Research on Ecological Compensation Based on Ecosystem Service Flow: A Case Study in Guangdong Province, China

Ecological compensation (EC) is not only an essential tool for correcting the externalities of ecosystem services (ESs) and fostering sustainable development but also a crucial means to alleviate poverty and promote balanced development across regions. Based on the ecosystem service flow (ESF) theory, this article presents a universal framework for screening ESs in EC research, and employs multiple models and multisource data to measure the supply and demand of five ESs. Moreover, this study examined the transfer values of air-mediated ESs (AMESs) and water-mediated ESs (WMESs) using the field strength model and flow allocation method, respectively, due to their significant differences in flow direction, flow rate and attenuation characteristics. The results indicate that: (1) there is a significant disparity between the supply and demand of the five ESs in Guangdong, with the scope and extent of the mismatch varying among the different ESs. Generally, deficit areas are located in the central urban regions of the Pearl River Delta (PRD) cities and cities in eastern and western Guangdong. (2) The transfer values of all the surplus areas of the AMESs and WMESs to their corresponding deficit areas are 37.02 billion yuan and 37.43 billion yuan, respectively, accounting for 62.9% of the AMESs supply value in the study area and 2.5% of the output value of the WMESs in the surplus areas, indicating that a significant amount of the output value has been transferred to areas outside of the study area. (3) The total transfer in/out value between surplus and deficit areas is 71.83 billion yuan, and is economically acceptable for deficit areas. (4) Compared with the results of this study, some economically developed regions with high ecosystem service value (ESV) outputs in Guangdong have not been compensated, and the current EC standard is relatively low. We suggest that Guangdong pilot horizontal EC, explore various market-oriented trading systems, and increase vertical EC standards and enrich EC methods. This study provides a reference for the quantification of ESFs with different transmission carriers and the improvement of EC policy in Guangdong.