LTER: Cross-scale controls over responses of the Alaskan boreal forest to changing disturbance regimes

在过去的一个世纪里，阿拉斯加变暖的速度是美国其他地区的两倍多，其中一些最大的增长发生在远离海岸的北方(松林)森林。这种变暖引发了野火的数量和规模、冻土融化、水流模式以及虫害和疾病的爆发等方面的巨大变化。因此，阿拉斯加的景观正在以复杂的方式迅速变化，这一点很重要，因为这些变化直接影响到阿拉斯加居民获得自然资源和生态系统服务。更广泛地说，远北地区景观的变化具有全球意义，因为北方森林覆盖了大片地区，并在决定地球气候方面发挥了作用。了解北方森林如何以及为什么会对变暖的世界做出反应，对于预测下个世纪的区域和全球变化非常重要。这项始于1987年的长期生态研究(LTER)项目将继续提供有关气候变化如何影响阿拉斯加森林和依赖森林为生的人们的长期数据。这项LTER研究将测试新的想法，并获得只有从持续数十年的研究中才可能获得的类型的新见解。LTER的科学家还将继续他们与州和联邦机构在森林和野生动物管理方面的长期合作，特别是在增加火灾干扰方面。该项目代表了一个综合研究计划，旨在研究阿拉斯加北部森林对气候-干扰相互作用变化的跨尺度控制，包括对气候系统区域反馈的相关后果，并与阿拉斯加农村社区和土地管理机构一起确定脆弱性和对社会生态变化的潜在适应。该项目通过整合五个组成部分来研究变化的动力学：1)通过表征对生态系统和干扰的空间异质性的控制以及这些控制对区域气候的敏感性，研究气候变化对生态系统和干扰制度的直接影响，并通过研究多个干扰的时空同步性来评估哪些景观最容易受到变化的影响；2)了解依赖尺度的气候-干扰相互作用的模式、机制和后果，包括作为生态系统和景观变化驱动因素的火、冻土和营养动态的当前和遗留影响；3)通过研究和模拟中尺度模式和过程如何影响区域尺度生态系统动态和气候反馈，将景观异质性与区域和全球气候反馈联系起来；4)研究气候多变性和变化如何影响耦合的社会-生态动态，方法是确定选定的一组阿拉斯加内陆社区生态系统服务变化的特点，并与社区合作，找到减少脆弱性和更好地适应社会-生态变化的解决方案；5)将科学和资源管理与区域环境变化结合起来，方法是与各机构协调研究活动，以填补管理知识空白，评估决策结果，并以有意义的方式向决策者传达综合信息。

Alaska has warmed more than twice as rapidly as the rest of the United States over the past century, with some of the largest increases occurring in boreal (pine) forests far from the coast. This warming has triggered large changes in the number and size of wildfires, the melting of frozen soil, patterns of water flow, and outbreaks of insects and diseases. Thus, Alaskan landscapes are changing rapidly in complex ways, which is important because the changes directly affect the availability of natural resources and ecosystem services to Alaskan residents. More generally, changes to landscapes in the far North are of global significance because boreal forests cover vast areas and play a role in determining the Earth's climate. Understanding how and why boreal forests respond as they do to a warmer world is important for predicting both regional and global changes over the next century. This Long Term Ecological Research (LTER) project, started in 1987, will continue to provide long-term data on how changing climate impacts Alaskan forests and the people who depend on them for a living. This LTER research will test new ideas and gain fresh insights of the type possible only from studies that last decades. The LTER scientists will also continue their long history of collaboration with state and federal agencies regarding forest and wildlife management, especially in regard to increasing disturbance from fire. This project represents an integrated research program to study the cross-scale controls over responses of the Alaskan boreal forest to changing climate-disturbance interactions, including the associated consequences for regional feedbacks to the climate system, and to identify vulnerabilities and potential adaptations to social-ecological change with rural Alaskan communities and land management agencies. The project addresses the dynamics of change through the integration of five components: 1) Studying direct effects of climate change on ecosystems and disturbance regimes by characterizing controls over the spatial heterogeneity of ecosystems and disturbances, and the sensitivities of these controls to regional climate, and by studying the spatial and temporal synchrony of multiple disturbances to assess which landscapes are most vulnerable to change; 2) Understanding patterns, mechanisms, and consequences for scale-dependent climate-disturbance interactions involving current and legacy influences of fire, permafrost, and trophic dynamics as drivers of ecosystem and landscape change; 3) Linking landscape heterogeneity with regional and global climate feedbacks by studying and modeling how intermediate-scale patterns and processes influence regional scale ecosystem dynamics and climate feedbacks; 4) Studying how climate variability and change are affecting coupled social-ecological dynamics by characterizing variability in changes to ecosystem services across a select group of interior Alaskan communities, and collaborating with communities to find solutions that reduce vulnerability and improve adaptation to social-ecological change; 5) Integrating science and resource management with regional environmental change by coordinating research activities with agencies to fill management knowledge gaps, assessing outcomes of policy decisions, and communicating syntheses to policy makers in meaningful ways.