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

The Arctic has warmed nearly four times faster than the global average since 1979, resulting in rapid glacier retreat and exposing new glacier forelands. These forelands offer unique experimental settings to explore how global warming impacts ecosystems, particularly for highly climate-sensitive arthropods. Understanding these impacts can help anticipate future biodiversity and ecosystem changes under ongoing warming scenarios. In this study, we integrate data on arthropod diversity from DNA gut content analysis—offering insight into predator diets—with quantitative measures of arthropod activity density at a Greenland glacier foreland using Structural Equation Modelling (SEM). Our SEM analysis reveals both bottom-up and top-down controlled food chains. Bottom-up control, linked to sit-and-wait predator behavior, was prominent for spider and harvestman populations, while top-down control, associated with active search behavior, was key for ground beetle populations. Bottom-up controlled..., Data CollectionData were collected using wet pitfall traps established across various patches within the Qassi glacier foreland and supplemented with data retrieved from the GEM (Global Ecological Monitoring) database for Kobbefjord. The specific timelines for data collection are as follows:

Qassi 2015 Sampling:

Wet pitfall traps were set up on July 8, 2015, and continuous sampling occurred until August 7, 2015. Sampling was interrupted due to rainy weather and resumed from August 12 to August 20, 2015.

Qassinnguit 2016 Sampling:

Wet pitfall traps were established on July 6, 2016, with continuous sampling until August 5, 2016. After a pause due to rain, sampling continued from August 10 to August 19, 2016.

Soil samples were collected at Qassi on August 7, 2015, and at Qassinnguit on August 5, 2016, to characterize environmental variables, specifically measuring soil water content and organic matter during dry weather conditions. NDVI (Normalized Difference Vegetation Index) me..., , # 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 Vestergård 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 Qassi glacier foreland and Kobbefjord 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 in...