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Reference sites

Reference sites are additional sites in states of initial development but under different environmental conditions. By means of such reference sites characteristic processes and structures of the initial development state found in the artificial catchment area will be compared and validated. Site specific processes and structures can be distinguished from those which are specific for the initial states of ecosystems in general. In addition well documented reference sites can also be used for the validation of hydrological models optimized at the artificial catchment area under divergent conditions. In terms of chronosequences, reference sites can illustrate and help to understand the temporal process of developing ecosystems. Examples for reference sites of the SFB/TRR are inland dunes, glacial fronts as well as post-mining landscapes.

A large number of inland dunes can be located within the state of Brandenburg (Germany) partially originating from the end of Pleistocene. Numerous dunes have been build up during medieval settlement phases with increased erosion and accumulation processes. Covered by forest stands corresponding fossil soil horizons have been preserved frequently under sandy accumulations and dunes. Furthermore, recent sand dislocation processes are frequent on former military sites. Large areas without vegetation cover exist near Cottbus and Jüterbog (Southern Brandenburg). Inland dunes are still active on these sites. They are adequate reference sites as different stages of ecosystem genesis starting with a well defined zero point can be studied. Dune sites in Brandenburg are documented by the Brandenburg Geological Survey (LBGR) so that information about the age and former land use are available. Further, comprehensive investigations of inland dunes have been carried out in the forefront of open-cast mines in Lusatia (Germany), while numerous age determinations of Neolithic and medieval sand accumulation phases have also been carried out by means of archaeological findings.

The ETH Zurich investigates the initial development of ecosystems in the Swiss Alps in the front end of the Damma glacier (Kanton Uri, municipality of Göschenen). Instrumented investigation sites exist for monitoring and process studies. The Damma glacier has been retreating for several decades so that the development of soil structures and vegetation can be investigated continuously at uncovered areas. The continuous retreat offers the chance for chronosequence studies. The oldest reference site at the front end of the Damma glacier has an age of 70 years. Accordingly, comprehensive results are existent especially in the field of soil biology. The colonization of the developing soils by micro-organism has been investigated looking primarily for limiting factors in the initial state. Further, interactions between the established pioneer vegetation and the invading micro-organism have been studied. These well documented investigation sites will be included here in order to validate the occurrence and impact of processes in the initial ecosystem genesis under significantly different climatic conditions. In addition, streams in glacial fronts can be used as reference sites for the limnological studies of the SFB/TRR.

In later project phases additional reference sites will be added. E.g. the research project is in contact with institutions from Hawaii where volcanic sites of different ages may be included.