Document Type

Greater Yellowstone Ecosystem Report

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The aim of this study is to better understand the relationship of biotic and abiotic variables to the distribution, performance, and rates of loss of aspen in the Greater Yellowstone Ecosystem. Aspen commumtles, though critically important for maintaining biodiversity, soil quality, and nutrient cycling, are declining rapidly in the Northern Rockies. Fire suppression, elk browsing, and climatic change are the most widely advanced explanations for this widespread loss of aspen. The role of biophysical factors (e.g. topography, climate, soils, and competing vegetation) in determining aspen performance, however, is poorly understood. Knowledge of these relationships may provide a basis for tailoring aspen restoration efforts to specific landscape settings. To better understand the influence of biophysical variables on aspen dynamics, this study addresses three hypotheses: 1. The aerial distribution of aspen is not random across the landscape and varies as a function of biophysical setting. 2. Within its distribution, growth rates and productivity of aspen stands differ relative to biotic and abiotic variables. 3. Rates of aspen loss in the landscape differ relative to biophysical setting. Here we report progress on the first year of the two-year study.