Construction and optimization of ecological security patterns in Dryland watersheds considering ecosystem services flows

The establishment of ecological security patterns (ESPs) has emerged as a significant approach to address the inherent conflict between ecological preservation and economic advancement. Existing studies commonly only focus on the supply of ecosystem services (ESs) but pay little attention to the demand for ESs and less attention to ecosystem service flow (ESF), which leads to the limited satisfaction of ecological space planning with the needs of human society. This study takes the West Liao River basin as an example to design a comprehensive ecological security pattern construction and optimization method. This study quantified the supply and demand of soil conservation (SC), carbon fixation (CF), water purification (WP), windbreak and sand fixation (WS) and water provision (FW) five key ESs in the study area from 2000 to 2020, and discussed the construction and optimization strategy of the ESPs from the perspective of “supply-flow-demand”. The results indicated that a total of 25 ecological source areas have been identified, with an optimized total area of 3.57×104km2, with 53 ecological corridors, including 15 primary corridors, 38 secondary corridors, 31 ecological checkpoints, and 16 ecological obstacle points. Based on the spatial distribution of ecological sources, an ecological security pattern of “four zones, three belts, and multiple branches” has been constructed. The distribution of ecological sources in the watershed is mainly on the forest and grassland in the northern, central, eastern, and southwestern regions, ecological pinch points is predominantly observed in the central and western regions, and the first-class ecological corridors are predominantly located in the western region. Research has shown that there is a mismatch between the supply and demand of ecosystem services within the study area. The use of the “supply-flow-demand” framework can more accurately identify ecological sources that traditional methods have not been able to identify. This research finding will contribute to enhancing the comprehension of the ecosystems within the West Liao River basin. This study aims to explore and optimize the construction methods of ESPs, which have certain universality and reference value, and can provide new paths and decision support for the construction of future regional ecological security patterns.