Coupling coordination analysis and prediction of multi-social-ecological subsystem in the Xiaoxing'an Moutains-Sanjiang Plain, Northeast China

The Xiaoxing'an Moutains-Sanjiang Plain is currently facing environmental deterioration, economic recession, social development obstruction, population loss, which has been seriously affecting local sustainability. Considering that their solution often requires holistic approaches, which can involve multiple aspects of social-ecological system (SES), it is significant to clarify the evolution of coupling relationship among the subsystems of SES, to identify the obstacle factors that affect the coupling coordination degree (CCD) among them, and to predict the changing trend of their CCD. Basing on the collected panel data, this study established a metrics system to evaluate the CCD among environmental, economic, social, and population subsystems of five prefecture-level cities in the Xiaoxing'an Moutains-Sanjiang Plain. The dynamic laws and characteristics of the CCD were analyzed in spatial and temporal dimensions. The key factors hindering CCD were determined by using obstacle diagnosis model, and the future CCD was predicted based on Bayesian model. It is found that the evaluation values of the environmental, social, and population subsystem as well as the CCD at the region scale showed a fluctuating upward trend, in which the evaluation value of the environmental subsystem increases the most, while the evaluation value of the economic subsystem showed a downward trend; The CCD of 5 cities in studying areas showed different trends of development, and the CCD of Jiamusi City always ranked first, indicating that the CCD of the non-resource-based city with a large population and high GDP tends to be higher than that of other cities; The CCD of 5 cities is spatially "high in the plain area, low in the mountainous area", and the barycenter of the high CCD area gradually shifted from the northwest to the northeast during the study period; Total volume of foreign trade, total volume of actual use of foreign capital, number of college students per ten thousand people, total retail sale of consumer goods, and harmless treatment rate of domestic garbage are the main obstacle factors metrics for most cities; Environmental state, environmental governance, living standards, opening up, social stability, and population quality are the main obstacle factors at the observation dimension; According to the prediction results, except for Qitaihe, the CCD of other cities in the next 20 years showed a downward trend, and the CCD of Hegang showed the largest decline range and speed. Findings of this study may have important implications to long-term planning and policy formulation for promoting sustainability of the Xiaoxing'an Moutains-Sanjiang Plain and other similar areas.