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Reservoir shorelines of regulated rivers, created by over 2.8 million dams worldwide, have experienced substantial biodiversity loss, particularly in plant communities. While actively introducing local riparian plants is a common restoration strategy, existing approaches often lack applicability and transferability across river basins. To address this, we propose a guild-based restoration framework that classifies plant species used for restoration into guilds based on shared functional traits and adaptive strategies. This approach allows for evaluating restoration outcomes across guilds along environmental gradients, optimizing restoration design.

We tested this framework along the shorelines of the Three Gorges Reservoir (TGR), characterized by steep environmental gradients. Plant guilds were identified based on shared functional traits, focusing on hydrological and geomorphological associations. The effectiveness of guild introductions was assessed across gradients of submergence intensity, topography and substrate properties by comparing outcomes to those of spontaneous colonization.

Results showed that under intermediate and high submergence intensity, active plant introduction and spontaneous colonization yielded similar restoration outcomes, with short-clonal flood-tolerant herbs naturally dominating. At low submergence intensity, the introduction of flood-tolerant woody plants increased functional diversity, whereas tall-clonal flood-tolerant herbs reduced diversity due to competitive exclusion. Actively introduced plants did not suppress invasive species. Unexpectedly, under intermediate submergence intensity, the introduction was associated with increased invasive plant presence.

Synthesis and applications: Our study validates the guild-based framework as an effective approach for shoreline vegetation restoration in regulated rivers. We show that guild identity and submergence intensity jointly shape restoration outcomes, offering insights for optimizing active plant introduction strategies in the TGR and similar reservoirs in the upper Yangtze River. Furthermore, this framework enhances the transferability of restoration practices by offering a functionally driven approach to species selection across river basins.