1. MTA Centre for Ecological Research, Evolutionary Systems Research Group, Klebelsberg Kunó u. 3, H-8237 Tihany, Hungary and
2. MTA-ELTE Research Group in Theoretical Biology and Evolutionary Ecology and Department of Plant Systematics, Ecology and Theoretical Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány1/c, H-1117 Budapest, Hungary. Phone: , Fax: .