Assessment of long time-series greening signatures across the urban-rural gradient in Chinese cities

Greenery is a critical referent for assessing the health and sustainability of urban ecosystems. However, distinct urbanization pathways of cities can be accompanied by complicated encroachment or regeneration of green spaces, thereby leading to certain spatiotemporal diversity in greening signatures at both local and regional scales. Here, this study conducted a long-term (2000-2020) case analysis to evaluate the greening signatures and responsible drivers across the urban-rural gradient of Chinese cities. The major results showed that 1) Most case cities showed general but uneven greening trends. However, the urban-rural gradient shows a Sandwich pattern, i.e., the greening rate is significantly higher in developed and rural areas than in developing regions. 2) Climate change, especially temperature variation, performs as the dominant driver responsible for local greening, followed by anthropogenic-induced landscape alterations. 3) Especially, greening process in urbanized regions was more sensitive to climatic perturbations and less responsive to landscape changes over time, while that in rural regions was relatively stable. In the context of overall greening in Chinese cities, one should be aware of the uneven greening progress along the urban-rural gradient to proactively address the potential challenges of future climate and landscape changes for sustainable urban development.