LTER: Long-term research on the dynamics of high-elevation ecosystems -- a framework for understanding ecological responsiveness to climate change

尼沃特山脉/绿色湖谷(NWT)长期生态研究(LTER)是一项跨学科研究计划，其长期目标是更好地了解高山山脉内的生态系统，并促进生态学知识的全面发展。虽然世界上20%的人口生活在以积雪或冰川融化的水为水源的河流流域，但我们对高山地区积雪和温度的变化将如何影响生物多样性保护或水资源管理知之甚少。生态系统对气温升高的反应需要很多年到几十年的时间，因此需要长期的观察和长期的实验来检测和理解这些反应。西北地区LTER研究为区域、国家和全球网络测量高海拔地区水循环和生活的变化提供了重要的参考点。与西北部地区有关的山地提供了一个天然实验室，用于探索为什么有些栖息地可能对环境变化非常敏感，而另一些地区则可能不敏感。西北大学的自然环境还提供了许多特征，有助于促进和培养人们对科学和自然的兴趣，并激励学生和公众了解山脉和隧道的生态。西北大学LTER项目建立在超过35年的长期测量和实验的基础上，以更好地了解气候变化在何时何地导致生态变化，并阐明导致生态系统响应或稳定的机制。具体目标包括：(A)利用长期观测来确定高山环境如何对气候作出反应；(B)利用长期实验来检验关于基本驱动因素的假设以及这些反应之间的整合；以及(C)将这些信息纳入建模框架，以完善对未来变化的理解和预测反应。这项研究在概念上是围绕气候变化如何转化为跨越空间复杂景观和跨生态组织水平的生态反应来组织的。提出的问题源于关于复杂地形中的气候暴露和补偿动力学的理论，西北大学的长期观测和跨学科专业知识允许对这些理论进行全面测试。具体的调查是以西北地区气候长期趋势的生态反应的巨大变化为框架的，这些趋势包括春季和夏季气温变暖、更早的积雪融化和湖泊结冰以及更长的生长季。研究将集中在林线和亚高山森林，高山和亚高山湖泊，以及高山冻原生态系统。外联和培训面向广泛的受众，包括K-12学生、普通公众和公民科学家，同时强调对研究生进行科学交流和参与学术方面的培训。

The Niwot Ridge/Green Lakes Valley (NWT) Long Term Ecological Research (LTER) is an interdisciplinary research program with the long-term goals of better understanding ecosystems within high mountain ranges and contributing to a general advance of knowledge in ecology. While twenty percent of the world population lives in river basins fed by melt waters from snow or glaciers, we know very little about how changes in snowpack and temperature in high mountain areas will affect biodiversity conservation or the management of water resources. Ecosystem responses to increasing temperature occur over many years to many decades, so long-term observations and long-term experiments are required to detect and understand those responses. The NWT LTER research provides an important reference point for regional, national, and global networks to measure changes in the water cycle and life at high elevations. The mountainous lands associated with NWT provides a natural laboratory in which to explore why some habitats may be very sensitive to changes in the environment while other areas may not be sensitive. The natural setting of NWT also provides many features that can help promote and develop an interest in science and nature, and inspire schoolchildren and the public to learn about the ecology of mountains and the tundra.The NWT LTER program builds on over 35 years of long-term measurements and experiments to better understand where and when climate change results in ecological change, and to elucidate the mechanisms that lead to responsiveness or stability in ecological systems. Specific objectives include (a) using long-term observations to characterize how high-mountain environments are responding to climate, (b) using long-term experiments to test hypotheses about the underlying drivers and integration among these responses, and (c) integrating this information in modeling frameworks to both refine understanding and forecast responses to future change. The research is conceptually organized around how climate change translates to ecological response across a spatially complex landscape and across ecological levels of organization. Proposed questions derive from theory on climate exposure in complex terrain and compensatory dynamics, and the long-term observations and interdisciplinary expertise at NWT allow comprehensive tests of these theories. Specific investigations are framed by substantial variation in ecological responses to long-term trends in climate at NWT involving warmer spring and summer temperatures, earlier snowmelt and lake ice-off, and longer growing seasons. Research will focus on treeline and subalpine forest, and alpine and subalpine lakes, and alpine tundra ecosystems. Outreach and training addresses a broad range of audiences, including K-12 students, the general public, and citizen scientists, while emphasizing training of graduate students in science communication and engaged scholarship.