Exotic plants share putative fungal pathogens with natives
We found asymmetric sharing of pathogens between native and exotic plants along the exotic gradient (Fig. 3). The relationship between shared pathogens and exotic dominance in mixed communities (Fig. 3A) deviated significantly from null expectations (Fig. 3B). Exotic plants shared a greater proportion of pathogen OTUs than would be expected by chance, compared with native plants, which shared fewer pathogen OTUs than our null model predicted (Fig. 3) Plants shared 4% more pathogens in home compared with away soils (χ2=6.37, p=0.01, Table 1). The observed proportion of shared pathogens appeared to reach a peak when the community contained approximately 60% exotic plants, while it was lowest in communities with 25% exotic plants (when both native and exotic plants were present; Fig. 3). Further, the efficiency at which plants shared pathogens with other plants increased with the proportion of exotic plants in the community, as indicated by increasing values of closeness centrality with increasing exotic dominance (χ2=15.68, p<0.001, Table 1, Fig. 1D).