1Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
2Institute for Landscape Biogeochemistry, Leibniz Center for Agricultural Landscape Research e.V. (ZALF), Leipniz, Germany
3Institute of Biology, Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Germany
4German Centre for Integrative Biodiversity Research (iDiv) Leipzig, Germany
5Forest Research Institute Baden-Württemberg, Freiburg, Germany
6Research Unit Forest dynamics, Swiss Federal Research Institute for Forest, Snow and Landscape Research WSL, Zürchestr. 111, 8903 Birmensdorf, Switzerland
7Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195 Berlin, Germany
Received: 16 Jun 2014 – Discussion started: 07 Oct 2014
Abstract. Precipitation patterns across Central Europe are expected to change over the 21st century due to climate change. This may reduce water availability during the plant-growing season and hence affect the performance and vitality of forest ecosystems. We established a novel rainfall reduction experiment on nine sites in Germany to investigate drought effects on soil–forest–understory ecosystems. A realistic, but extreme annual drought with a return period of 40 years, which corresponds to the 2.5% percentile of the annual precipitation, was imposed. At all sites, we were able to reach the target values of rainfall reduction, while other important ecosystem variables like air temperature, humidity, and soil temperature remained unaffected due to the novel design of a flexible roof. The first year of drought showed considerable changes in the soil moisture dynamics relative to the control sites, which affected leaf stomatal conductance of understory species as well as evapotranspiration rates of the forest understory.
Revised: 19 Jan 2015 – Accepted: 20 Jan 2015 – Published: 17 Feb 2015
Gimbel, K. F., Felsmann, K., Baudis, M., Puhlmann, H., Gessler, A., Bruelheide, H., Kayler, Z., Ellerbrock, R. H., Ulrich, A., Welk, E., and Weiler, M.: Drought in forest understory ecosystems – a novel rainfall reduction experiment, Biogeosciences, 12, 961-975, doi:10.5194/bg-12-961-2015, 2015.