Concordance between vascular plant and macrofungal community composition in broadleaf deciduous forests in central Italy

We examined the concordance between vascular plants and macrofungi (grouped into trophic groups) in Mediterranean forest habitats (central Italy). Our goal was to test how consistently plant and fungi groups classify plots in a broadleaf deciduous forest dominated by Quercus cerris. Our hypothesis was that groups of plants can be used as surrogates for the classification of macrofungal communities. The test of concordance comprised two steps: (1) the plant species data sets were subjected to cluster analysis, to obtain three classifications based on presence of all plants, presence and frequency of only woody species; (2) Multiple Response Permutation Procedures (MRPP) was used to test the performance of each plant classification applied to the fungi data sets. Sample scores on the first PCA axis were used to investigate the relationships between compositional patterns. In the concordance analysis, the classification based on woody plants only provided better results than the classification obtained using both herbaceous and woody plants. Cross-tests gave the best results when the "woody plants" classification was applied to ectomycorrhizal fungi (EMF) and, to a certain extent, to humicolous saprotrophs (Sh). The ordination analysis suggested that the frequency of woody plants follows a similar spatial distribution to EMF and Sh fungal groups and is therefore expected to covariate along the same environmental gradients. Many EMF exhibit preferences for few (one or two) hosts. Significant associations were found among numerous EMF and woody plant species. Woody plants such as Sorbus domestica and Prunus spinosa appear to be associated with many EMF. The combination of a high frequency of Fraxinus oxycarpa and Quercus petraea seems to promote distinct assemblages of EMF and Sh fungi. Characteristic assemblages of fungi were found in association with certain tree and shrub combinations.