Chi²:Chi-square test (P > 0.05 indicates absence of significant discrepancy between the data and the model); *: p<0.05; **: p<0.01; ***: p<0.001

Species richness showed significant positive direct effect on FEve (β = 0.53; P < 0.001; Table 3), which also showed positive and significant effect (β = 0.62; P < 0.001; Table 3; Figure 4a) on AGB. Therefore, species richness, through FEve had a positive significant effect on AGB (β = 0.53*0.62 = 0.39). Similarly, species richness, through structural diversity (CV DBH and CV Npb) showed positive significant effects on AGB (Table 3; Fig. 4b-c). However, when comparing the three SEMs, we found that the variation in AGB explained was greater for FEve (r²=0.39) than for CV DBH (r²=0.20) and CV Npb (r²=0.24). Further, when we combined functional evenness, CV DBH and CV Npb in the integrative SEM, only FEve showed significant mediation role in linking species richness to AGB (Table 3; Fig. 4d).

Table 3. Results of the SEMs testing the direct and indirect effects of species richness on AGB via functional evenness and structural diversity. Fit statistics are presented in Figure 3