Deciduous trees as lichen phorophytes: biodiversity and colonization patterns under common garden conditions

Common gardens are experimental plantations for comparing the performance of tree species while eliminating many of the variables that prevail in natural tree stands. The aim of this study was to evaluate the biodiversity of corticolous lichens on Danish tree species ( Acer pseudoplatanus , Alnus glutinosa , Betula pendula , Fagus sylvatica , Fraxinus excelsior , Quercus robur and Tilia cordata ) under common garden conditions and to examine the height distribution of particular lichen species. Observations were recorded through regular sampling of at least 36 lichen species on the main stems (from the base of the stem to the treetops) of 44-year-old trees at four common garden sites. Acer pseudoplatanus and Fraxinus excelsior had the greatest lichen species richness and Shannon diversity values while these measures were significantly lower for Betula pendula and Fagus sylvatica . The distribution of lichen species appeared biased among tree species. The general lichen distribution and relative sample height were weakly related (nonmetric multidimensional scaling). However, single lichen species showed a clear differential distribution along the tree stem ( P