*3.2. Comparison between OG and NOG Forest Stands*

With the exception of the species occurring in only one plot, OG and NOG stands shared most of the common species detected in the study area (83% of the vegetative species and 83% of the sexual ones) and also a significant part of the rare species (58% and 71%, respectively). Further, rare species (both vegetative and sexual) were more exclusive than common ones, above all in NOG stands where they represented more than 20% of the species (Figure 3).

In terms of both alpha and gamma diversity, OG and NOG forest sites did not show statistically significant differences for any combination of groups of species considered (rare vs. common, vegetative vs. sexual) (Table 2, Wilcoxon test, *p* > 0.05).

**Figure 3.** Schematic representation of shared and exclusive species in the OG and NOG forests of the study area (dataset without the species occurring only in a single plot, 34 species). The definition of "common" or "rare" species follows their commonness–rarity values in montane and humid sub-Mediterranean Italy (Nimis 2016).


**Table 2.** Descriptive statistics of lichen species richness: alpha diversity (average number of species on each tree within a plot) and gamma diversity (average overall number of species within a plot). Results of the Wilcoxon test performed for the two groups of plots are also reported. n.s.: not significant (*p* > 0.05).
