Mycocoenology of roadside verges planted with beech trees (Fagus sylvatica L.) in Drente, The Netherlands
Keizer, P. J.
The macromycetes occurring in 23 plots in roadside verges planted with beech trees (Fagus sylvatica L.) were studied. The plots varied widely with regard to vegetation and exposition. The vegetation of vascular plants and of a number of environmental variables were studied as well. Samples of mycorrhizas were taken from a number of plots. Some different abundance values of the macromycetes were compared. On the basis of the green plants three vegetation types could be recognized. Using the ectomycorrhizal fungi the plots were divided in a species-poor and two species-rich types. The former did not correspond with a vegetation type but the latter two types corresponded to a limited extent with vegetation types. The two communities that were recognized among the saprotrophic fungi corresponded well with the vegetation types. The better correspondence of communities of vascular plants with those of saprotrophs than with those of ectomycorrhizal fungi indicates that plants and saprotrophs react more in the same way on the environmental variables than the ectomycorrhizal fungi. Environmental variables important for plants and saprotrophs are exposition of the plot, thickness of the organic layer, sodium concentration, Ellenberg N-indication values. Important for mycorrhizal fungi are: higher nitrate, potassium and magnesium concentrations for the species-poor type and exposition, thickness of the organic layer and age of the trees for the other types. The samples of plots of the type rich in ectomycorrhizal fungi had larger numbers of mycorrhizal root tips with a larger degree of ramification. There was a positive correlation between the number of mycorrhizal root tips and the species numbers. Logarithmized abundance values based on absolute maximum numbers of sporocarps, total numbers and dry weight production showed only minor differences.