• Sites, mowing, 2,4-D, and seasons affect bitter-brush twig morphology

      Kituku, V. M.; Powell, J.; Olson, R. A. (Society for Range Management, 1994-05-01)
      Effects of site factors, mowing, 2,4-D, and seasons on antelope bitterbrush (Purshia tridentata Pursh.) twig length, basal and tip diameters, and weight were evaluated in southcentral Wyoming. Linear regression coefficients for twig length regressed on basal diameter were greater on productive sites than on less productive sites, greater on mowed areas than on sprayed or untreated areas, and greater in late fall because of leaves than in late winter. Twig elongation continued after data collection in early November. Twig length was more variable and more sensitive to different environmental conditions than twig basal diameter, tip diameter, or weight. Twig length accounted for 80-86% of the variation in twig weight. Sites, shrub management practices, and seasons do affect bitterbrush twig morphology, but habitat managers can use twig length-diameter-weight relations in this vegetation type to estimate utilization if the sampling is stratified along environmental gradients.
    • Sixty-one years of secondary succession on rangelands of the Wyoming high plains

      Samuel, M. J.; Hart, R. H. (Society for Range Management, 1994-05-01)
      The slow and uncertain rate of recovery of plant communities after severe disturbance is a major problem on rangelands. Earlier studies sketched the outline of secondary succession on mixed-grass prairie, but were based on 1 or 2 years of observation on different areas disturbed at different times in the past, or several years of observation of a single area. To provide a more complete picture of succession over decades, we began observations in 1977 on 4 areas disturbed from 1 to 51 years previously, and on undisturbed areas of the same 2 soil types with and without grazing. Observations continued for 11 years. Secondary succession proceeded through the usual stages: annual forbs, perennial forbs and annual grasses, short-lived perennial grasses, and long-lived grasses. Western wheatgrass [Pascopyrum smithii (Rydb.) A Love] was an exception because it appeared much earlier and in much greater abundance than other long-lived perennial grasses. Blue grama [Bouteloua gracilis (H.B.K.) Lag ex. Steud.) may be another exception; total recovery of this grass may require centuries. Time of appearance in succession seemed to be related to availability of propagules and ease of establishment; persistence of species was related to competitive ability. Abundance of many species fluctuated widely from year to year, but fluctuations did not appear to be related to precipitation. After 61 years, secondary succession had not returned plant communities to the climax state.
    • Technical Note: Inexpensive rain gauges constructed from recyclable 2-liter plastic soft drink bottles

      Wrage, K. J.; Gartner, F. R.; Butler, J. L. (Society for Range Management, 1994-05-01)
      A large number of inexpensive rain gauges were required for a study currently being conducted in the Black Hills of South Dakota. A gauge utilizing discarded 2-liter plastic soft drink bottles was designed and constructed at very low cost. Assembly took less than 5 minutes per gauge and required minimal equipment. The gauges have been in use for 1 growing season and have provided accurate, reliable data.
    • Technical Note: Mechanical harvesting of plains pricklypear for control and feeding

      Mueller, D. M.; Shoop, M. C.; Laycock, W. A. (Society for Range Management, 1994-05-01)
      Plains pricklypear cactus (Opuntia polyacantha L.) is abundant on the Central Great Plains with dry matter yields from 1,500 to 2,000 kg/ha. Cactus spines prevent cattle from grazing as much as 50% of the herbage around the plant. Pricklypear pads are quite palatable once spines have been removed. The possibility of simultaneously controlling and feeding plains pricklypear led to development of machinery for harvesting cactus. The harvesting machine is a side-delivery rake modified to uproot and windrow pricklypear which is later despined and fed to cattle. Machine harvesting was compared to hand harvesting on both a sandy loam and a clay loam site. There was no significant difference in cactus removal between hand and machine harvested plots or significant damage to desirable forage species. Pricklypear phytomass removal by the harvester averaged 89% and 88% on the sandy and clay loam sites, respectively. This provided an average of 1,166 kg/ha cactus as potential feed and increased availability of desirable forage species.
    • Tiller defoliation patterns under frontal, continuous, and rotation grazing

      Volesky, J. D. (Society for Range Management, 1994-05-01)
      An investigation was conducted to characterize the intensity and frequency of tiller defoliation in 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng) under frontal, continuous, and 2-paddock rotation grazing systems. Frontal grazing allows cattle a continuous opportunity to graze fresh forage via a livestock-pushed sliding fence that allocates and controls grazing within a pasture. Nearly 100% of frontal grazing tillers were defoliated at least once during a 3-hour period as the frontal fence was advanced over the transect ares. The initial defoliation intensity of tillers under frontal grazing was also significantly higher and remaining tiller height less than that of tillers under rotation or continuous grazing (P < 0.05). Tillers under frontal grazing were defoliated at a faster rate compared to rotation or continuous grazing, but cattle had access to them for only 6 to 8 days of the entire grazing season. Season-long defoliation frequency was estimated to be 2.4, 4.6, and 4.7 times for frontal, continuous, and rotation grazing, respectively. Tillers that originated from the perimeter of a tussock were initially taller than those arising from the center (P < 0.05); however, frequency and intensity of defoliation was similar for both tiller locations. Significant relationships were also described between defoliation frequency and stocking rate and between defoliation frequency and herbage allowance. Defoliation frequency increased linearly as stocking rate increased; and conversely, defoliation frequency decreased quadratically as herbage allowance increased. Data from this study suggest that the pattern of tiller defoliation under frontal grazing enhanced forage production which allowed the maintenance of higher stocking rates.
    • Vegetation characteristics influencing site selection by male white-tailed deer in Texas

      Pollock, M. T.; Whittaker, D. G.; Demarais, S.; Zaiglin, R. E. (Society for Range Management, 1994-05-01)
      We studied the effects of vegetation characteristics in southern Texas on site selection by mature, male white-tailed deer (Odocoileus virginianus Raf.). Thirteen, radio-collared animals were monitored during winter, spring, summer, and fall of 1986-87 and 1987-88 to determine area-usage patterns within each animal's respective seasonal home range. After each season, structural vegetation attributes were measured with transect-oriented data collection techniques inside the most heavily used and unused areas of each animal's home range. Comparisons were made between these areas to determine whether site selection by deer was in response to differing vegetation characteristics. In general, the most heavily used areas possessed a greater amount of woody canopy cover (greater than or equal to 85%), woody species richness (18-20), and horizontal screening cover than areas with no use. In contrast, herbaceous densities did not differ between the most heavily used and unused areas. Consequently, habitat management manipulations conducted specifically for mature male white-tailed deer in southern Texas, should include provisions for creation or maintenance of sites possessing dense woody canopy cover, a high number of woody species and dense horizontal screening cover.