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。自1993年以来，麦克默多长期生态研究（LTER）项目一直在观察这些生态系统，该奖项将支持关键的长期测量，操作实验，合成和建模，以测试当前生态系统结构和功能的理论。 数据收集的重点是气象学以及土壤、溪流、湖泊、冰川和永久冻土的物理和生物方面。长期的测量表明，生物群落已经适应了季节性的寒冷，黑暗和干旱的条件下，占主导地位的所有，但在南方的夏季短时间。物理（气候和地质）驱动因素在季节到千年的时间尺度上赋予干谷景观部分之间的动态连接性。例如，湖泊和土壤在过去20 000年中通过湖泊水位上升和下降的周期连接在一起，而河流在季节性时间尺度上将冰川连接到湖泊。覆盖在这一物理系统之上的是生物群落，这些生物群落是由环境以及冰川、溪流、湖泊和土壤内部和之间的单个生物体的运动构成的。 在麦克默多LTER站点进行的新工作将探索麦克默多干谷的连通性层如何影响生态系统结构和功能。 该项目将测试以下假设：在麦克默多干谷生态系统内融化条件增强后，生态连通性的增加将扩大生物群、能量和物质的交换，增强生态系统的结构和功能。这一假设将通过新的和持续的实验进行测试，这些实验将研究：1）气候变化如何改变景观单元之间的连通性，以及2）生物群如何使用最先进的科学工具和方法，包括自动传感器网络，季节性卫星图像分析，地球化学分析和下一代测序，在异质景观中连接。麦克默多LTER教育方案和外展活动将继续下去，并将扩大与南极洲首次有记录目击200周年有关的新方案。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。麦克默多LTER将继续其使命，培训和指导学生，博士后和早期职业科学家作为极地生态系统科学的下一代领导者，并领导该地区人类活动的国际环境管理协议的制定。

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.