Monetized Estimates of the Ecosystem Service Value of Urban Blue and Green Infrastructure and Analysis: A Case Study of Changsha, China

Urban blue-green infrastructure (BGI) forms the basis of a regional ecosystem. Quantitative calculations can identify the weak points of a typical ecological environment, which is helpful for providing a basis for the spatial planning and ecological environment protection of developing cities. Currently, assessment of BGI ecosystem services focuses on local temperature, climate, and entertainment aesthetics, and the integrity of ecological indicators needs improvement. The assessment is usually conducted within large blue-green areas such as parks and rivers, and street greening is typically ignored. Roof gardens and unmanaged blue-green spaces also have ecosystem service functions. Therefore, our study aimed to extract the basic design distribution of urban blue-green spaces more accurately and monetize the value of its ecosystem services. Changsha, one of the top ten ecologically competitive cities in China, was the research focus. First, four types of BGI, forest, grassland, wetland, and waterbody, were extracted using remote sensing images and ArcGIS10.8. Second, the adjusted value coefficient was used to quantify the service value and geographic spatial distribution of the four BGI ecosystems in monetary terms. The results showed that in 2020, the total economic value of ecosystem services (ESV) generated by BGI in the study area was CNY 36.25 billion. Among ecosystem services, forest land climate regulation and waterbody hydrological regulation accounted for the largest proportion, at CNY 6.543 and 15.132 billion, respectively. The urban center had the weakest climate regulation capacity, and the Xiangjiang River Basin had the strongest hydrological regulation capacity. The urban center had the lowest ESV, thus requiring the attention of urban planners in the future. This study evaluated and optimized the distribution of BGI in Changsha according to the ESV of the existing BGI to help improve the ESV of the city center and create a green, ecological, and healthy city.