Arctic Observing Networks: Collaborative Research:ITEX AON - understanding the relationships between vegetation change, plant phenology, and ecosystem function in a warming Arctic

北极观测网络：合作研究：ITEX AON - 了解北极变暖中植被变化、植物物候和生态系统功能之间的关系

• 批准号: 1504345
• 负责人: Craig Tweedie
• 金额: $ 28.14万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-15 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1504345&HistoricalAwards=false
• 关键词: Arctic; Observing; Networks; Collaborative; Research

Arctic ecosystems are changing in response to arctic warming, which is proceeding more than twice as fast as the global average. The International Tundra Experiment (ITEX) was established in the early 1990s to understand the effects of warming and environmental variability on tundra vegetation properties and ecosystem function. The ITEX program has been extremely valuable for detection of changes in tundra plant and ecosystem responses to experimental warming and to background climate change across sites that span the major ecosystems of the Arctic. In 2007, the Alaskan and Greenland ITEX sites were combined into an Arctic Observatory Network (AON). The current ITEX AON project will continue to document and understand Arctic terrestrial vegetation change and its ecosystem consequences by maintaining the long-term datasets of the ITEX-AON. The warming experiment of ITEX-AON allows us to assign the cause for observed changes in response to warming instead of relying on simple correlations. This project provides urgently needed data on changes in vegetation and the importance of these changes for ecosystem services from a variety of Arctic ecosystems. This project will provide training for postdoctoral, graduate and undergraduate students in the emerging fields of remote sensing, cybertechnology and big-data analysis. The project will include outreach activities through strong relationships with the CLEO Institute in Miami; the Grand Valley State University Regional Math and Science Center; and K-12 school systems in Miami, Anchorage, Grand Rapids and El Paso. All data from this project are and will be freely available at the NSF Arctic Data Center.The core datasets of the proposed research include manual observations of phenology, vegetation structure and composition, and ecosystem function (carbon flux and nutrient cycling) on long-term ITEX control and experimental warming plots, repeat measurement of vegetation plots on the long-term 1 km2 vegetation grids, and a multifactor warming/moisture experiment in Greenland. In 2009, the sampling scheme was expanded to include a larger spatial component to amplify the value of the measurements collected. This expansion included the addition of phenocams, automated mobile sensor platforms, and medium-scale aerial imagery. The automated platforms measure a suite of vegetation surface properties with minimal effort across focal transects spanning strong moisture and microtopographic gradients at a near-daily frequency. These measurements capture the fine-scale changes in vegetation over the growing season that are missed by lower frequency manual measurements and provide a bridge between manual measurements and aerial imagery. Medium-scale aerial imagery, using Kite Aerial or Unmanned Aerial Vehicles, is acquired throughout the growing season for scaling of manual and automated measurements; satellite imagery is referenced to medium-scale aerial imagery to aid scaling of responses to the regional level. In the newest phase of AON ITEX, we are particularly focused on understanding the relationship between landscape subsidence as a result of permafrost thaw and vegetation structure and function because of the potential for significant positive feedbacks to climate change.

北极生态系统正在发生变化，以应对北极变暖，其速度是全球平均速度的两倍多。国际苔原实验（ITEX）成立于1990年代初，旨在了解变暖和环境变化对苔原植被特性和生态系统功能的影响。 ITEX计划对于检测冻土带植物和生态系统对实验性变暖和跨越北极主要生态系统的背景气候变化的反应变化非常有价值。 2007年，阿拉斯加和格陵兰ITEX站点合并为北极观测网（AON）。 目前的ITEX AON项目将通过维护ITEX AON的长期数据集，继续记录和了解北极陆地植被变化及其生态系统后果。 ITEX-AON的变暖实验使我们能够为观测到的变暖变化分配原因，而不是依赖于简单的相关性。 该项目提供了关于植被变化以及这些变化对各种北极生态系统的生态系统服务的重要性的迫切需要的数据。 该项目将为遥感、网络技术和大数据分析等新兴领域的博士后、研究生和本科生提供培训。该项目将包括通过与迈阿密的CLEO研究所、大峡谷州立大学区域数学和科学中心以及迈阿密、安克雷奇、大急流城和埃尔帕索的K-12学校系统建立强有力的关系开展外联活动。该项目的所有数据都将在NSF北极数据中心免费提供。拟议研究的核心数据集包括人工观测的物候、植被结构和组成以及生态系统功能（碳通量和养分循环），在长期ITEX控制和实验变暖地块，重复测量植被地块的长期1平方公里的植被网格，和格陵兰岛的多因素变暖/湿度实验。2009年，扩大了抽样计划，纳入了更大的空间组成部分，以扩大所收集的测量值。这种扩展包括增加phenocams，自动移动的传感器平台和中等规模的航空成像。自动化平台以几乎每天的频率测量一套植被表面特性，以最小的努力跨越强水分和微地形梯度的焦点断面。这些测量捕捉到生长季节植被的细微变化，这些变化是较低频率的人工测量所遗漏的，并在人工测量和航空图像之间架起了一座桥梁。在整个生长季节使用风筝航拍器或无人驾驶飞行器获取中等比例尺航拍图像，用于人工和自动测量的缩放;卫星图像参照中等比例尺航拍图像，以帮助缩放区域一级的应对措施。在AON ITEX的最新阶段，我们特别关注了解冻土融化导致的景观沉降与植被结构和功能之间的关系，因为这可能对气候变化产生显著的正反馈。