Biogeochemical Nitrogen Cycling Versus Phosphorus Stoichiometry in Temperate Wetland Restoration: A Comparative Evaluation of Nutrient-Driven Macrophyte Community Assembly Trajectories

Abstract

Wetland restoration strategies frequently diverge on whether nitrogen (N) or phosphorus (P) dynamics serve as the primary lever governing macrophyte community reassembly. This study conducted a paired-catchment comparative analysis across twelve restored temperate freshwater wetlands in Central Europe and East Asia, quantifying N:P stoichiometric ratios, denitrification potential, and phosphorus sorption capacity over a 36-month chronosequence. Redundancy analysis and structural equation modelling revealed that P-limitation thresholds exerted stronger directional control over late-successional macrophyte functional trait composition, whereas N-loading governed early colonisation rates. Sediment redox gradients acted as a confounding modifier of both nutrient pathways. These findings challenge the prevalent N-centric paradigm in eutrophication management and provide quantitative benchmarks for adaptive nutrient-targeting protocols in temperate wetland restoration planning.