Ecological conservation redline delineation in flood detention areas: A case study in Anxiang County, Yangtze River Basin, China

Abstract

Ecological conservation redline (ECRL) is a rigorously defined regulatory boundary established within critical zones, including ecological functional areas, ecologically sensitive regions, and vulnerable areas. It serves as the foundational threshold for preserving the ecological security of both national and regional contexts. Flood detention areas constitute a pivotal facet within the realm of ecological functionality. The delineation of ECRL boundaries for these flood detention areas aims to optimize the ecological structural composition, augmenting their capacity to provide ecosystem services. This endeavor holds profound implications of practical significance. However, there is currently a lack of methods for delineating ECRLs in flood detention areas. To address the above problem, taking Anxiang County in the Yangtze River Basin of China as an example, this study establishes a regional flood regulation service evaluation method through in-depth investigation and analysis of the ecosystem in the area. The method considers the importance of the evaluation of five ecosystem services, including flood regulation, water conservation, soil conservation, biodiversity conservation, and carbon sequestration. Based on these evaluations, the ECRL for Anxiang County is ultimately determined, with the area of 198.62 km2, accounting for 18.12% of the total area. Additionally, from the perspective of ecosystem service spatial transfer, a quantitative study is conducted on the ecosystem service radiation effect of the ECRL in Anxiang County, estimated to be approximately 1,462 million CNY. Overall, this study provides a theoretical basis for delineating ECRL in flood detention areas and developing corresponding ecological compensation systems for the watershed.