Synergistic Enhancement of Carbon Sinks and Connectivity: Restoration and Renewal of Ecological Networks in Nanjing, China

Abstract

Urbanization has led to a reduction in green space, weakening the region’s carbon sink capacity and stability and bringing a series of ecological problems, making the restoration and improvement of the ecological environment crucial. This study used Nanjing, China, as a case to construct an ecological network by applying Morphological Spatial Pattern Analysis (MSPA) and the Linkage Mapper (LM) tool based on circuit theory. The connectivity of ecological patches was evaluated by calculating the delta potential connectivity index (dPC). The CASA model (Carnegie–Ames–Stanford approach) was applied to quantify carbon sequestration in Nanjing. We propose an innovative carbon sink index (CSI) that integrates three indicators: capacity, efficiency, and variability. This index assesses the carbon sink function of ecological patches from both static and dynamic perspectives. Using the Future Land Use Simulation (FLUS) model, we simulated carbon sequestration changes in 2035, providing insights for risk assessment and future optimization strategies. The results reveal a significant positive correlation between node connectivity and both carbon sink capacity and efficiency, indicating that enhancing connectivity at key nodes can effectively improve its carbon sequestration. On this basis, by coupling dPC and CSI indices to classify ecological network nodes, we proposed four strategies for optimization: ecological conservation, structural connectivity, carbon sink improvement, and synergistic enhancement. Finally, by adding 26 ecological stepping stones, 32 ecological corridors, and optimizing landscape components, we achieved dual improvements in both the structural and functional aspects of the ecological network. After optimization, the network connectivity increased by 1.6% and the carbon sink increased by 3.82%, demonstrating a significant improvement. This study emphasizes that by protecting, enhancing, and restoring ecological spaces, the carbon sequestration function and stability of urban ecological networks can be effectively improved. These findings provide valuable insights for the scientific management of ecological spaces in urbanized areas.

Keywords

• carbon sink index
• landscape connectivity
• ecological network optimization
• multi scenario simulation
• urban planning