Applied paleoecology for macrophyte restoration: Defining Anthropocene baselines in Lake Liangzi

Abstract The global degradation of freshwater lakes threatens biodiversity and critical ecosystem services. Restoring aquatic macrophytes is essential for reversing this decline, yet a fundamental challenge persists: the debate between aiming for historical baseline conditions or accepting novel ecosystems in the Anthropocene. This dilemma is exacerbated by a lack of long‐term data about pre‐degradation states. Current assessments are based mainly on short‐term in situ observations, providing limited insights into historical reference conditions and hindering the development of effective restoration targets. Here, we develop an evolutionary restoration methodological approach that integrates sedimentary ancient DNA ( seda DNA), pollen, macrofossils, satellite remote sensing and contemporary surveys to determine the centennial‐scale trajectory of macrophyte communities and inform their restoration targets. Taking Lake Liangzi (eastern China) as a case study, our results show that submerged taxa (e.g. Potamogeton crispus , Najas minor and Chara spp.) dominated under oligotrophic conditions until the 1960, after which nutrient pollution drove a shift to floating‐leaved and emergent taxa (e.g. Nelumbo nucifera , Nymphaea macrosperma and Pontederia crassipes ), and eventually to an algal‐dominated regime. Ecological Quality Ratio (EQR) assessments reveal a clear degradation trajectory in Lake Liangzi; macrophytes' ecological quality declined from Good (pre‐2010) to Poor (present). The results indicate that restoration to pre‐1960 baseline conditions is unlikely to be directly achievable. Instead, we propose a phased restoration pathway that first targets re‐establishment of the ecologically functional Anthropocene baseline represented by the 1960–2010 coexistence state, with the longer‐term aspiration of recovering submerged macrophyte‐dominated communities. Synthesis and applications . Findings move beyond the polarized historical vs. novel ecosystem debate by advancing a dynamic restoration pathway and targets for macrophytes. This pathway presents the Anthropocene baseline as a pragmatic stepping stone towards long‐term recovery and offers managers phased, realistic targets that sustain ecosystem services while keeping the operational historical reference as an aspirational goal. The method established offers a practical basis for developing effective restoration strategies and can be applied to Lake Liangzi and similar shallow lakes. It directly informs global freshwater restoration under the UN Decade on Ecosystem Restoration.