Incorporating Stepping Stone Establishment into Rural Ecological Security Pattern Optimization: A Water–Energy–Food Coupling Perspective

Protecting ecological sources and restoring ecological stepping stones (ESSs) are key to constructing ecological security patterns (ESPs) in small-scale rural areas. Ecosystem services (ESs) associated with Water–Energy–Food (W-E-F) influence the ecological security of rural areas. However, how to construct rural ESPs to enhance the synergy and connectivity of W-E-F systems remains unclear. This study thus proposes a framework of rural ESP construction and optimization based on the coupling coordination analysis of ESs related to W-E-F, including Water yield, Carbon storage, and Food production. Using the Changsha–Zhuzhou–Xiangtan Green Heart region as a case, it identifies ecological sources and corridors through the coupling coordination degree (CCD) model and circuit theory. Moreover, it optimizes the ESP by incorporating the optimal ESS plan to improve source connectivity. The results show 14 ecological source patches covering a total area of 86.73 km² and 117.21 km of ecological corridors. Three ESS plans are evaluated, with Option II proving optimal, increasing corridor length by 31.02% and source connectivity by 57.10%, which is based on the high CCD of three ESs. The “One Core, Three Zones, Four Corridors, and Multiple Points” scheme was defined as the ESP. This study underscores the significance of small-scale ecological restoration and advocates a shift from a “single ES” to a “coupled ESs” perspective. And it offers new insights aiming to enhance the source connectivity from the “patch–corridor–matrix” paradigms to the “patch–stepping stone–matrix” framework. It also provides feasible suggestions for balancing ecological protection and resource sustainability in rural areas.