Shrub Seedling Experiment: Environmental Conditions, Vegetation Composition, and Seedling Recruitment, Seward Peninsula, Alaska, 2018-2019

In June 2018, a manipulative seed-addition experiment was established at the Council Mile Marker 71 (CN_MM71), Quartz Creek Burn Area (Kougarok Mile Marker 86), and Quartz Creek Unburned (Kougarok Mile Marker 80) sites on the Seward Peninsula, Alaska. At each site, 5 replicate blocks were established in disturbed and intact upland tussock tundra (a total of 40 plots). Disturbed plots at Council were located on thermo-erosional (thermokarst) slopes, while disturbed plots in Quartz Creek were in burned areas affected by the Mingvk Lake fire in 2015. Using a split-plot design, an additional manual disturbance treatment (scraping to remove the surface bryophyte layer) was implemented across all blocks in June 2018. Seeds of five erect, deciduous shrubs were broadcast seeded into each plot in June 2018, and seedlings were censused in August 2018 and August 2019. The dataset includes ancillary measurements of plot-level environmental conditions (soil temperature, moisture, chemistry, thaw depth, microtopography, substrate thickness) and vegetation composition (NDVI and estimated percent cover by species and plant functional type). Dataset contains 10 csv data files (five data files with corresponding data dictionaries and one file-level metadata file) and one pdf user guide. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

2018年6月，于阿拉斯加苏厄德半岛的理事会里程碑71号（CN_MM71）、石英溪火烧区（库加尔鲁克里程碑86号）以及石英溪未火烧区（库加尔鲁克里程碑80号）样地，设立了控制性种子添加实验。每个样地均在受干扰与完整的高地丛状苔原中设置5个重复样区，总计40个样方。其中，理事会样地的受干扰样方位于热侵蚀（热喀斯特）斜坡，石英溪样地的受干扰样方则处于2015年明夫克湖火灾波及的火烧区域。2018年6月，采用裂区设计对所有样区施加额外人工干扰处理（刮除地表苔藓层）。同年6月，向每个样方撒播5种直立落叶灌木的种子，并分别于2018年8月与2019年8月对幼苗进行普查。
本数据集包含样方级环境条件（土壤温度、土壤湿度、土壤化学性质、解冻深度、微地形、基质厚度）与植被组成（归一化植被指数（Normalized Difference Vegetation Index, NDVI），以及物种和植物功能型的预估盖度百分比）的辅助测量数据。数据集内含10个CSV数据文件（其中5个数据文件配有对应的数据字典，外加1个文件级元数据文件）与1份PDF用户指南。
下一代北极生态系统实验（Next-Generation Ecosystem Experiments: Arctic, NGEE Arctic）是一项旨在通过构建富碳北极生态系统的预测性认知及其对气候的反馈机制，降低地球系统模型不确定性的研究项目。该项目由美国能源部生物与环境研究办公室资助。NGEE Arctic设有两个野外研究站点：1）位于阿拉斯加乌特恰维克（巴罗）附近北坡的巴罗环境观测站（BEO）内的北极多边形苔原沿海区域；2）阿拉斯加诺姆以北苏厄德半岛不连续永久冻土区的多个区域。通过观测、实验以及与现有数据集的综合分析，NGEE Arctic为多尺度建模提供了更完善的知识库，并助力美国能源部地球系统模型——能源极端尺度地球系统模型（Energy Exascale Earth System Model, E3SM），尤其是其E3SM陆面模型组件（ELM）在全球泛北极尺度上优化过程表征。