Submerged Macrophyte Coverage and Composition: Key Regulators of Buffering Capacity and Resilience in Freshwater Ecosystems to Nutrient Pulses

ABSTRACT Climate change is driving more frequent extreme rainfall events, which in turn trigger nutrient pulse events. These events can degrade water quality and reduce biodiversity in receiving water bodies. While submerged macrophytes are critical for stabilising aquatic ecosystems during such nutrient pulses, differences in macrophyte composition and coverage may affect their functional effectiveness. This study simulated nutrient pulse events by conducting in situ mesocosm experiments to investigate the effects of different macrophytes composition (single‐species community [ Vallisneria natans ] vs. multi‐species community [ V. natans + Hydrilla verticillata + Potamogeton wrightii ]) and coverage levels (0%, 30%, 40%, 50% and 60%) on system buffering capacity and stability. Additionally, we identified the coverage thresholds required for stabilising aquatic ecosystems under pulse loading conditions. Higher submerged macrophyte coverage significantly reduced TN, TP, Chl‐a concentrations and water turbidity, with a critical threshold of 50% macrophyte coverage for optimal nutrient pulse mitigation. Compared with mixed communities, monocultures of V. natans showed better nutrient buffering capacity, with TN and TP removal efficiencies increased by 1.93 and 1.49 times at 50% coverage. Selecting appropriate submerged macrophyte coverage and suitable community compositions is crucial for improving ecological restoration efforts, especially in reducing nutrient disturbances and maintaining long‐term aquatic ecosystem stability.