• Vegetation of Exclosures in Southwestern North Dakota

      Brand, M. D.; Goetz, H. (Society for Range Management, 1986-09-01)
      A 3-year study of the vegetation in 4 livestock exclosures was begun in 1976 in the mixed grass prairie of southwestern North Dakota. Three of the exclosures were established in 1937 and the fourth in 1938. The exclosures had greater graminoid leaf heights and greater mulch accumulations than the adjacent grazed plots; however, total yield and total belowground biomass were not significantly different between plots in 3 out of the 4 sites. The major difference between the exclosures and the adjacent grazed plots was species composition. The production of blue grama (Bouteloua gracilis (H.B.K.) Griffiths) was lower, and the production of thread-leaf sedge (Carex filifolia Nutt.) and another sedge (Carex heliophila Mack.) was greater in the exclosures than on the adjacent grazed plots. A summary by growth form also showed that the midgrass and tallgrass growth form category was more dominant in only 1 out of 4 exclosures. The interpretation of these data indicates that the potential for changes in growth form dominance and total yield due to management inputs must be evaluated on a site specific basis. Species composition also was a more reliable indicator of successional status than growth form dominance.
    • Vegetation Responses to Long-Term Sheep Grazing on Mountain Ranges

      Bowns, J. E.; Bagley, C. F. (Society for Range Management, 1986-09-01)
      Some high-elevation summer ranges in southwestern Utah are characterized by a dominance of grass and low-value forbs. A reference area of forb dominance provides a striking contrast to these grass ranges. The reference area has a greater number of total species and a greater number of forbs. Production (above-ground live biomass) is nearly 2 times as great in the reference area as in the surrounding pastures. Production of desirable species in the reference area is greater than the production of desirables, intermediates, and least desirables in the surrounding pastures. It is suggested that the grass dominance on these ranges is due to a long and persistent history of exclusive sheep grazing.
    • Viewpoint: Animal-Unit Equivalents Should Be Weighted by Dietary Differences

      Hobbs, N. T.; Carpenter, L. H. (Society for Range Management, 1986-09-01)
    • Woody Plants Reestablishment in Modified Pinyon-Juniper Woodlands, New Mexico

      Severson, K. E. (Society for Range Management, 1986-09-01)
      Pinyon (Pinus edulis Engelm.), one-seed juniper (Juniperus monosperma (Engelm.) Sarg.), and alligator juniper (J. deppeana Steud.) woodlands in southwestern New Mexico were thinned, were pushed with bulldozers leaving slash in place, and were pushed and then slash piled and burned. There were no significant differences (P>0.05) in densities of these trees 13 and 18 years later between untreated (379 trees/ha) and thinned (489 trees/ha) plots or between pushed/left (67 trees/ha) and pushed/piled/burned plots (49 trees/ha). Differences between bulldozed treatments and untreated/thinned treatments were significant (P<0.05). Total shrubs, 75% of which were gray oak (Quercus grisea Liebm.) and hairy mountainmahogany (Cercocarpus breviflorus Gray), were significantly more abundant in untreated areas (672 shrubs/ha), than in any of the treatments. No differences were noted among treatments (493, 393, 329 shrubs/ha for thinned, pushed/left, and pushed/piled/burned, respectively). Rates of pinyon reestablishment increased slowly up to the mid-1960's (from 1.1 to 1.3 trees/ha/year) then accelerated to 10 to 13 trees/ha/year. Pinyon and juniper densities were about 120 trees/ha when reestablishment rates increased.