Monitoring potential impacts of climate change on the biodiversity of springs and springbrooks in the Central Alps

Headwaters in alpine regions and their biodiversity are particularly threatened by climatic changes. Most predictions on their response to climate change are based on modeling approaches. Empirically gained data rarely exist for glacially influenced and groundwater-fed headwaters. In 2019, long-term monitoring was initiated at 15 springs, 8 springbrooks and 2 brooks in the UNESCO Biosphere Reserve Engiadina Val Müstair. The goal was to gain data on hydro-ecological aspects over several decades to understand whether (1) the environmental conditions change over time and (2) how these changes influence the composition of the species assemblages. Water temperature loggers were installed, pH, electrical conductivity, oxygen, nutrients and discharge were measured three times per year, and ecomorphological features were mapped two times per year. The meio- and macrofauna was sampled in 2019, 2020 and 2021 with a semi-quantitative approach. The results of the first 5 years of monitoring show that the physico-chemistry, water temperature and discharge confirm the stable character typical for groundwater-fed systems. Certain seasonal variability is evident, which possibly indicates an influence of permafrost or snow meltwater. The composition of the species assemblages differs significantly between sites but stays relatively constant over time within a site. Elevation and the availability of wood—parameters indicating forestation—significantly influence the species composition. This study provides a solid baseline on the environmental conditions and the fauna in springs and springbrooks in the Central Alps, which is needed for a proper interpretation of changes identified on a long-term basis.