Fig. 2: Density plot comparing the observed and expected distribution of the minimum phylogenetic distances between preferred and non-preferred host species.

Fungal DNA was extracted of the roots of each plant, grouped into operational taxonomic units (OTU), and used to assess plant-fungal interaction networks. For each fungal operational taxonomic unit (OTU), the information across the 15 fragments was used to define its preferred (or non-preferred) hosts. Preferred hosts were considered those plant species that actually harbored the fungal OTU in more than half of the times that both partners occur in the same fragment (i.e., number of opportunities to interact). For each OTU in each fragment (n = 388), it was calculated the average phylogenetic distance from its non-preferred hosts (but actually harboring the OTU) to their nearest relative among the preferred hosts (black line). Simultaneously, for each OTU in each fragment, the same number of hosts was randomly selected from the set of plant species present in the fragment, excluding the preferred plant species (gray line).