PARENT SESSION
Oral Session #48: Vegetation Change and Response.
Presiding: D. Zobel
Tuesday, August 6. 1:00 PM to 4:45 PM. Mesquite Room, Radisson.

A Landscape approach to aspen restoration: the Role of biophysical setting in aspen community dynamics.

Brown, Kathryn^*,1, Hansen, Andrew¹, ¹ Montana State University, Bozeman, MT

ABSTRACT- Aspen communities are critically important for maintaining biodiversity, soil quality, fire breaks, scenic beauty and nutrient cycling. Widespread and rapid loss of aspen in the western U.S. has been attributed to fire suppression, ungulate herbivory and climatic change. Restoration programs often focus on the use of prescribed fire or exclosures to promote aspen regeneration. The success of these efforts is often variable and is likely to relate to the area's capacity to sustain aspen. We hypothesize that the response of aspen to fire, conifer encroachment, and herbivory is strongly mediated by factors such as topography, climate and soils. We examine the distribution of aspen in the Greater Yellowstone Ecosystem relative to these physical variables through classification and regression tree (CART) analysis. We analyze aspen growth rates and primary productivity relative to topography, climate, soils, and biomass of competing vegetation through multiple regression. Aspen distribution in the GYE is shown to be strongly related to topography and soils. Within its distribution in the GYE, high aspen growth rates correlate with lower elevations, catchment areas, sedimentary-derived soils, and more mesic environments. These favorable landscape settings represent high priority places to focus restoration efforts where aspen can best respond to fire and tolerate herbivory.

KEY WORDS: aspen, restoration, biodiversity