Abstract ID: 3.11306 | Accepted as Talk | Talk | TBA | TBA

Glacier shrinkage caused by climate change is altering hydrological dynamics of alpine headwaters, such as glacier streams and spring brooks (non-glacial springs). This in turn may affect aquatic biodiversity. Streams originating from rock glaciers (permafrost-related rocky landforms) maintain cold water temperatures even as climates warm. For this reason, these “icy seeps” may serve as crucial refugia for cold-adapted organisms. However, our knowledge on stream benthic macroinvertebrates dwelling in icy seeps is still scarce. In this study we investigated the physical (discharge, temperature and turbidity) and chemical (such as major ions and trace elements) conditions, meltwater contribution (estimated with δ18O and δ2H), and the invertebrate communities of glacier streams, spring brooks and icy seeps in five different catchments of the Eastern Italian Alps. When compared with the communities of the other two habitat types, icy seeps had intermediate diversity and composition, that were related to a gradient of chemical and physical harshness. While icy seeps with low concentrations of trace elements hosted communities like those dwelling in spring brooks, icy seeps with the harshest water chemistry (high Ni, As, U, Mn, Al concentrations) and higher meltwater contribution hosted species that are currently in decline due to glacier loss (e.g., Diamesa steinboecki). Our study represents a first attempt of drawing parallels and comparisons between the different alpine spring habitats, and includes a detailed characterization of Chironomidae, the most diverse and abundant group in high alpine headwaters. Our findings highlight the high conservation value of icy seeps and their ecological significance. The protection of these habitats, nowadays overlooked, will be fundamental under the progressive warming and dry-out risk of alpine springs.