Construction and optimization of multi-scale nested ecological security pattern in the context of territorial space planning in Dongting Lake Ecological Economic Zone.

The construction of multi-scale ecological security patterns, as a crucial spatial approach for coordinating ecological protection and economic development, is of great significance for ensuring the integrity, adaptability, and sustainability of regional ecosystems. In the context of the reconstruction of the territorial space planning system, we assessed the construction and optimization of 'regional-municipal-urban' multi-scale ecological security pattern across the Dongting Lake Ecological Economic Zone (regional scale), Changde City (city scale), and the central urban area of Changde City (urban scale), integrating interdisciplinary methods such as minimum cumulative resistance model, ArcGIS spatial analysis, and circuit theory. The results showed that the conduction efficiency of ecological sources in the study area presented a characteristic of scale-decay. The regional-municipal scale coupling degree decreased by 20.1% compared to the municipal-urban scale, and among them, 15 ecological sources became spatial connection blank areas during cross-scale conduction. The conduction efficiency of ecological corridors was low due to insufficient cognition of multi-values. Among the 18 cross-scale ecological corridors, only four achieved effective connection, and 14 potential ecological corridors required priority restoration to enhance connectivity. The conduction efficiency of key ecological nodes attenuated due to insufficient scale correlation. There were four and five common ecological pinch points at the regional-municipal and municipal-urban scales, respectively. 16 common ecological barrier points formed cross-scale barrier zones. We employed a 'pattern identification-nesting diagnosis-collaborative optimization' full-process analytical framework to propose a targeted optimization scheme based on identifying potential problems in the foundational pattern, and ultimately constructed a multi-scale nested ecological security pattern comprising 38 ecological sources, 52 ecological corridors, and 158 ecological nodes. Our results would provide important theoretical support and practical guidance for the ecological protection and restoration, optimal allocation of land resources, and smart management of the ecosystem in the Dongting Lake Ecological Economic Zone.