FIGURE 3 . The results of structural equation modelling (SEM) showing the relationship between precipitation, nitrogen addition (N), phosphorous addition (P), arbuscular mycorrhizal fungi (AMF), and dominant species shoot biomass with above-ground net primary productivity (ANPP) across two years. Numbers adjacent to arrows are standardized path coefficients and suggest the effect size of the relationship. The proportion of variance explained (R 2) appears alongside the response variables in the model. Arrows indicate significant (black and solid) and non-significant (gray and dashed) relationships. Goodness-of-fit statistics for each model are shown below the model. χ2 = 15.167, p = 0.232, d.f. = 12; RMSEA = 0.058, p = 0.302; AIC = 81.167.