How to quantify the impact of urban expansion on ecological security in Northwest China

Rapid urbanization poses a serious threat to regional ecological security (ES) and has led to significant ecological losses. To assess and mitigate ecological security (ES) losses caused by urban expansion, this study simulated urban expansion patterns in Northwest China by 2050 under the Shared Socioeconomic Pathways and Representative Concentration Pathways (SSP-RCP) scenarios. A coupled ERI (Ecological Risk Index)–EH (Ecological Health)–ESs (Ecosystem Services) model was employed to quantitatively analyze the regional ES development levels under different scenarios. From the perspectives of landscape pattern dynamics and ecological degradation, the study evaluated the impacts of urban expansion on ES across various development modes. Scenario comparisons were then used to implement ES zoning control strategies. The results reveal that while the northwest and southeast regions show relatively high ES levels, a gradual decline is observed towards central areas. The Economic Priority Development (EPD) model enhances urban land cohesion and mitigates landscape trade-offs on ES. Among the three scenarios, the ranking of ES loss areas is: EPD > Business as Usual (BAU) > Ecological Priority Protection (EPP), with the EPD scenario causing 2.524 times more ecological loss than the EPP scenario. Using provincial, municipal, county, and ecological function zones, the optimal urban development plan is selected based on the highest ES potential. This study provides strategic guidance for spatial planning by offering a practical and scalable framework to reduce ecological degradation while promoting balanced and sustainable regional development.