SP 5: Decomposition and nutrient cycling

The functional significance of forest diversity: N-pools, fluxes and N-uptake complementarity

Principal investigator(s):

Prof. Dr. Michael Scherer-Lorenzen (University of Freiburg)  

Co-Principal investigator(s):

Prof. Dr. Andy Hector (University of Zurich)  
PD Dr. Pascal Niklaus (University of Zurich)  

Phd candidate(s):

Katrin Seidelmann (University of Freiburg)  

Contact adress:

Faculty of Biology, Geobotany, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany

Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland


Subproject 5 focuses on leaf litter decomposition as a key process in nutrient cycling. Several lines of experimentation will yield insights on controlling factors of litter decomposition, including abiotic and biotic components of the ecosystem.

The general objectives of subproject 5 are:

  • To study the effect of environmental conditions on leaf litter decomposition processes, and how this will change with tree diversity ("ecoscape” approach").
  • To test effects of tree diversity on leaf litter decomposition processes and nutrient uptake (NILEx).

Litter bags of the decomposition experiment (K. Seidelmann)

For the “ecoscape” approach, a total of 4131 litter bags were filled with single-species litter of Osmanthus fragrans, Pinus massoniana and Schima superba, respectively. These bags have been fixed on the soil surface across both field sites. The positioning of the litter bags differ in topographic features, and in the diversity of the newly planted tree species. By studying the litter decomposition dynamics over time, we will thus quantify the effects of topography and micro-relief on decomposition dynamics.

Subproject 5 is coordinating the New Integrated Litter decomposition Experiment (NILEx) that combines the quantification of diversity effects on decomposition processes, nutrient uptake, microbial use, and soil erosion. In this experiment, the diversity of tree litter species has been manipulated, using both unlabelled, and 15N- and Li-labelled litter. We will measure litter decomposition rates and nutrient dynamics of the decomposing litter, and follow the transfer of nutrients from the litter to growing plants.

Experimental setting in Site B (K. Seidelmann)