<b>Environmental Filtering Drives Plant Community Assembly in Riparian Wetlands of the Three Gorges Reservoir Region: Functional–Phylogenetic Decoupling and Environmental Driving Mechanisms</b>

Focusing on riparian wetland plant communities in the Three Gorges Reservoir Region, we classified communities using the competitive–stress‑tolerant–ruderal ecological strategy framework and characterised their assembly using the standardised effect size (SES) of functional diversity (SES_RaoQ), the standardised effect sizes of phylogenetic diversity (SES_MPD and SES_MNTD), and functional diversity–phylogenetic diversity (FD–PD) coupling analysis.

We then examined environmental drivers of assembly using extreme gradient boosting and shapley additive explanations models. Across plant community types, SES_RaoQ values were significantly lower than random expectations, whereas SES_MPD and SES_MNTD generally did not differ significantly from random expectations, indicating pronounced functional clustering alongside predominantly random phylogenetic structure. FD–PD coupling analysis showed that all community types were predominantly characterised by the FD < PD decoupling pattern, indicating that species from diverse phylogenetic lineages possess similar functional traits that facilitate adaptation to the riparian wetland environment.