Regional Mountain Conference

As part of the long-term monitoring of ecosystem processes in Hohe Tauern National Park (Austria) the third sampling of the “Soil Mesofauna” module was conducted in 2024, following initial samplings in 2017 and 2022. The subproject is conducted on permanent transects spanning a few meters to capture fine-scale environmental gradients and their effects on soil mesofauna. Along gradients from typical snowbed communities to fully developed alpine grasslands, distinct organisms are expected to occur.

The study sites include Oberettes (Italy), Furka (Switzerland), and three sites within Hohe Tauern National Park (Innergschlöss, Seebachtal, Untersulzbachtal). Snowbed plots hosting specifically adapted plant communities were selected. Transects were defined based on biomass productivity and divided into three sectors: head (highest productivity, first snow-free), middle, and bottom (lowest productivity, longest snow cover). Species- and individual-rich mesofauna groups like springtails (Collembola) and mites (Oribatida) were sampled and identified, as they were considered suitable indicators of ecological changes in these microhabitats. The study combined quantitative (population density) and qualitative (species-level identification) approaches.

Results from the three sampling years showed no clear trend of mean Oribatida and Collembola densities along transects. Nonetheless, Oribatida densities were more closely linked to the studied gradient. Comparisons of species composition revealed strong similarities in abundant Oribatida species across years at individual sites, whereas Collembola showed greater interannual variation. Significant changes occurred among low-density species: 18 “new” adult Oribatida species were recorded in 2024, while 18 species from previous years were absent. In 2024, 51 Oribatida species (26–29 per site) and 32 adult Collembola species (21–24 per site) were recorded, indicating higher Oribatida richness and greater Collembola overlap among sites. In 2024, dominant Collembola species across sectors tended to be generalists, whereas Oribatida communities were more diverse and balanced, with a mix of generalists and specialists showing more sector-specific abundance patterns.

In conclusion, Collembola might be less suitable indicators of differences along the investigated fine-scale gradient, although monitoring hygrophilous species could be informative of environmental changes. Oribatida appeared more promising for tracking changes.