Sustainability Evaluation on the Grain to Green Program in the Hexi Corridor of China: A Metacoupled System Perspective

Most previous studies aim to predict ecosystem sustainability from the perspective of a sole human or natural system and have frequently failed to achieve their desired outcome. Based on the coupled human and natural system (CHANS) and its interaction with other systems, we attempted to analyze the effectiveness of the Grain to Green Program and predict future trends in the Hexi Corridor, the hub of the ancient silk road of China. At different scales, we applied a metacoupling framework to investigate the flows, effects, and causes of the complex CHANS. Three typical inner river watersheds within the corridor at three different geographic scales (local, regional and national) were estimated and compared. The Telecoupling Geo App, additional models, and software tools were employed to evaluate the CHANS series of the focal system (Hexi Corridor, local), adjacent system (Gansu Province, regional), and distant system (China, national). The results showed that most flows can be screened and quantitatively analyzed across focal, adjacent and distant systems. The social and economic transformations in adjacent and distant systems could affect the possibility and whereabouts of labor transfer in the focal system. Moreover, the labor migration increased the implementation efficiency of the Grain to Green Program as a Payment for Ecosystem Services (PES) strategy, thereby improving its ecological benefits. For the first time, we established a metacoupled model to quantitatively evaluate aspects of ecosystem sustainability in China, providing insight to the theory and application of sustainability science.