Figure 5

Structural equation model showing the direct and indirect effects of spatial factors, climate, soil pH, nutrients and plant species richness on soil microbial richness (a), and their standardized total effects (direct plus indirect effects) derived from the structural equation model of microbial richness (b). Numbers adjacent to arrows are path coefficients, and width of the arrows is proportional to the strength of path coefficients. Continuous and dashed arrows indicate positive and negative relationships, respectively. Significance level: *P < 0.05; **P < 0.01; ***P < 0.001.