Maintaining and improving the connectivity of protected areas (PAs) is essential for biodiversity conservation. The Post-2020 Global Biodiversity Framework (GBF) aims to expand the coverage of well-connected PAs and other effective area-based conservation measures to 30% by 2030. We proposed a framework to evaluate the connectivity of PAs and developed strategies to maintain and improve the connectivity of PAs based on PA connectivity indicators, and we applied this framework to China’s terrestrial PAs. We considered that the concept of PA connectivity is at the level of both PA patches and PA networks, including four aspects: intra-patch connectivity, inter-patch connectivity, network connectivity, and PA–landscape connectivity. We found that among China’s 2153 terrestrial PA patches, only 427 had good intra-patch connectivity, and their total area accounted for 11.28% of China’s land area. If inter-patch connectivity, network connectivity, and PA–landscape connectivity were taken as the criteria to evaluate PA connectivity, respectively, then the coverage of well-connected terrestrial PAs in China was only 4.07%, 8.30%, and 5.92%, respectively. Only seven PA patches have good connectivity of all four aspects, covering only 2.69% of China’s land. The intra-patch, inter-patch, network, and PA–landscape connectivity of China’s terrestrial PA network reached 93.41%, 35.40%, 58.43%, and 8.58%, respectively. These conclusions indicated that there is still a big gap between China’s PA connectivity and the Post-2020 GBF target, which urgently needs to be improved. We identified PA patches and PA networks of ecological zones that need to improve PA connectivity and identified improvement priorities for them. We also identified priority areas for connectivity restoration in existing PAs, potential ecological corridors between PAs, and priority areas for PA expansion to improve the connectivity of PAs in China. Application of our framework elsewhere should help governments and policymakers reach ambitious biodiversity conservation goals at national and global scales.

Non-Technical Summary: As cities like Beijing expand rapidly, green and blue spaces (GBS)—essential for ecosystem services (ESs) such as clean air, flood control, and recreation—are increasingly threatened. This 20-year study examines how urban expansion and policy interventions have shaped Beijing’s GBS. While green initiatives have increased natural areas, unchecked urban sprawl has fragmented these spaces, reducing their environmental benefits. Satellite data and urban planning analyses underscore a key lesson: maintaining well-connected natural zones is critical for urban resilience. These findings are broadly applicable for rapidly growing cities globally, urging urban planners to integrate ecological conservation with development, and to safeguard healthy environments and vibrant communities. Technical Summary: This study quantifies the spatiotemporal dynamics of urban GBS in Beijing, evaluating their essential role in delivering ESs and strengthening urban resilience. Although China has achieved substantial progress in urban greening, the ecological impacts of rapid urbanization on GBS configuration and connectivity have not been comprehensively quantified. Using an integrated analytical framework combining principal component analysis and multiple linear regression, we reveal how urban development strategies have shaped GBS dynamics over two decades. A spatially explicit analysis, utilizing geographically weighted regression, further elucidates the heterogeneous relationships among the normalized difference vegetation index, human footprint index, and ESs delivery capacity. Notably, socioeconomic incentives and green infrastructure governance—especially objective indicators such as forest, garden, and greenspace area—have effectively driven GBS expansion. However, urban expansion has led to pronounced fragmentation of peri-urban GBS, suggesting potential degradation of their ecosystem service support functions. These findings emphasize the need for adaptive GBS management strategies that balance ecological conservation with sustainable urban growth in rapidly developing cities. Social Media Summary: Urban growth fragments green and blue spaces, reducing vital ecosystem services. Balancing conservation with development is essential for sustainable cities.