Rapid urbanization in the lower Yellow River basin has greatly contributed to the socio-economic development of Northern China, but it has also exacerbated land use/land cover change, with significant impacts on ecology. Ecological quality is a comprehensive spatial and temporal measure of an ecosystem’s elements, structure and function, reflecting the ecological state under external pressures. However, how land use/land cover change affects the ecological quality during urbanization has rarely been explored. In this study, Jinan, a megacity in the lower Yellow River basin, was taken as a typical region, and the response of ecological quality to the land use/land cover change in 2000, 2010 and 2020 was retrieved using the remote sensing ecological index. For the mixed land use/land cover change types, a type-decomposition and spatial heterogeneity quantification method based on the abundance index was proposed, and the impact mechanisms of the land use/land cover change on the ecological quality were revealed by coupling with GeoDetector. The results show that: (1) Farmland and built-up areas, as the dominant land use/land cover types, were the primary factors controlling the spatial pattern of ecological quality. (2) Urban expansion and farmland protection policies resulted in the transfer of farmland and woodland to built-up areas as well as the transfer of woodland and grassland to farmland, which intensified the degradation of ecological quality. (3) Ecological protection policies prompted the transfer of farmland and grassland to woodland and the transfer of farmland to grassland as the main cause for the improvement of ecological quality. (4) Although ecological protection and urban development were implemented in parallel, uneven land use/land cover changes resulted in a 1.4 times expanded area of poorer ecological quality with increasingly serious spatial agglomeration effects. This study can provide scientific references for the ecological conservation and high-quality, sustainable development of cities in the lower Yellow River basin.

Urbanization has significantly impacted ecological connectivity, making the optimization of ecological networks (ENs) crucial. However, many existing strategies focus on overall network structure and overlook the spatial concentration of local ecological processes flow (EPF), limiting the effectiveness of ecological planning. This study proposes a novel EN optimization framework based on urban–rural gradient spatial zoning to enhance connectivity from the perspective of EPF. The framework divides areas outside the core urban zone (CUZ) into the urban fringe zone (UFZ), urban–rural interface zone (UIZ), and natural rural zone (NRZ), applying tailored optimization strategies in each zone. These strategies include increasing corridor redundancy, reducing corridor resistance, and expanding corridor width to alleviate EPF concentration. Using Jinan, a mega-city in China’s Yellow River Basin, as a case study, this study simulated EN changes over 20 years and validated the framework’s effectiveness. Optimization validation showed that increasing ecological land in low-flow corridors to 65% in the UIZ and expanding NRZ corridors to 5 km improved connectivity by 6.3%, addressing seven pinch points and three barrier points. This study highlights the importance of optimizing ENs via urban–rural zoning to support sustainable development and ecological protection policies.

Constructing ecological networks (ENs) is an effective measure to mitigate the conflict between urban development and ecological conservation. However, existing simulating methods lack adequate consideration of human ecological demands and the spatial scale differences between these demands and natural ecological processes. This might lead to issues such as incomplete ecological process cycles or structural mismatches being overlooked during ENs simulations. To address these gaps, this study proposed an urban multi-scale nested ENs simulating framework that integrates human ecological demands with natural ecological processes. The framework first simulated an ENs focused on natural ecological process cycles at a global scale (GS). Then, it simulated an ENs centered on human ecological needs within the core urban areas at local scale (LS). Finally, it nested these multi-scale ENs by using cross-scale ecological supply sources as connecting points. This framework was applied to simulate spatio-temporal pattern changes in ENs of Jinan City, a core city in downstream of the Yellow River in China, aiming to mitigate cross-scale ecological conflicts between human–nature interactions under the background of urbanization. The study’s findings revealed that the area of demand sources increased by 8.56 times over 20 years. the area of cross-scale supply sources decreased by 15 km² relative to 2000, and the deterioration in connectivity was more pronounced in GS compared to LS, with a decline of approximately 13.8%. These changes indicate the presence of incomplete ecological process cycles and structural mismatches across the multi-scale boundaries within the study area, which have been worsening annually. We recommend optimizing Jinan City’s multi-scale ecological network through three key strategies: rectifying internal structural mismatches, protecting core ecological areas, and aligning regional ecological demands. Implementing these strategies could significantly improve the network structure, reduce cross-scale mismatches, and enhance ecological connectivity by about 9%. This study highlights the importance of addressing structural mismatches and promoting complete ecological cycles in urban multi-scale ENs simulating, providing valuable insights for formulating urban multi-scale ecological conservation and restoration policies.