LTER: The Arctic LTER Project: The Future Characteristics of Arctic Communities, Ecosystems, and Landscapes

北极LTER地点位于阿拉斯加州布鲁克斯山脉的北麓，在苔原植被中，莎草和草混合着矮桦树和低矮的柳树。该遗址的冻土带、溪流和湖泊5000多年来一直没有受到干扰和变化。这使得能够分析这个生态系统中动植物之间的关系，这个生态系统不受人类使用的生态遗产的影响。与这种生态稳定性形成对比的是，阿拉斯加北部的气候在过去30年里发生了显著变化。该地区的气温每十年上升超过0.5摄氏度。没有人知道这种变暖是否是GCM模型预测的3-5度变化的一部分，但我们知道北极的其他地区要么没有变化，要么变得更冷了。根据几种类型的观察，似乎对这种区域变暖做出了生物反应。该LTER项目的目标是预测该地点未来的生态特征。这一预测是基于对自然环境和地质因素、气候因素、生物因素以及水和物质从陆地到水的通量变化对生态系统结构和功能的控制的知识。长期研究基于以下方法：(1)生态系统特征在空间和时间上的自然变化的长期监测和调查。这将包括对变量的常规监测，如气候、冻土带植物群落和生产力、融化深度、溪流流量、溪流化学、湖泊温度、湖泊化学、湖泊生产力以及浮游动物和鱼类的丰富程度。(2)与Bonanza Creek LTER计划合作的南北区域样带。(3)维护和测量了几十年的生态系统的实验操作。这些实验包括冻土带变暖、遮蔽和施肥、排除大型食草动物、给湖泊和溪流施肥，以及增加和移除捕食者。(4)综合和建模工作。总体而言，这项研究将增加我们对生态系统对人类引发的全球环境变化的反应的基本理解。此外，这些分析将有助于生态学中的理论问题，包括与干扰、资源可获得性、自上而下与自下而上对群落的控制以及生态系统结构和功能有关的问题。

9810222HobbieThe Arctic LTER site is located in the northern foothills of the Brooks Range, Alaska, in tundra vegetation of sedges and grasses mixed with dwarf birch and low willows. The tundra, streams and lakes at the site have been undisturbed and unchanged for more than 5,000 years. This allows the analysis of relationships among plants and animals in this ecosystem which is unaffected by an ecological legacy of human use. In contrast to this ecological stability, the climate of northern Alaska has changed remarkablyover the past 30 years. The temperature of the region has increased by more than 0.5oC per decade. No one knows if this warming is a part of the 3-5 degree change predicted by GCM models but it is known that other areas of the Arctic have either not changed or have become colder. Based on several types of observations, there appears to be a biotic response to this regional warming. The goal of this LTER project is to predict the future ecological characteristics of the site. This prediction is based on knowledge of the controls of ecosystem structure and function as exerted by physical setting and geologic factors, climatic factors, biotic factors, and the changes in fluxes of water and materials from land to water. The long-term research is based on the following approaches: (1) Long-term monitoring and surveys of natural variation of ecosystem characteristics in space and time. This will include routine monitoring of variables, such as climate, tundra plant communities and productivity, thaw depth, stream flow, stream chemistry, lake temperatures, lake chemistry, lake productivity and the abundance of zooplankton and fish. (2) A north-south regional transect in cooperation with the Bonanza Creek LTER program. (3) Experimental manipulations of ecosystems which are maintained and measured for decades. These experiments include tundra warming, shading and fertilizing, the exclusion of large herbivores, fertilization of lakes and streams, and the addition and removal of predators. (4) Synthesis and modeling efforts. Overall, this research will add to our basic understanding of the response of ecosystems to human induced global environmental change. In addition, these analyses will contribute to theoretical questions in ecology, including issues related to disturbances, resource availability, top-down vs. bottom-up controls on communities, and ecosystem structure and function.