Linking ecological red lines and public perceptions of ecosystem services to manage the ecological environment: A case study in the Fenghe River watershed of Xi'an

Ecosystem services (ES) are used as a tool for eco-environment management, and this study establishes a framework that integrates ecological red line (ERL), public perceptions of ES and trade-offs among ES into regional eco-environment management. The public perceptions of ES are assessed using questionnaires and statistical analyses. Three models (InVEST, i-Tree Eco, ROS), a food supply calculation method and GIS are used to quantify eight ecological indicators (water yield, soil retention, water purification, biodiversity conservation, atmospheric regulation, outdoor recreation, food supply, and prohibited development zones) in the Fenghe River watershed (FRW). Three ecological function areas are delineated via the ERL standard, and the trade-offs among ES are assessed via correlation analysis. The results show the following: 1) the top five preferred ES by the public are atmospheric regulation, water purification, food supply, freshwater supply and outdoor recreation, and the local environment and individual demands are the main factors that affect preferences; 2) from 2000 to 2015, the quantity of the water yield, soil retention, Nitrogen output and biodiversity index slightly decreases, and the amount of the NO2 removal, food supply and outdoor recreation index slightly increases; 3) based on the Delimitation scheme for ERL of Xi'an, the FRW is divided into ecological redline zone (ERZ), ecological function important zone and ecological function general zone, and the ERZ accounts for the largest proportion (55.7%); and 4) inconsistent trade-offs/synergies among ES are observed in different ecological function areas. Based on these results, we establish a management framework and propose corresponding measures to improve ES for different ecological function areas. This multi-dimensional composite management framework can be used for planning or environmental management.