1. Department of Applied Analytical and Physical Chemistry; Faculty of Bioscience Engineering; Isotope Bioscience Laboratory - ISOFYS; Ghent University; Coupure Links 653 9000 Gent Belgium
2. Department of Applied Ecology and Environmental Biology; Computational and Applied Vegetation Ecology - CAVElab; Ghent University; Coupure Links 653 9000 Gent Belgium
3. International Institute of Tropical Agriculture (IITA); c/o ICIPE P.O. Box 30772-00100 Nairobi Kenya
4. Centre de Recherche en Science Naturelles; Bukavu D R Congo
5. Department of Geography; Kenyatta University; P.O. Box 43844-00100 Nairobi Kenya