A 15N tracer study to disentangle trophic relations of decomposer species in high alpine soils

Julia Seeber (PI), Michael Steinwandter, Alexander Rief


With the help of a 15N tracer study we will check whether the trophic affiliation of specific decomposer species as indicated by their natural 15N values is correct. The analysis of the data obtained in the 15N tracer study will include a temporal aspect: we expect the 15N signal to first appear in the primary decomposers at the first sampling dates and to further increase in specimens collected on the later sampling dates. Consequently, secondary decomposers, sustained on organic material already processed by the primary decomposers, are expected to show no or only minimal enrichment in 15N at the first two sampling dates and their 15N signatures should increase later. By conducting the experiment on patches dominated either by earthworms or by arthropods we will be able to evaluate the performance of these two important decomposer groups on litter decomposition. In patches where earthworms occur the 15N signal will appear faster in the foodweb than in patches where arthropods predominate.


Funding: Berglandwirtschaft (University of Innsbruck)

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Tracer experiment