Integrating ecosystem services and landscape connectivity to construct and optimize ecological security patterns: a case study in the central urban area Chongqing municipality, China.

Rapid urbanization is often accompanied by the irrational utilization of natural resources and environmental degradation. Ecological security pattern (ESP) is an effective way for rational allocation of resources, which is conducive to achieving sustainable development. Taking the central urban area Chongqing municipality as the study area, ecological sources were identified by integrating ecosystem services and landscape connectivity. Combining natural and anthropogenic factors, a resistance surface was constructed and modified, and four ecological function zones were determined. Ecological corridors were extracted and prioritized by Linkage Mapper and the gravity model, and ecological nodes were also obtained. A network connectivity assessment was performed to compare the connectivity of ESPs before and after optimization. The results showed that ESPs included 2453.72 km2 of ecological sources, 189 ecological corridors, 69 ecological nodes and 4 ecological function zones. The ecological sources primarily consisted of forestland, cultivated land and water bodies in Jinyun, Zhongliang, Tongluo, Mingyue and other mountainous areas, with the maximum distribution index value at the tenth level of the terrain niche index gradient. The Yangtze River and Jialing River were also the most important ecological sources. Ecological corridors were mainly dominated by forestland and cultivated land. Ecological nodes were concentrated in Yubei, Banan and Jiulongpo districts. The optimized ESPs had higher network connectivity and closure, with a more uniform distribution of ecological corridors, and included 2461.95 km2 of ecological sources, 218 ecological corridors and 72 ecological nodes. Finally, recommendations for sustainable development were proposed. This study provides a theoretical reference for decision-making related to ecological protection and urban planning.