To evaluate long-term range conditions in southern Utah, 1,879 repeat photographs were made on the Dixie and Fishlake National Forests, and adjoining lower elevation BLM and private lands. Repeat photographs were also made in Zion National Park, Cedar Breaks National Monument, and Bryce Canyon National Park where livestock grazing has been prohibited for many years. Of the total, 926 photo-pairs depict sagebrush (Artemisia spp.) communities and 471 depict mountain brush associations (Cercocaprus ledifolius, C. mountanus, Amelamchier utahensis, Quercus gambelii, Prunus virginiana). Sagebrush decreased in 261 photosets, increased in 386 and remained unchanged in 279, while mountain brush decreased in 10 photopairs, increased in 440, and showed no change in 21. Sagebrush increased on all sites that had been treated and planted to crested wheatgrass (Agropyron desertorum) during the 1950s to 1960s. Most of the decline in sagebrush was due to invasion by pinyon (Pinus spp.) and/or juniper (Juniperus spp.), while an absence of fire is the most likely reason mountain brush increased. The observed changes have major implications for wildlife, and especially mule deer (Odocoileus hemionus) where sagebrush winter ranges have been lost or where mountain brush has grown beyond the reach of browsing animals. All repeat-photosets and descriptive text have been placed on Utah State University’s Extension website and can be accessed at http://extension.usu.edu.rra.
Kay, Charles E. and Reid, Chad R.
"Long-Term Changes in Southern Utah Upland Shrub Communities: A Study in Repeat Photography,"
Natural Resources and Environmental Issues: Vol. 16
, Article 31.
Available at: https://digitalcommons.usu.edu/nrei/vol16/iss1/31