Raf Aerts1, Gezahegn Berecha2, Olivier Honnay3. 1. Plant Conservation and Population Biology, University of Leuven, Kasteelpark Arenberg 31-2435, BE-3001 Leuven, Belgium. raf.aerts@bio.kuleuven.be. 2. Plant Conservation and Population Biology, University of Leuven, Kasteelpark Arenberg 31-2435, BE-3001 Leuven, Belgium. Department of Horticulture and Plant Science, Jimma University, Jimma, Ethiopia. 3. Plant Conservation and Population Biology, University of Leuven, Kasteelpark Arenberg 31-2435, BE-3001 Leuven, Belgium.