LTER: Ecosystem Response to Amplified Landscape Connectivity in the McMurdo Dry Valleys, Antarctica

南极洲的麦克默多干谷是寒冷沙漠中陆地和水生生态系统的马赛克。麦克默多长期生态研究(LTER)项目自1993年以来一直在观察这些生态系统，该奖项将支持关键的长期测量、操纵实验、合成和建模，以测试当前关于生态系统结构和功能的理论。数据收集的重点是土壤、河流、湖泊、冰川和永久冻土的气象学和物理和生物维度。长期测量表明，生物群落已经适应了季节性寒冷、黑暗和干旱的条件，除了南半球夏季的一小段时间外，所有这些条件都很普遍。自然(气候和地质)驱动因素在季节性到千禧年的时间尺度上赋予了干旱山谷部分景观之间的动态连通性。例如，在过去的2万年里，湖泊和土壤通过湖泊水位的上升和下降循环连接在一起，而溪流在季节性时间尺度上将冰川和湖泊连接起来。覆盖在这个物理系统上的是生物群落，它们由环境以及冰川、溪流、湖泊和土壤内部和之间的单个有机体的运动构成。这项将在麦克默多LTER现场进行的新工作将探索麦克默多干旱山谷的连接层如何影响生态系统结构和功能。该项目将检验这样一种假设，即麦克默多干谷生态系统内的融化条件增强后，生态连通性增加将放大生物群、能量和物质的交换，使生态系统结构和功能同质化。这一假设将通过新的和持续的实验得到验证，这些实验检查：1)气候变化如何改变景观单元之间的连通性；2)生物群如何使用最先进的工具和方法在不同的景观中连接起来，包括自动传感器网络、季节性卫星图像分析、生物地球化学分析和下一代测序。McMurdo LTER教育方案和外联活动将继续进行，并将扩大与第一次有记录的南极目击事件200周年相关的新方案。这些活动将促进社会对极地生态系统如何应对变化的理解。McMurdo LTER将继续其培养和指导学生、博士后和早期职业科学家的使命，作为极地生态系统科学的下一代领导者，并领导为该地区的人类活动制定国际环境管理协议。

The McMurdo Dry Valleys, Antarctica, are a mosaic of terrestrial and aquatic ecosystems in a cold desert. The McMurdo Long Term Ecological Research (LTER) project has been observing these ecosystems since 1993 and this award will support key long-term measurements, manipulation experiments, synthesis, and modeling to test current theories on ecosystem structure and function. Data collection is focused on meteorology and physical and biological dimensions of soils, streams, lakes, glaciers, and permafrost. The long-term measurements show that biological communities have adapted to the seasonally cold, dark, and arid conditions that prevail for all but a short period in the austral summer. Physical (climate and geological) drivers impart a dynamic connectivity among portions of the Dry Valley landscape over seasonal to millennial time scales. For instance, lakes and soils have been connected through cycles of lake-level rise and fall over the past 20,000 years while streams connect glaciers to lakes over seasonal time scales. Overlaid upon this physical system are biotic communities that are structured by the environment and by the movement of individual organisms within and between the glaciers, streams, lakes, and soils. The new work to be conducted at the McMurdo LTER site will explore how the layers of connectivity in the McMurdo Dry Valleys influence ecosystem structure and function. This project will test the hypothesis that increased ecological connectivity following enhanced melt conditions within the McMurdo Dry Valleys ecosystem will amplify exchange of biota, energy, and matter, homogenizing ecosystem structure and functioning. This hypothesis will be tested with new and continuing experiments that examine: 1) how climate variation alters connectivity among landscape units, and 2) how biota are connected across a heterogeneous landscape using state-of-the-science tools and methods including automated sensor networks, analysis of seasonal satellite imagery, biogeochemical analyses, and next-generation sequencing. McMurdo LTER education programs and outreach activities will be continued, and expanded with new programs associated with the 200th anniversary of the first recorded sightings of Antarctica. These activities will advance societal understanding of how polar ecosystems respond to change. McMurdo LTER will continue its mission of training and mentoring students, postdocs, and early career scientists as the next generation of leaders in polar ecosystem science, and lead the development of international environmental stewardship protocols for human activities in the region.