Acknowledgments
We are grateful to Katja Steininger, Ute Petersen, Elke Tietz, H.
Fleischmann, and the land owners for their assistance in carrying out
the fieldwork. We also thank Stefan Mecke and Antonia Ortmann for their
assistance with GIS analysis. The authors are grateful to P. Michels for
proving valuable comments and suggestions on the manuscript language.
This study was funded by a research Grant (Grant No. 91563454) from the
German Academic Exchange Service (Deutscher Akademischer
Austauschdienst , DAAD) to the corresponding author.