DISSERTATION RESEARCH: Vegetation Feedbacks to Climate Change: Extending Results from an Ecosystem-Warming Experiment to Landscape Level

小行星9623258 植被对气候变化的反馈：将生态系统变暖实验的结果扩展到景观水平。对全球气候变化的预测所依据的模型在很大程度上忽略了气候-生态系统的相互作用。然而，这种相互作用可能会对气候产生巨大的积极或消极反馈。例如，植被覆盖的变化将改变与大气的能量和水分交换，可能是反馈的重要来源。为了量化这种反馈，需要对实验地块尺度上的气候-生态系统相互作用进行详细和机械的理解，沿着可靠的方法来概括从生态系统实验和自然气候梯度分析中获得的知识。该项目将联合收割机操作与高程样带研究相结合，以1）加深对形成气候-生态系统反馈的机制和偶然因素的理解，2）评估和改进样带和操作研究的使用，以外推生态系统响应和反馈到景观尺度的结果。重点将是在亚高山草甸栖息地在科罗拉多的优势植被从杂类草灌木的转变。这种生态系统对气候变化的反应是在四年的气候变暖实验模拟中观察到的。从监测植被和气候变量沿海拔梯度沿着的相关性将比较结果1）现有的和持续的气候操纵，2）额外的气候操纵和相互移植沿着梯度，和3）年际气候变化在每个数据集。

9623258 Harte Vegetation feedbacks to climate change: extending results from an ecosystem-warming experiment to landscape level. Predictions of global climate change are based on models that largely ignore climate-ecosystem interactions. Yet such interactions may potentially generate large positive or negative feedbacks to the climate. For example, shifts in vegetative cover will alter energy and water exchange with the atmosphere and could be a significant source of feedback To quantify such feedbacks, a detailed and mechanistic understanding of climate-ecosystem interactions on the scale of experimental plots is needed, along with reliable methods for generalizing knowledge obtained from ecosystem experimentation and natural climatic gradient analysis. This project will combine manipulations with elevational transect studies to 1) deepen understanding of mechanisms and contingent factors that shape climate-ecosystem feedbacks, and 2) evaluate and improve the use of transect and manipulation studies for extrapolating results about ecosystem response and feedback to the landscape scale. The focus will be on a shift in dominant vegetation from forbs to shrubs in subalpine meadow habitat in Colorado. This ecosystem response to climate variation has been observed over four years of an experimental simulation of climate warming. Correlations derived from monitoring vegetation and climatic variables along an elevational gradient will be compared with results from 1) the existing and continuing climate manipulation, 2) additional climate manipulations and reciprocal transplants along the gradient, and 3) interannual climatic variation within each data set.