1. Department of Geosciences and Natural Resource Management (IGN); University of Copenhagen; Øster Voldgade 10 Copenhagen K 1350 Denmark
2. Leibniz Institute of Agricultural Development in Transition Economies (IAMO); Theodor-Lieser-Str. 2 06120 Halle (Saale) Germany
3. Institute of Steppe of the Ural Branch of the Russian Academy of Science (RAS); Pionerskaya str. 11 460000 Orenburg Russia
4. Laboratory of Geo-Information Science and Remote Sensing; Wageningen University; Droevendaalsesteeg 3 Wageningen 6708 PB The Netherlands
5. Department of Geography and Environmental Sustainability; University of Oklahoma; 100 East Boyd St. Norman OK USA