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 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 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-...