Horizontal ecological compensation standards based on ecosystem services flow

The determination of compensation standards is the core of horizontal ecological compensation (HEC). However, existing studies focused on the ecological value stocks of ecosystem services (ESs) within an administrative area but ignored their spatial mobility when determining standards, so the HEC policies had difficulty in achieving the desired goals. This study takes the upper-middle reaches of the Yangtze River as the study area, adopts the gravity model to calculate the ecosystem services flow (ESF) in the eight provinces of the area, and formulates a HEC standard accounting model to determine the compensation standards. The results show that there are inhomogeneous distributions of ESs supply and demand from 2005 to 2020. The ESs supply tends to decline, then increase, whereas the demand continuously increases. The total ESF volume from the ESs-providing areas (ESPAs) to the ESs-benefiting areas (ESBAs) first increases and then decreases. In 2020, Tibet, Qinghai, Chongqing, and Hunan are the ESPAs, with Qinghai obtaining the highest compensation standard of 308.56 million CNY and accounting for more than 50% of the total. The ESBAs include Sichuan, Yunnan, Hubei, and Jiangxi, among which Sichuan is the main source of HEC funds with payments of 375.79 million CNY. This study can provide theoretical references for improving HEC rationality, as well as resolving the contradictions between environmental protection costs and benefits externalities for large-scale regions.