Plant community dynamics of burned and unburned sagebrush and pinyon-juniper vegetation in West-Central Utah

Abstract

Fire ecology of sagebrush and pinyon-juniper vegetation in the Great Basin has been influenced by human disturbances and exotic plant introductions. Late-seral woody vegetation, which increased following Euro-American settlement, is now decreasing because of wildfire and exotic annuals. Multiple successional pathways following fire have been observed in these vegetation types. Following the 1996 wildfires in west-central Utah, burned and unburned vegetation were compared at four sites. Measures of frequency, cover, and density of vascular plant species were used to show fire effects and to follow population dynamics over a period of 3 years. Woody species characteristic of the unburned areas were generally absent from the burned areas. Native herbaceous species, particularly annual forbs, were abundant in the burned areas 1 year after the fires, but many of these declined by the second and third year, as exotic species, particularly cheatgrass (Bromus tectorum), increased. Cheatgrass became dominant in the interspaces among burned trees by the second year following the fires, a period of high precipitation. In the subcanopy zones of burned trees, cheatgrass did not become dominant until the third year following the fire, and was preceded by exotic annual forbs. Community composition and structure differed by site as well as by fire history. Cheatgrass cover was lowest at a site where perennial grasses and forbs had become established through aerial broadcast seeding.

Parent Publication

• Shrubland ecosystem genetics and biodiversity: proceedings

Citation

Ott, Jeffrey E.; McArthur, E. Durant; Sanderson, Stewart C. 2001. Plant community dynamics of burned and unburned sagebrush and pinyon-juniper vegetation in West-Central Utah. In: McArthur, E. Durant; Fairbanks, Daniel J., comps. Shrubland ecosystem genetics and biodiversity: proceedings; 2000 June 13-15; Provo, UT. Proc. RMRS-P-21. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 177-191.