Trade-offs between wetland resistance and recovery and thresholds in their responses to climate extremes

Wetlands are increasingly exposed to intensifying droughts, floods, and rapid hydrological transitions under climate change, yet their stability responses remain poorly quantified. We developed a multidimensional assessment framework that integrates the structural indicator Normalized Difference Vegetation Index (NDVI) and the functional indicators Gross Primary Productivity (GPP) and Water Use Efficiency (WUE), combined with generalized additive models, to evaluate wetland resistance and recovery across a spectrum of extreme hydrological events in the NaoLiRiver wetlands group, China. Results revealed marked asymmetry: droughts induced high resistance but low recovery, whereas floods produced the opposite pattern. Functional indicators such as GPP and WUE consistently showed lower resistance but faster recovery than NDVI, highlighting their higher sensitivity to disturbance and earlier recovery onset. Rapid drought-flood or flood-drought transitions amplified resistance but sharply reduced recovery, suggesting compounded legacy effects that constrain recovery. Resistance and recovery exhibited hump-shaped relationships with event intensity, peaking at extreme intensity thresholds of -0.73 ± 0.08 for drought and 0.90 ± 0.05 for flood before collapsing under more extreme conditions. These findings provide quantitative thresholds and mechanistic insights into wetland stability trade-offs, offering actionable guidance for adaptive management under escalating hydrological extremes.