(iii) Plant community-, environment- and soil-mediated relationships between elevation and above- and belowground plant pathogens
The final SEM (Fisher’s C = 11.855, P = 0.158, d.f. = 8) revealed that increasing Elevation was associated with a significant decrease in Soil PCA1 (standardized path coefficient β = -0.768, P = 0.038) (Fig. 2b; Table S1.7). WhileElevation showed strong negative direct correlation withsfpOTUs (β = -1.109, P = 0.015) but not PL (β = -0.159, P = 0.563). Furthermore, Evenness (β = -0.296,P = 0.082) and Proneness (β = 0.665, P < 0.001), rather than Soil PCA1 (β = -0.180, P = 0.482), were associated with variation in PL . In contrast, significant reduction in sfpOTUs was associated with increasing Soil PCA1 (β = -0.540, P = 0.026), but not Evenness (β = 0.063, P = 0.672) or Proneness (β = 0.097, P = 0.529) (Fig. 2b; Table S1.7). The final SEM accounted for 45.772% of variation in PL and 55.855% of variation in sfpOTUs . In addition, the residual plots also showed that changes in bothProneness and Evenness were associated with variation inPL , while increasing Soil PCA1 was associated with a significant decrease in sfpOTUs (Fig. S1.10). This indicates the important role of plant community in explaining variation in PL , and highlights the indirect connection between elevation and belowground plant pathogens via abiotic factors.