1 Department of Plant Ecology and Nature Conservation, University of Potsdam, Am Mühlenberg 3, 14476, Potsdam, Germany.
2 Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195, Berlin, Germany.
3 Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia.
4 Global Change Biology Group, Botany and Zoology, University of Stellenbosch, Merriman Avenue, Stellenbosch, 7600, South Africa.