in Early Browning of Russian Wildrye on Natrustoll Soils

      Bowman, R. A.; Mueller, D. M.; McGinnies, W. J. (Society for Range Management, 1984-05-01)
      The occurrence of early browning in selected areas of a 1979-established Russian wildrye (Elymus junceus Fisch.) plot led to a comparison of soil-plant-water relationships in the brown senescing areas, and in adjacent green healthy areas. Although the green areas exhibited better nutrient status and less salinity-sodicity associated problems than the brown areas, the main problem and cause for this premature browning appeared to be water related.
    • Stand Establishment: The Role of Seedling Size and Winter Injury in Early Growth of Three Perennial Grass Species

      White, R. S. (Society for Range Management, 1984-05-01)
      Winter damage and the subsequent number of viable leaves at the beginning of growth in spring were highly correlated with spring and fall seedling growth in crested wheatgrass, Russian wild ryegrass, and pubescent wheatgrass. As spring leaf numbers on individual plants increased from one to four, there was a corresponding increase in subsequent growth. As winter injury increased, seedling growth was reduced. These results suggest that late-summer seeding in the Northern Great Plains would hasten stand establishment and reduce the length of grazing deferment on newly seeded stands.
    • Summer Diets of Bison and Cattle in Southern Utah

      Van Yuren, D. (Society for Range Management, 1984-05-01)
      Diets of bison (Bison bison) and cattle (Bos taurus) were evaluated in a shrub-steppe plant community in the Henry Mountains, Utah. Bison feces comprised 99% grasses and sedges and 1% forbs. Cattle feces also were primarily grasses and sedges (95%), but in addition included significantly more forbs (5%) than did bison feces.
    • Temperature Profiles for Germination of Two Species of Winterfat

      Dettori, M. L.; Balliette, J. F.; Young, J. A.; Evans, R. A. (Society for Range Management, 1984-05-01)
      Germination of seeds of winterfat [Ceratoides lanata (Pursh) Howell] and Eurasian winterfat [C. latens (J.F. Gnel.) Reveal and Holmgren] was compared at 55 constant and alternating temperatures. The seeds of both species germinated at a wide range of temperatures. Optimum germination (defined as not lower than the maximum and its 0.01 probability confidence interval) occurred most frequently at 0, 2, and 5 degrees C cold period temperatures alternating with 15 and 20 degrees C. Optimum temperature regimes tended to be slightly warmer for seeds of Eurasian winterfat. There were large year-to-year differences in the quality of Eurasian winterfat seeds. Three sources of winterfat purchased from commercial seed dealers had low to very low germinability. Seeds of the Hatch selection of winterfat that we tested had a germination response equal to or better than the commercial sources of winterfat seeds.
    • Threshing Damage to Radicle Apex Affects Geotropic Response of Winterfat

      Booth, D. T. (Society for Range Management, 1984-05-01)
      The acute end of a winterfat [Eurotia lanata (Pursh) Moq.; Ceratoides 1. (Pursh) J.T. Howell] seed is formed by the apex of the radicle and of the cotyledons. It is postulated that this shape makes the embryo root cap especially susceptible to damage during threshing and that such damage is the cause of a high percentage of threshed germinated seed (germinant) lacking positive geotropism. This study consisted of examining germination behavior and post germination anatomy of the root apex of germinants with and without positive geotropism. The radicle apex was found to be damaged in 25% of the threshed seed. Eighty-five percent of the germinants from undamaged seed had positive geotropism as compared to 53% from the damaged seed. The latter had a range of anatomical aberrations in which the root cap was missing or seriously abnormal. It is concluded that the standard method of hammer mill threshing of winterfat fruits results in 25% of the seed sustaining damage to the radicle apex. This damage causes a loss of root cap functions, particularly the sensing of gravity. It is recommended that plantings be made by broadcasting whole fruits, rather than by drilling threshed seed.
    • Vegetation Change after 13 Years of Live-Stock Grazing Exclusion on Sagebrush Semidesert in West Central Utah

      West, N. E.; Provenza, F. D.; Johnson, P. S.; Owens, M. K. (Society for Range Management, 1984-05-01)
      Range managers often assume that release of vegetation from livestock grazing pressure will automatically result in a trend toward the pristine condition. The pathways and time scales for recovery are also sometimes assumed to be the same as for retrogression. These assumptions were examined via monitoring of plant community composition and forage production in five large paddocks of sagebrush semi-desert vegetation in west central Utah over a 13-year interval. No significant increases in native perennial grasses were noted over this period despite a trend toward more favorable precipitation in recent years. Thus, the present brush-dominated plant community is probably successionally stable. A return to vegetation similar to the original sagebrush-native grass mixture is unlikely. The possibility of a successional deflection via fire is enhanced by the increase of annual grass. Improvement of forage production in this vegetation will not necessarily follow after livestock exclusion. Direction manipulations are mandatory if rapid returns to perennial grass dominants are desired in such environments.