DISSERTATION RESEARCH: Impacts of global warming at high elevation tree lines in the Himalayas

人为气候变化导致的气温上升在高海拔地区尤为明显，威胁到许多物种的生存。该项目将研究尼泊尔喜马拉雅地区相对原始的森林中，海拔4000米左右的树木海拔上限如何响应气候变化。初步研究表明，优势树种杜鹃花（Rhododendron）的海拔边界正在迅速向上移动，海拔最高的个体比海拔低150 m的个体更能适应极端气候条件，但对竞争的耐受性较差。该项目将扩展这项工作，包括对个体和地点之间差异的额外测量，这些差异在地形和降雨量等关键特征上存在差异。结果将有助于揭示山地物种如何对气候变化做出反应，这些反应如何取决于物种之间的相互作用或具体地点，以及哪些机制驱动了高海拔地区范围的变化，并确定了当地灭绝的相关风险。该项目将训练学生实地方法，并为他们提供探索远离城市的自然地区的机会。此外，该项目将在德克萨斯大学、特里布万大学和尼泊尔科学技术学院的研究人员之间形成一个新的国际合作。联合项目负责人将向加德满都的本科生和研究生讲授生态学、气候变化研究和高级统计工具的当前趋势的短期课程。将在朱姆拉和加德满都向公众进行外联演讲，以提高他们对气候变化及其对他们生活的影响的认识。

Temperature rise from anthropogenic climate change is often especially pronounced at high elevations, where it threatens the survival of many species. This project will study how the upper elevational boundary of trees at about 4000 m is responding to climate change in relatively pristine forests of the Nepal Himalayas. Preliminary work suggests that the upper elevational boundary of one of the dominant trees, a species of Rhododendron, is rapidly shifting upward, with individuals at the highest elevations being more tolerant to extreme climate conditions but less tolerant of competition than individuals only 150 m lower. This project will expand this work to include additional measures of differences between individuals and sites that differ in key characteristics such as aspect and rainfall. Results will help show how montane species respond to climate change, how responses may depend upon interactions between species or site specifics, and which mechanisms drive shifts in range at high elevation and determine associated risks of local extinction. The project will train students in field methods and provide them with an opportunity to explore natural areas distant from cities. Additionally, the project will form a new international collaboration between researchers at the University of Texas and Tribhuvan University and the Nepal Academy of Science and Technology in Nepal. The co-PI will teach short courses to undergraduate and graduate students in Kathmandu on current trends in ecology, climate change research, and advanced statistical tools. Outreach presentations to the general public will be given in Jumla and Kathmandu to increase their awareness of climate change and its impacts on their lives.