1. Institute of Ecology Leuphana University of Lüneburg Lüneburg 21335 Germany
2. Copernicus Institute of Sustainable Development Utrecht University Utrecht 3584 CB the Netherlands
3. Division of Biological Sciences and Institute on Ecosystems University of Montana Missoula MT 59812 USA
4. Institute of Ecology and Earth Sciences University of Tartu Liivi 2 50409 Tartu Estonia