Fig. 4: Principal coordinate analyses of Bray–Curtis distances of Hellinger transformed relative abundance data showing dissimilarities among communities for mutualists (AMF), pathogens, and saprotrophs occurring in North America (pink, n = 16), Europe (blue, n = 3), Africa (maroon, n = 3), and Australia (peach, n = 3) in either control plots (circles) or plots that had received nitrogen (squares), phosphorus (triangles), or both (diamonds).

Error bars around the means represent standard error. Communities of all guilds differed among continents using PERMANOVA (p < 0.001), but nutrient treatments had no consistent effect on composition, most likely due to high community turnover among sites and low sequence numbers resulting in low power. Results were not different when dissimilarities were assessed based on Raup-Crick transformed presence/absence data.