Arthropod food webs in the foreland of a retreating Greenland glacier: Integrating molecular gut content analysis with Structural Equation Modelling

Combining DNA gut content analysis with Structural Equation Modelling (SEM) based on arthropod activity density at a Greenland glacier foreland give us the opportunity to combine qualitative data from the metabarcoding technique with an analysis technique based on quantitative data. SEM shows bottom-up and top-down controlled food chains as bottom-up control was important for spider and harvestman populations while top-down control was important for ground beetle populations. These mechanisms are closely related to the hunting strategies of the predators as bottom-up mechanisms are connected to a sit-and-wait behavior while top-down mechanisms are related to active-search behavior. Bottom-up controlled population developments were important in the early phase of the vegetation development while top-down prevailed in the later phase of the vegetation development away from the glacier snout. The shift from bottom-up to top-down cascades between arthropod predators and their potential prey..., Data was collected using wet pitfall traps set up across various patches in the glacier foreland areas during the summers of 2015 and 2016. Soil samples were also taken for environmental characterization. Captured arthropods were identified to species or family level. Soil samples were analyzed for water and organic matter content. The activity density of arthropods was measured based on pitfall trap catches, and environmental variables were correlated with arthropod population data. NDVI measurements were used to assess vegetation biomass. Qassinnguit Dates and Sampling Information: Soil samples were taken at the Qassinnguit glacier foreland on August 7, 2015, and August 5, 2016, to measure the environmental variables of soil water and organic matter during dry weather periods. NDVI scanning was performed on August 1, 2016. Wet pitfall traps for sampling arthropods were established on July 8, 2015, with continuous sampling until August 7, 2015, when sampling was postponed until August ..., , # Arthropod food webs in the foreland of a retreating Greenland glacier: Integrating molecular gut content analysis with Structural Equation Modelling ## Authors: **Corresponding author**: Paul Henning Krogh, Aarhus University, [[e-mail]](mailto:[e-mail]), ORCID: [https://orcid.org/0000-0003-2033-553X](https://orcid.org/0000-0003-2033-553X) Ejgil VestergÃ¥rd Gravesen, [Molecular Ecology], [[e-mail]](mailto:[e-mail]) Lenka Dušátková, Masaryk University Kacie Athey, University of Illinois at Urbana-Champaign Jiayi Qin, Novo Nordisk (Denmark) ## Summary This dataset includes information on arthropod sampling and environmental variables collected at the Qassinnguit glacier foreland during the summers of 2015 and 2016. The data were used for Structural Equation Modeling (SEM) to analyze food web interactions and the impact of environmental factors. Combining DNA gut content analysis with SEM based on arthropod activity-density provides insights into bottom-...# 格陵兰退缩冰川前缘节肢动物食物网：整合分子肠道内容物分析与结构方程模型 将DNA肠道内容物分析与基于节肢动物活动密度的结构方程模型（Structural Equation Modelling，SEM）相结合，在格陵兰冰川前缘（glacier foreland）开展研究，使我们得以将元条形码测序（metabarcoding）技术获取的定性数据与基于定量数据的分析方法相结合。SEM分析揭示了受上行调控与下行调控共同驱动的食物链：上行调控对蜘蛛和盲蛛（harvestman）种群至关重要，而下行调控则是步甲（ground beetle）种群的关键调控机制。这些调控机制与捕食者的捕食策略密切相关：上行调控机制对应“坐等伏击型”捕食行为，而下行调控机制则与“主动搜寻型”捕食行为相关联。在植被演替的早期阶段，上行调控的种群动态发挥主导作用；而在远离冰川前端的植被演替后期阶段，下行调控占据优势。节肢动物捕食者与其潜在猎物间的调控级联效应存在从上行到下行的转变…… 研究于2015和2016年夏季开展，通过在冰川前缘不同生境斑块中布设的湿式陷阱诱捕器采集样本，同时采集土壤样品以开展环境特征表征。捕获的节肢动物被鉴定至物种或科级水平；对土壤样品进行了含水量与有机质含量分析；基于陷阱捕获量测算节肢动物的活动密度，并将环境变量与节肢动物种群数据进行关联分析；利用归一化植被指数（Normalized Difference Vegetation Index，NDVI）评估植被生物量。 ## 卡辛格伊特（Qassinnguit）采样时间与信息： 土壤样品采集：分别于2015年8月7日与2016年8月5日在卡辛格伊特冰川前缘采集土壤样品，以在晴朗干燥时段测定土壤含水量与有机质含量等环境变量。 NDVI扫描：归一化植被指数扫描工作于2016年8月1日完成。 节肢动物采样：节肢动物采样用的湿式陷阱诱捕器于2015年7月8日布设，持续采样至2015年8月7日，后续采样推迟至8月…… ## 作者列表 **通讯作者**：保罗·亨宁·克罗格（Paul Henning Krogh），奥胡斯大学，邮箱："[[e-mail]](mailto:[e-mail])"，ORCID："[https://orcid.org/0000-0003-2033-553X](https://orcid.org/0000-0003-2033-553X)" 埃吉尔·韦斯特高·格雷夫森（Ejgil Vestergaard Gravesen），《分子生态学（Molecular Ecology）》，邮箱："[[e-mail]](mailto:[e-mail])" 伦卡·杜沙托娃（Lenka Dušátková），马萨里克大学 凯西·阿西（Kacie Athey），伊利诺伊大学厄巴纳-香槟分校 秦佳怡（Jiayi Qin），诺和诺德（丹麦） ## 数据集概况 本数据集包含2015与2016年夏季在卡辛格伊特冰川前缘采集的节肢动物采样数据与环境变量数据，这些数据被用于结构方程模型（SEM）分析，以解析食物网相互作用与环境因子的影响。将DNA肠道内容物分析与基于节肢动物活动密度的SEM相结合，有助于深入解析上行……