fungal pathogens; host specificity; forest trees; vegetation categories; wood-decay

Ganoderma P. Karst. is a genus of wood decaying fungi with complicated taxonomy due to morphological variability of their basidiomata. Although a wide range of host plants is assumed for the genus as a whole, there is a need for revision of the host specificity of individual species. Based on revision of mycological collections across the Czech Republic we analyzed the ecological trends of six European species, including host preferences and propensity to parasitism. Individual Ganoderma species were sampled differentially along vegetation categories, with G. adspersum (Schulzer) Donk prevailing in habitats with high anthropogenic factors and G. applanatum (Pers.) Pat. in natural vegetation with limited anthropogenic influence, differing also in average altitude of sampling. The number of host species of individual Ganoderma spp. did not reach an asymptote, suggesting an open host plasticity and great potential for finding new host associations in future. Very distinct host compositions were found for individual Ganoderma species, at the genus level, with G. applanatum being the least host specific. Individual Ganoderma species differ also in their tendency to parasitic life strategy. The proportion of parasites increases with decreasing vegetation category and it is therefore higher in urban than natural environment, especially on hardwood trees.