Quantifying Critical Thresholds of Submerged Macrophyte Coverage to Buffer Climate-Amplified Ammonium Pulses and Stabilize Clear-water States

-N at low SMC increased macrophyte degradation risk. Structural equation modeling revealed that macrophytes-mediated nutrient competition and light stabilization underpinned these effects. Additionally, we identify a critical SMC threshold (39-51%) to mitigate pulse impacts─a finding urgently needed to guide lake restoration in a changing climate. This work bridges the gap between pulse ecology and adaptive management, offering actionable strategies for SDG 6 (Clean Water) and 13 (Climate Action).