Vegetation differences in desert shrublands of western Utah's Pine Valley between 1933 and 1989.

Changes in rangeland vegetation integrate the consequences of livestock grazing intensity and possible climate change, as well as other factors. Because vegetation changes tend to be very slow in dry environments, observational time scales that exceed a human generation are needed to separate real trends from year-to-year, weather-driven variability. An exhaustive literature search for valid starting points within the Intermountain region revealed a unique quantitative study that was more than 50 years old. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah, was read from 19-m2 plots located every 42 m. The only intentional, local management treatment in the interim has been moderation of domestic livestock grazing pressure. During a period climatically and phenologically similar to the original study, we re-examined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. We found that vegetation type boundaries and ecotones were little changed after 56 years. However, canopy cover was dramatically greater in 1989, in some cases by more than tenfold for several perennial grasses, and less so for shrubs. Substantially greater understory cover as a relative proportion of total plant cover occurred in 1989 in all vegetation types examined. Some of the observed positive shifts of dominance/diversity are contrary to widely accepted expectations in the literature

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

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

Vegetation differences in desert shrublands of western Utah's Pine Valley between 1933 and 1989

Changes in rangeland vegetation integrate the consequences of livestock grazing intensity and possible climate change, as well as other factors. Because vegetation changes tend to be very slow in dry environments, observational time scales that exceed a human generation are needed to separate real trends from year-to-year, weather-driven variability. An exhaustive literature search for valid starting points within the Intermountain region revealed a unique quantitative study that was more than 50 years old. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah, was read from 19-m2 plots located every 42 m. The only intentional, local management treatment in the interim has been moderation of domestic livestock grazing pressure. During a period climatically and phenologically similar to the original study, we re-examined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. We found that vegetation type boundaries and ecotones were little changed after 56 years. However, canopy cover was dramatically greater in 1989, in some cases by more than tenfold for several perennial grasses, and less so for shrubs. Substantially greater understory cover as a relative proportion of total plant cover occurred in 1989 in all vegetation types examined. Some of the observed positive shifts of dominance/diversity are contrary to widely accepted expectations in the literature.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

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

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.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Vegetation Differences in Desert Shrublands of Western Utah\u27s Pine Valley Between 1933 and 1989

Changes in rangeland vegetation integrate the consequences of livestock grazing intensity and possible climate change, as well as other factors. Because vegetation changes tend to be very slow in dry environments, observational time scales that exceed a human generation are needed to separate real trends from year-to-year, weather-driven variability. An exhaustive literature search for valid starting points within the Intermountain region revealed a unique quantitative study that was more than 50 years old. In 1933, vegetation along a 37-km transect in southern Pine Valley, Utah, was read from 19-m2 plots located every 42 m. The only intentional, local management treatment in the interim has been moderation of domestic livestock grazing pressure. During a period climatically and phenologically similar to the original study, we re-examined representative segments of this transect by a more detailed updating of the original "square-foot-density" method. We found that vegetation type boundaries and ecotones were little changed after 56 years. However, canopy cover was dramatically greater in 1989, in some cases by more than tenfold for several perennial grasses, and less so for shrubs. Substantially greater understory cover as a relative proportion of total plant cover occurred in 1989 in all vegetation types examined. Some of the observed positive shifts of dominance/diversity are contrary to widely accepted expectations in the literature.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202