EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Individual versus combined effects of elevated CO2, warming and drought on grassland productivity and stoichiometry

Michael Bahn1, David Reinthaler1, Hans-Peter Piepho2, Erich Pötsch3, Andreas Schaumberger3, Markus Herndl3, Kathiravan Meeran1, Rüdiger Kaufmann1, Jesse Radolinski1, Maud Tissink1, and the ClimGrass-Team*
Michael Bahn et al.
  • 1University of Innsbruck, Department of Ecology, Innsbruck, Austria (
  • 2University of Hohenheim, Hohenheim, Germany
  • 3HBLFA Raumberg-Gumpenstein, Irdning, Austria
  • *A full list of authors appears at the end of the abstract

In a future world, ecosystems will be affected by a concomitant increase in atmospheric CO2 concentrations, temperature and drought events. While the individual effects of elevated CO2, warming and drought on plant and ecosystem productivity are comparatively well understood, there is a major lack of experimental studies testing for their interactive effects. In a multifactor experiment (ClimGrass) established in 2013 on a managed montane grassland in Central Austria we tested how elevated CO2 (eCO2), warming (eT) and drought individually and interactively affect productivity and tissue stoichiometry.

Treatment effects varied and amplified across the eight treatment years, partly related to shifts in species composition. Above-ground net primary productivity (ANPP) was generally increased when eT and eCO2 were combined, while it was not consistently affected by the individual treatments. Drought and drought recovery effects on ANPP, gross primary productivity (GPP) and belowground carbon allocation were amplified when drought was combined with eT and eCO2. Both under current and future (eT, eCO2) scenarios drought altered tissue stoichiometry by decreasing phosphorus concentrations during drought and increasing nitrogen and potassium concentrations post-drought. Overall, our study suggests that in the temperate grassland studied drought had an overriding effect on productivity and tissue stoichiometry, which was amplified by warming, but only weakly altered by elevated CO2


Silvia Caldararu, Alberto Canarini, Lisa Capponi, Johannes Ingrisch, Lumnesh Joseph, Ansgar Kahmen, Matthias Kandolf, Andreas Klingler, Andreas Richter, Medardus Schweiger, Matevz Vremec, Wolfgang Wanek

How to cite: Bahn, M., Reinthaler, D., Piepho, H.-P., Pötsch, E., Schaumberger, A., Herndl, M., Meeran, K., Kaufmann, R., Radolinski, J., and Tissink, M. and the ClimGrass-Team: Individual versus combined effects of elevated CO2, warming and drought on grassland productivity and stoichiometry, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15918,, 2023.