1 Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany. Electronic address: kstein@zalf.de.
2 Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany.
3 Eberswalde University for Sustainable Development, Eberswalde, Germany.
4 Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany; Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.