Brigham Young University Science Bulletin, Biological Series


Historical information, survey records, and relict vegetation were used as sources of data for determining the nature of the presettlement vegetation of Pavant, Round, and Juab Valleys in central Utah. The foothills were covered with bunch grasses (principally Agropyron spicatum and Poa secunda), scattered junipers (Juniperus utahensis), and sagebrush (Artemisia tridentate). Western wheatgrass (Agropyron smithii) was common on level areas within the foothills. Below the foothill region on the more gentle slopes and benchlands there was a broad belt dominated by bunch grasses. The grassy area intergraded into a zone dominated by northern desert shrubs, particularly sagebrush, (grasses were conspicuous also in the northern desert shrub zone. In the valley bottoms, wet meadows and salt desert shrub communities occurred.

Significant changes in the presettlement vegetation had occurred by 1900. In general, there was a transition from a predominance of perennial grasses to one of sagebrush throughout the foothills and benchlands, and grasses became less abundant in the shrub communities. After 1870 juniper increased in density and invaded areas that were formerly dominated by grasses. These changes accompanied the use of these areas as range lands for livestock. In this century several exotic species have become important components of the vegetation.

The rates of migration since 1870 of two groups of unstable sand dunes in Pavant Valley were determined to be 53.5 and 60.9 feet per year.