High alpine communities are expected to be strongly impacted by climate change, with many of the effects being indirect and modulated by local factors. For the past 6 years we have sampled the zooplankton communities and abiotic parameters of 18 high-alpine lakes in the Hohe Tauern national park in central Austria. The lakes encompass a wide range of size, altitude, maximum depth, age and accessibility. Microclimate is a dominant driver of the annual temperature cycle, with long-term trends only now emerging. Zooplankton communities show high beta diversity, with many species only occurring in a single lake. Both morphological and molecular data show that lakes in close geographic proximity are very different from another, with only water bodies with direct physical connections to one another being similar in their diversity. However, over the period of the study, dissimilarity appears to be declining, at least in terms of zooplankton morphological diversity.  There is also evidence that colonization by new species has the potential to have community-level effects.  Several of the lakes have deep chlorophyll maxima with at times remarkably high chlorophyll values, albeit with high interannual variability. However, with logistical restraints limiting sampling to one date per year, the degree of intra-annual variability in the chlorophyll and zooplankton data remains unexplored. These data provide a baseline to measure the impending changes in high alpine aquatic communities brought on by climate change.

Primary Presenter: Stephen Wickham, University of Salzburg (stephen.wickham@plus.ac.at)

Authors:

Ulrike-G. Berninger, University of Salzburg / Dept. of Environment and Biodiversity  (ulrike.berninger@plus.ac.at)

Jana Petermann, University of Salzburg / Dept. of Environment and Biodiversity  (jana.petermann@plus.ac.at)