Impacts of the Grain for Green Program on ecosystem resilience in northern China

Under climate change, ecosystems are increasingly exposed to multiple disturbances and stresses. Ecological engineering is widely regarded as an effective strategy for protecting and restoring ecosystems; however, whether such interventions enhance ecosystem resilience remains unclear. This study evaluates the impact of the Grain for Green Program (GFGP) on ecosystem resilience in northern China. Ecological engineering and policy timing were identified using long-term land-cover trajectories. Ecosystem resilience was quantified using lag-one autocorrelation (AR(1)) derived from detrended satellite-based vegetation index time series and evaluated using a staggered difference-in-differences approach. The results show divergent patterns among restoration types. Grassland restoration is associated with a broader spatial extent of declining AR(1) and a sustained post-treatment reduction, indicating stable and persistent resilience gains. In contrast, forest restoration exhibits a non-linear response. Although AR(1) initially decreases after implementation, it increases during the middle and later post-treatment periods, implying a potential long-term decline in resilience. In terms of overall effects, cropland-to-grassland conversion exhibits a statistically significant overall increase in resilience, whereas the average treatment effect of cropland-to-forest conversion is not statistically significant. These findings improve understanding of how large-scale ecological engineering impacts ecosystem resilience and provide evidence to inform more effective climate change mitigation and adaptation policies.