Ecological redline delineation based on the supply and demand of ecosystem services

As the bottom line of safeguarding ecological security, the term "ecological redline", which was proposed in China, has important guidance and management value for maintaining ecological stability. The relationship between the supply and demand of ecosystem services (SDES) is a game between the supply side and the demand side of ecosystem services, reflecting the sustainability of ecosystem service functions and the harmony between the ecology and economy. Ecological redline is closely related to SDES. However, at present, the theoretical relationship between ecological redline and SDES has not been analyzed in depth, and the explanation in the "Technical Guidelines for the delineation of ecological protection redlines" (hereinafter referred to as "Guideline") is vague. This paper analyzes the relationship between ecological redline and SDES, and further emphasizes that the delineation of ecological redlines includes the consideration of the relationship between supply and demand of ecosystem services. The difference between the supply and demand of ecosystem services (ESr) was used to represent SDES. A systematic method called "ecological redline delineation based on the supply and demand of ecosystem services (ERDBESs)" was proposed, including the calculation of ESr, the analysis of land use conversion, the identification of the scope of ecological protection, and the map of the ecological redline with ArcGIS. Urumqi was taken as the case city to conduct ERDBESs. The results showed that the total area of the ecological redline of Urumqi is 1826.23 square kilometers (km2), accounting for about 12.9% of the total area, in consistent with the announced ecological redline of Urumqi. The results show that the ecological redline delineation method in the Guideline actually includes the consideration of SDES, and this study provides a demonstration for it. This study regarded the ERDBESs as a feasible and rational method to delineate ecological redline and can be used as the theoretical support for the Guideline to practise ecological redline delineation based on SDES, enhancing the policy implications of the Guidance regarding the implicit logic between ecological redline and SDES.