Identification and distribution characteristics of recessive hydro-ecological space in the Qinhuai River Basin, China

Context Currently, many cities face conflicts between hydro-ecological space and non-ecological land types characterised by intense human activities. The delineation of hydro-ecological space remains ambiguous and requires further clarification. Aims The scientific identification of regional hydro-ecological space and the analysis of their distribution characteristics are crucial for planning hydro-ecological space and addressing hydro-ecological issues such as flood disasters, water pollution, and water resource shortages. Methods With the Qinhuai River Basin in China, as the research area, the ArcGIS software and the InVEST model were used to identify the regional recessive hydro-ecological space, visualise three types of recessive hydro-ecological space, i.e. water conservation space, water purification space and soil and water conservation space, and quantitatively analyse the spatial distribution characteristics of each hydro-ecological space. Key results The results indicated that recessive hydro-ecological space accounted for 47.59% of the total area of the Qinhuai River Basin, primarily concentrated in the south-western and eastern regions of the basin. Furthermore, the key areas of water conservation space, water purification space, and soil and water conservation space accounted for 50.58, 51.37 and 54.39% respectively. Conclusions The results indicated that recessive hydro-ecological space accounted for 47.59% of the total area of the Qinhuai River Basin, primarily concentrated in the south-western and eastern regions of the basin. Implications These findings showed the conflict between the current land-use patterns and hydro-ecological space in the Qinhuai River Basin. In subsequent stages, non-ecological land types within hydro-ecological space can be re-planned to effectively protect hydro-ecological space and mitigate hydro-ecological security risks.