Half a century of adaptive governance on marginal and degraded lands sustains agriculture-ecology-economy co-benefits in an estuarine delta energy city of China

Marginal and degraded lands in coastal areas have essential ecosystem functions and thus have experienced intensive exploitation over the past half-century. However, the responses of the agriculture-ecology-economy nexus (AEEN) to natural and human disturbances and their drivers and interactions remain insufficiently understood, thereby constraining coordinated environmental governance. Thus, this study performed a case study of Yellow River Delta City, which contains China’s highest delta wetland cover and has a long history of energy development, to examine the regime shifts of AEEN sectors and their interactions within a social-ecological system framework by a combination of biophysical models and socioeconomic statistics. Coastal development promoted built-up area expansion and substantial cropland occupation, while regime shifts in water-sediment dynamics increased the complexity of the delta’s morphology and geometric characteristics. Climate warming and fluctuating precipitation promoted vegetation greening and enhanced biomass accumulation, whereas soil loss remained stable. Economic growth, particularly due to the increasing importance of the tertiary industry, created sufficient employment opportunities. However, the inappropriate urban-rural industrial structure (i.e., over-reliance on energy industry) and low employment and livelihood diversity in rural areas led to population loss and industry transfer. Planting structure adjustments characterized by the expansion of economic crop (i.e., cotton) sown area from 2000 to 2013 temporarily reduced grain productivity. This reversal of the co-benefits between pairwise AEEN sectors during 1978–1999 and 2014–2023 resulted in trade-offs for the period 2000–2013. The findings regarding regime shifts of nexus sectors and their drivers and interactions offer valuable lessons for balancing the multiple dimensions of AEEN sectors and enhancing the adaptability of deltas to changing social-ecological contexts. Such insights may help optimize the efficacy of catchment-adaptive governance and sustain co-benefits for AEEN sectors worldwide.