Road-induced ecohydrological changes in peatlands: Long-term dynamics and controlling factors

The central Qinghai-Tibet Plateau, China. This study used the DigiBog_Boreal model to simulate 300-year peatland dynamics under road disturbance, assessing the individual and synergistic effects of peat oxic decomposition (αₒₓ), terrain slope, and net precipitation on long-term ecohydrological dynamics. Road construction causes an immediate (within one year) upslope water-table (WT) rise and a downslope drawdown. Both effects attenuate with distance, though the drawdown lasts 1–2 years. The downslope WT decline increases the water-table depth (WTD), which then recovers gradually over decades to centuries, regulated by site-specific factors. Specifically, a higher αₒₓ accelerates WTD recovery by enhancing aerobic decomposition and peat subsidence, which reduces hydraulic conductivity, limits drainage, and promotes WT rise. Gentler slopes minimize the initial WT decline, shrink the aerobic zone, thereby reducing peat loss and enhancing ecohydrological resistance. Increased net precipitation has limited effect in mitigating the initial decline but accelerates the subsequent WT rebound through added moisture, thereby improving system resilience. Multifactorial analysis reveals synergistic effects: combining elevated αₒₓ with high net precipitation enhances peatland resilience, while combining it with a gentler slope improves both resistance and resilience. Despite natural recovery, road disturbance induces irreversible changes in peat properties and diminishes long-term carbon storage, with a maximum simulated peat loss of 43 % by the end of the simulation period. • Roads disrupt peatland hydrology, triggering asymmetric water-table shifts with centennial-scale recovery. • Peat decomposition rate, slope and net precipitation jointly govern ecohydrological resistance and resilience post-disturbance. • Road-induced peat property alterations impair long-term carbon storage, despite natural feedbacks mitigating water-table declines.