DISSERTATION RESEARCH: Environmental Determinants of Subalpine Forest-grassland Ecotones in the Southern Rocky Mountains

本研究旨在区分气候因素和土壤性质在决定美国西南部山区亚高山草甸边界树木和草地物种竞争结果中的相对作用。研究人员将沿着自然环境梯度进行观察研究，并将进行实地试验，以区分冷空气排水与土壤肥力对树苗生存和与草竞争的影响。他们还将开发景观动态的历史重建，以补充梯度和实验研究。该项目的结果可以帮助解释与土地利用实践和气候有关的树木线（草地-林地边界）迁移的历史趋势。

This study is designed to distinguish the relative roles of climatic factors and soil properties in determining the outcome of competition among tree and grassland species at the borders of subalpine meadows in mountain regions of the southwestern US. The investigators will conduct observational studies along natural environmental gradients and will perform field experiments to distinguish the effects of cold air drainage vs. soil fertility on tree seedling survival and competition with grasses. They will also develop historical reconstructions of landscape dynamics to complement the gradient and experimental studies. The project results could help to explain historical trends in tree-line (grassland-woodland boundaries) migration in relation to land use practices and climate.