Regional Mountain Conference

Artificial snow production is becoming increasingly essential for ski operations under climate change, leading to the construction of mountain reservoirs across the Alps. While these reservoirs can alter mountain ecosystems and landscape structure, they also provide novel habitats for aquatic organisms such as zooplankton. In addition to the inherent harshness of alpine environments, organisms in these systems must withstand fluctuations in water levels and frequent artificial mixing. Here, we surveyed zooplankton and recorded physicochemical variables in eleven mountain reservoirs in the Eastern Alps to document species occurrence, assess similarity to nearby natural alpine lakes, and identify environmental correlations. Zooplankton were present in all mountain reservoirs (22 taxa in total; 1-11 taxa per reservoir; mean 7 taxa). The species composition broadly resembled that of adjacent natural lakes, and nearby reservoirs tended to be compositionally similar. Zooplankton abundances varied widely  (summer: 0.09-168.74 Ind L⁻¹; autumn: 0.04-1092.78 Ind L⁻¹) and were significantly related to environmental variables including elevation, dissolved organic carbon, food availability (chlorophyll a), pH, K⁺, total phosphorus, and Ca²⁺. Rotifers dominated numerically, whereas crustaceans dominated biomass. Overall, local environmental conditions had a stronger effect than regional factors on these rapidly changing systems. Despite their artificial origin, mountain reservoirs support zooplankton communities that are comparable to those in natural lakes, thus improving our understanding of the distribution of zooplankton in remote mountain regions.