Affiliation: | Experimental and Systems Ecology, University of Bielefeld, Universitätsstrasse 25, D–33615 Bielefeld, Germany;;Present address: UniversitéHenri PoincaréNancy I, Facultédes Sciences, UMR UHP/INRA 1137 'Ecologie et Ecophysiologie Forestières'–BP 239, F–54506 Vandoeuvre-lès-Nancy cedex, France |