Elevational patterns and environmental explanations
According to the results of polynomial regression, phylogenetic and morphological structure as well as species richness (SR) in LSD all exhibited significant (p< 0.05) linear or binomial pattern along elevational gradient (Fig. 3 and S1; Table S5). In RED, phylogenetic structure (SES.MPD) and morphological structure for size-related morphological attributes (SES.PWsize) exhibited non-linear relationship with elevation, shape-related morphological structure and SR exhibited significant linear and quadric relationship with elevation (Fig. 3 and S1; Table S5).
    According to the results of forward selection, we found that the best predictors varied across datasets and facets of community structure (Table S6). In SEMs, there were positive correlations between phylogenetic and morphological structures in LSD (Fig. 4, a), which were extremely weak in RED (Fig. 4, b).