Ecological security pattern construction and network resilience in agro-pastoral transition zones

As a typical agro-pastoral ecotone and ecological transition zone, the Bashang region of Hebei Province plays important ecological functions in water conservation and spatial connectivity of biodiversity, while exhibiting high sensitivity to climate change and human activity disturbances. However, due to long-term overexploitation, the regional ecological environment is fragile and still faces severe ecological degradation challenges such as grassland degradation and land desertification. Addressing single-perspective limitations of traditional ecological security pattern (ESP) construction, a multi-model ensemble was coupled with a structure-function-coupled complex-network resilience assessment method. A four-dimensional dynamic optimization framework, "Source Identification-Multi-criteria Decision-making-Corridor Simulation-Network Resilience" (SMCR), was proposed within this comprehensive approach. The SMCR framework dynamically optimizes ecological networks through the sequential "identification-weighting-simulation-evaluation" process, transcending static approaches. This framework, based on long-term time-series data, enables dynamic identification of ecological sources, construction of resistance surfaces, and simulation of multi-period ecological security patterns. By selecting the optimal conservation scenario through the OWA model and incorporating both random and targeted attack simulations to assess network resilience, it more accurately reflects regional ecological changes. The key findings were as follows: (1) OWA-driven scenario analyses spanning 2000-2023 revealed marked fluctuations in the optimal conservation area. Scenario 8 consistently demonstrated the best performance across the four benchmark years, highlighting its long-term robustness in synergistically enhancing the four ecosystem services (ESs). In contrast, Scenario 9 and Scenario 10 yielded the optimal results for 2005 and 2010, respectively. (2) From 2000 to 2023, the ecological sources exhibited a fluctuating trend of initial decline, followed by an increase, and then a subsequent decrease, with a cumulative net reduction of 6.9% compared to the 2000 level. Conversely, ecological corridors count and total length first increased and then decreased. Ecological sources were evenly distributed, centrally and southeast-dense yet sparse in the west and northeast. The northwestern region demonstrated high ecological resistance. (3) The resilience of the ecological network exhibited a persistent decline in its capacity to withstand disturbances, demonstrating particular vulnerability to targeted attacks. Critical-node removal triggered catastrophic collapse in network connectivity, underscoring their profound control of overall connectivity. Consequently, targeted zoning regulations were proposed, providing guidance for optimizing ecological security patterns in arid agro-pastoral transition zones.