Understanding the nonlinear trade-off relationship to optimize urban-rural ecosystem services: a case study in arid and semi-arid region, China

In arid and semi-arid regions, the potential for ecosystem service trade-offs creates challenges for sustainable ecosystem management due to the spatially varying ecological characteristics along the urban-rural gradient. However, the nonlinear dynamics of these trade-offs remain poorly understood. In this study, five key ecosystem services were assessed—carbon sequestration, food production, water yield, soil retention, and windbreak and sand fixation, using remote sensing inversion and ecosystem assessment models. The production possibility frontier (PPF) framework was introduced to systematically examine the heterogeneity in nonlinear trade-off relationships across urban, urban-rural fringe, and rural areas in Inner Mongolia from 2000 to 2019. The results showed that all ecosystem services increased to varying degrees, while five out of ten pairs of ecosystem services exhibited significant trade-offs. The highest trade-off intensity occurred between soil retention and windbreak and sand fixation service, with values of 0.52 in rural area and 0.64 in the urban-rural fringe. Notably, trade-off relationships and intensities varied across spatial contexts and the strongest trade-off intensity observed in urban-rural fringe areas. Our study introduces a novel PPF-based framework to explicate heterogeneous nonlinear trade-off relationships along the urban–rural gradient and underscores the significance for targeted policy interventions adapt to these spatial differences in arid and semi-arid regions, thereby advancing theoretical insights for coordinating urban–rural development globally.