Optimization of ecological security patterns considering both natural and social disturbances in China's largest urban agglomeration

With little consideration of both natural and social disturbance in previous studies on Ecological security patterns (ESPs), the identification of conservation priority areas is not accurate enough to enhance the structure and quality of the ecosystem for regional ecological security. To address this gap, this study developed a novel framework of "importance-connectivity-disturbance " to identify ESPs, selecting the Pearl River Delta (PRD) as the study area. Ecological sources were identified by combing ecological importance and landscape connectivity. A more integrated ecological resistance was developed to represent natural and social disturbance, and applied to obtain levels of regional ecological security. Ecological corridors were then extracted and classified using the minimum cumulative resistance (MCR) model and gravity model. The results showed that 9645.77 km(2) of ecological sources and 72 potential ecological corridors were determined, and the region with the higher security grade accounted for 19.18% of the entire area. The optimized ESPs of "one ring, two cores, three zones, and four axes " was developed based on key components of ESPs and local socioeconomic conditions. This study provides a novel perspective on the methodology of identifying ESPs and an essential reference for ecological protection and regional development planning in urban agglomerations.