[Construction of Urban Green Infrastructure Based on a Multi-scale and Multi-objective Approach in Ecologically Vulnerable Areas in the Upper Yellow River： A Case Study of the Four Lakes Hydrographic Net in Ningxia].

The construction of urban green infrastructure （UGI）， especially in ecologically vulnerable areas of the upper Yellow River， is an effective tool to ensure ecological protection and promote high-quality development of the Yellow River Basin. Taking the Four Lakes Hydrographic Net in Shizuishan City as an example， this study focused on identifying the important sources of UGI by morphological spatial pattern analysis （MSPA）， which integrated both regional and inter-regional perspectives. Additionally， the UGI networks were constructed based on multiple objectives， using the minimum cumulative resistance （MCR） model， and the UGI network stability， integrating centrality and connectivity perspectives， was subsequently evaluated. The study produced several results： ① Nineteen important sources， with an area of 105.07 km²， were identified in the Four Lakes Hydrographic Net， and 41 important sources， with an area of 433.10 km²， were recognized in Shizuishan City. Both the intrinsic importance of each patch and the connectivity between patches were considered in the integration of UGI sources. ② Based on a trade-off analysis and synthesis of each single object， lengths of 7.79 km of critical corridors， 9.42 km of ordinary corridors， and 29.89 km of fragile corridors did not need to be maintained. Furthermore， 5.51 km of ordinary corridors and 25.78 km of fragile corridors did not need to be upgraded. The overall connectivity index （O_G） value of the UGI network under the multi-objective approach exceeded the same index under the single-object approach and the simple overlay of an individual object. It not only ensured the integrity of the landscape pattern but also saved costs of landscape construction. The method of multiple scales and objectives in UGI planning reveals the diverse requirements for urban landscape security and sustainability. It can be applied to carry out urban landscape protection and restoration according to different geographical conditions， and it also provides a valuable example for addressing similar areas.