Ecological compensation in the Beijing-Tianjin-Hebei region based on ecosystem services flow.

Under a background of unbalanced regional economic development and ecological environments, the accurate identification of ecological compensation (EC) areas and the determination of compensation standards have become research key and hotspots. Their aim is to improve the long-term mechanisms of interregional EC. In this study, ecosystem services value (ESV) in the Beijing-Tianjin-Hebei region (BTH) in 2000, 2010 and 2019 are calculated using modelling and ecological economics methods. The region is divided into ecological output and input areas according to ecosystem services supply and demand. The breakpoint formula and field strength model are introduced to reveal the characteristics of ecosystem services flow (ESF) from output areas to input areas. By integrating a transfer correction coefficient system of natural, economic and social factors, an EC model based on ESF is constructed, and EC amounts for the BTH are calculated. The results are as follows: (1) The ESV of the BTH shows an increasing trend, with little change in spatial distribution characteristics. The high-value areas are distributed in the Taihang and Yanshan Mountains and Bashang Plateau in the northwest, while the low-value areas are concentrated in the Southeast Hebei Plain. (2) ESF mainly occurs in the western and northern regions of the BTH. Output areas are mainly distributed in the Taihang and Yanshan Mountains and Bashang Plateau, and their number is increasing. The flow radius, flow intensity and ESV transfer amounts also show increasing trends. (3) The ratio of EC paid by Beijing, Tianjin and Hebei is 1:0.2:2.56, the EC amounts are all provided to the Hebei Province, and the funds mainly flow to Chengde City, Zhangjiakou City and Baoding City. The proposed EC model based on ESF provides a basis and reference for the construction of an inter-regional EC mechanism in the BTH.