Arthropod food webs in the foreland of a retreating glacier: Gut content analysis and structural equation modeling (SEM)

Below- and above-ground arthropod communities were explored at a glacier foreland area in low Arctic Southwest Greenland aiming for a better understanding of the mechanisms behind the arthropod succession driven by increasing temperatures in the context of an Arctic climate change scenario. Arthropods were sampled in 2015 and 2016 along a downslope transect where the microclimate became warmer downhill a chronosequence towards a climax vegetation. The arthropod data sets were analyzed in relation to an environmental data set. 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. The shift from bottom-up to top-down cascades between arthropod predators and their potential prey populations was mainly driven by increasing temperatures away from the glacier. Structural equation modeling (SEM) shows bottom-up and top-down controlled food chains as bottom-up contro..., 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., , # Arthropod food webs in the foreland of a retreating glacier: Gut content analysis and structural equation modeling (SEM)

## Description of the data:

Information about location and patch habitats on a transect sampled during the summer of 2015 and the summer of 2016.

* Year and transect position
* Habitat
* Patch label

Information about environmental variables sampled at each patch on the transect.

* Meters above sea level (MASL)
* Distance to snow, m
* NDVI (Normalized Difference Vegetation Index) - label where * indicates estimated NDVI value
* Mean lichen diameter, mm
* Time since deglaciation, years
* Soil water percent in the topsoil
* Organic matter percent in percent in the topsoil

Information about arthropod activity densities (catch numbers per pitfall trap) during the summer of 2015 and the summer of 2016.

* Arthropod predators
* Parasitoid
* Mites
* Collembola
* Diptera