Responses of Arctic Tundra to Experimental and Observed Changes in Climate

作者：F. Stuart Chapin, Gaius R. Shaver, Anne E. Giblin, Knute J. Nadelhoffer, James A. Laundre · 发表于：Ecology · 年份：1995 · DOI：10.2307/1939337 · 被引用次数：1442 · 研究领域：Climate change and permafrost、Geology and Paleoclimatology Research、Polar Research and Ecology

We manipulated light, temperature, and nutrients in moist tussock tundra near Toolik Lake, Alaska to determine how global changes in these parameters might affect community and ecosystem processes. Some of these manipulations altered nutrient availability, growth—form composition, net primary production, and species richness in less than a decade, indicating that arctic vegetation at this site is sensitive to climatic change. In general, short—term (3—yr) responses were poor predictors of longer term (9—yr) changes in community composition. The longer term responses showed closer correspondence to patterns of vegetation distribution along environmental gradients. Nitrogen and phosphorus availability tended to increase in response to elevated temperature, reflecting increased mineralization, and in response to light attenuation, reflecting reduced nutrient uptake by vegetation. Nutrient addition increased biomass and production of deciduous shrubs but reduced growth of evergreen shrubs and nonvascular plants. Light attenuation reduced biomass of all growth forms. Elevated temperature enhanced shrub production but reduced production of nonvascular plants. These contrasting responses to temperature increase and to nutrient addition by different growth forms "canceled out" at the ecosystem level, buffering changes in ecosystem characteristics such as biomass, production, and nutrient uptake. The major effect of elevated temperature was to speed plant response to changes in soil r...