Long-term Studies of Ecosystem Response to Disturbance Along Environmental Gradients at Coweeta Hydrologic Laboratory

该项目将继续对阿巴拉契亚南部森林生态系统对干扰的反应和恢复进行长期研究。要理解和预测对当前和新出现的环境问题的反应，需要将研究视角从一个分水岭扩展到一个景观。该项目将强调沿着复杂的环境梯度进行的新研究，并继续强调使用实验操作来检查生态系统对干扰的反应。这项研究将使用一个代表外部驱动变量(如温度、降水)的梯度和生态系统响应的梯度的海拔序列。三个相互关联的生态系统沿着这一响应梯度排列：森林覆盖的斜坡、河岸带和溪流。PIS将在这些景观组成部分中检验以下想法：(1)由于历史因素和最近干旱导致的树木死亡，阿巴拉契亚山脉南部的森林结构和进程目前正在发生变化。(2)河流生态系统的结构和功能特征沿海拔梯度和纵向梯度的差异是河流地貌斑块类型相对丰富度变化的结果。(3)高大杜鹃是阿巴拉契亚南部景观中的重要树种，它调节森林中可溶性元素和颗粒元素的输出速率，降低河流生产力。这是一个杰出的研究小组，在国家和国际一级被公认为森林生态系统研究领域的领导者。制度保障优良，项目管理动态化、实效化。二十多年来，考维塔水文实验室一直是跨学科生态研究的场所。这是一个特殊的长期生态研究(LTER)项目。

This project will continue long-term studies of response and recovery of Southern Appalachian forested ecosystems to disturbances. To understand and predict responses to current and emerging environmental problems requires an expansion of research perspective from a watershed to a landscape. The project will emphasize new studies along a complex environmental gradient with a continued emphasis on use of experimental manipulation to examine ecosystem response to disturbance. An elevational sequence that represents a gradient in external driving variables (e.g. temperature, precipitation) as well as a gradient in ecosystem response will be used in this study. Three interconnected ecosystems are arrayed along this response gradient: forested slopes, riparian zone and stream. The PIs will test the following ideas in these landscape components: (1) Forest structure and processes in the Southern Appalachians are currently changing as a result of both historic factors and recent drought-induced tree mortality. (2) Differences in structural and functional characteristics of stream ecosystems along elevational and longitudinal gradients are a consequence of changes in the relative abundance of geomorphic patch types along the stream. (3) Rhododendron maximum is a keystone species in the Southern Appalachian landscape, regulating the rates of soluble and particulate element export from the forest and reducing stream productivity. This is an outstanding research group that is recognized at the national and international level as leaders in the area of forest ecosystem research. Institutional support is excellent and the project management is dynamic and effect. Coweeta Hydrologic Laboratory has been the site of interdisciplinary ecological research for over twenty years. This is an exceptional Long-Term Ecological Research (LTER) project.//