<p>Wetland restoration has been widely documented to improve vegetation structure and habitat conditions, yet the environmental associations with food-web trophic structure remain insufficiently understood. Here, we compared natural and restored wetlands in the Sanjiang Plain, China, to examine associations between water quality conditions and food-web structure. Compared to natural wetlands, restored wetlands generally showed enriched δ¹³C signatures in several basal resources and consumers, while δ¹⁵N patterns varied among basal resources and fish species. In addition, dietary contributions differed between wetland types, with consumers relying primarily on particulate organic matter (POM) in natural wetlands (34.20% ± 15.00%) and on phytoplankton in restored wetlands (30.52% ± 5.00%). Restored wetlands also showed higher trophic redundancy, as indicated by reduced MNND. By contrast, restored wetlands exhibited shorter food-chain length, lower trophic diversity, and reduced isotopic niche width (SEAc). Partial least squares regression (PLSR) analysis revealed that environmental change index (ECi) values were significantly correlated with food-web metrics. Both Pearson correlation analysis and variable importance in projection (VIP) results indicated strong associations between environmental variables and trophic diversity, trophic redundancy, and isotope niche. Key environmental factors, screened based on VIP values (&gt; 1), were identified in descending order as: chemical oxygen demand (COD, 1.17), turbidity (1.16), dissolved oxygen (DO, 1.14), and total nitrogen (TN, 1.11). These results demonstrate close associations between water quality conditions and food-web trophic structure in natural and restored wetlands, highlighting the value of integrating water quality and stable-isotope-based food-web indicators when assessing wetland restoration outcomes.</p> Graphical Abstract <p></p>