Resilience of the large-scale ecological restoration: How water matters?

Large-scale ecological restoration has gained recognition as a promising nature-based solution for addressing global environmental and societal challenges. The Three-North Shelterbelt Forest Program (TNSFP), the world's largest ecological restoration project in China, has achieved considerable ecological and social benefits. However, its long-term resilience and sustainability remain subjects of scientific debate and public concern. Here, we explored vegetation resilience trajectories and their relationships with water budgets across the program region from 2001 to 2022, and projected future vegetation suitability through 2050 (i.e., the end of the TNSFP) by integrating meteorological observations, remote sensing data, and outputs from global circulation models. We found that 48.2% of the vegetation exhibited declining resilience, particularly in forested areas, despite widespread greening across the TNSFP region. Vegetation resilience strengthened against the increase in productivity within the water resource carrying capacity, but the relationship reversed once productivity surpassed water availability limits. Notably, forest resilience peaked under conditions of full precipitation utilization, whereas grassland resilience reached its lowest point when water supply and demand were balanced. By 2050, approximately 6.5% of the study area is projected to face degradation risk, with an additional 22.2% potentially at risk. Our findings emphasize the importance of water resource availability for vegetation resilience and stability, laying a scientific foundation for sustainable ecological restoration strategies.