• Changes in pinyon-juniper woodlands in western Utah's Pine Valley between 1933-1989

      Yorks, T. P.; West, N. E.; Capels, K. M. (Society for Range Management, 1994-09-01)
      Changes in woodland vegetation integrate the consequences of livestock grazing intensity, the alteration of fire regimes, and possible climate alterution, as well as other factors. Quantitative measurements of these changes, if taken over sufficient intervals, can allow evaluation of conservation management strategies. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah was described from circular 19-m2 plots located every 42 m. The major intermediate management treatment has been reduction of grazing pressure by introduced animals, although a fraction of the area was chained and burned in 1977. During a period climatically and phenologically similar to the original study, we reexamined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. Significantly greater shrub and perennial grass covers (more than threefold increases) were found in 1989, even where overall dominance is still by pinyon-juniper [Pinus monophylla (Torrey & Fremont) and Juniperus osteosperma (Torrey) Little]. This change is more obvious on steeper slopes away from roads and water, where both human and livestock disturbances would be expected to be minimized. Except in the chained portion, the observed shifts in dominance/diversity are contrary to widely accepted expectations.
    • Perceptions vs. recommendations: A rangeland decision-making dilemma

      Rowan, R. C.; Ladewig, H. W.; White, L. D. (Society for Range Management, 1994-09-01)
      This paper analyzes subjective perceptions of Texas ranchers concerning management decision-making to obtain insight for improving technology transfer. Correlations among variables from a 1990 mail questionnaire were transformed by principal component analysis into a small number of "new" variables representing unobservable patterns of behavioral similarities. Two principal components explained variability in rancher's perceptions for each of the areas of interest: stocking rate factors, grazing program benefits, and weed/brush treatment techniques. Stocking rate and grazing program components were each characterized by traditional and nontraditional factors. Ranchers perceived the primary benefit from instituting a grazing program to be improved livestock performance (traditional grazing component 1). Some modification of ranchers' perceptions about the primary benefits of grazing programs is indicated. Weed/brush decision-making was characterized by information-source and economic factors. The information-source component was defined by the importance of advice from neighbors and fear of treatment methods. Because these tend to be negative perceptions, both of these variables have the potential for restricting adoption of weed/brush technology.
    • Understanding cause/effect relationships in stocking rate change over time

      Rowan, R. C.; White, L. D.; Conner, J. R. (Society for Range Management, 1994-09-01)
      Decisions made by Texas ranchers over a 10 year period (1980-1990) concerning stocking rate levels were dominated by perceptions about weather. A regression model explained 64% of the variability in stocking rate change over time, with the rainfall/drought variable explaining the majority of variability. As ranchers' perception of a positive rainfall effect increased, so did stocking rates, and vice versa. Although the presence or absence of rainfall cannot be managed per se, proactive stocking decisions should include a strategy for adjusting stocking levels in response to changing environmental conditions. Other factors with significant (alpha = 0.05), albeit trivial, path coefficients on stocking rate change were age, grazing rights (owned vs. leased), traditional stocking rate factors, traditional grazing program factors, and weed/brush information factors. Older ranchers (> 65 years) and ranchers who leased all of their rangeland tended to decrease stocking rates over time. Rangeland operators indicated they considered "improved livestock performance" as the most important benefit from initiating a grazing program. Evidence also suggested that ranchers who rely on their neighbors for advice about weed/brush decisions are not benefitting from the latest technology information. Adoption of economic factors (cost/benefits) for selection of weed/brush technology did not have a significant impact on stocking rates over the 10 year period.