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.

北极生态系统正在因北极变暖而发生变化，其变化速度是全球平均水平的两倍多。国际苔原实验 (ITEX) 成立于 20 世纪 90 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 项目对于检测苔原植物和生态系统对实验性变暖和跨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站网络 (AON)。 当前的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根据变暖来确定观察到的变化的原因，而不是依赖于简单的相关性。 该项目提供了有关植被变化的迫切需要的数据，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。 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 CLEO 研究所的牢固关系开展的外展活动；大谷州立大学地区数学和科学中心；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。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长期 ITEX 控制和实验变暖地块上的物候、植被结构和组成以及生态系统功能（碳通量和养分循环）的手动观测、长期 1 km2 植被网格上植被地块的重复测量以及多因素变暖/湿度 格陵兰岛的实验。 2009 年，抽样方案得到扩展，纳入了更大的空间成分，以放大所收集测量值的价值。此次扩展包括增加 Phenocam、自动化移动传感器平台和中型航空图像。自动化平台以几乎每天的频率，以最小的努力跨越跨越强湿度和微地形梯度的焦点横断面来测量一系列植被表面特性。这些测量捕获了生长季节植被的精细变化，而低频手动测量会错过这些变化，并在手动测量和航空图像之间架起一座桥梁。使用风筝航空或无人机在整个生长季节获取中等规模的航空图像，以缩放手动和自动测量；卫星图像参考中等规模的航空图像，以帮助将应对措施扩大到区域一级。在 AON ITEX 的最新阶段，我们特别关注了解永久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重大的正反馈。