Can urban compactness improve ecosystem services: Evidence from Chinese urban agglomerations

The construction of compact cities has been proposed to effectively avoid a series of ecological, environmental, and socioeconomic issues caused by extensive and sprawling urban development while establishing an efficient and resource-saving urban development mode. Identifying the spatial variations and interaction relationship between ecosystem services (ESs) and urban compactness can provide valuable knowledge for the construction of compact cities and the pursuit of high-quality development. Nevertheless, it remains unclear whether the urban compactness of Chinese urban agglomerations (UAs) is conducive to the promotion or inhibition of ESs at the county scale. This study aimed to address the research gap by examining the spatial relationship between ESs and urban compactness using a set of spatial regression models. Grain yield (GY), habitat quality (HQ), and carbon storage (CS) were selected to measure ESs in this study. Our findings revealed that the urban compactness of UAs in China generally increased from 2010 to 2020, with the most significant increases observed in the Yangtze River Delta, Mid-Yangtze River, and Central Plains UAs. The GY and HQ's global Moran's I for urban compactness were significantly negative, while that between CS and urban compactness was significantly positive in 2010 and negative in 2020. The results of the spatial regression analysis indicated that there was a negative association between urban compactness and ESs in both 2010 and 2020. Additionally, the negative impact of urban compactness on HQ increased, while the effect on CS diminished. The negative effect of urban compactness on ESs was strongest at the regional-level UAs, followed by national and local levels. The results of the geographically weighted regression model indicated that the impact of urban compactness on ESs varied spatially. This study provided a scientific reference for further optimization of compact urban development and the conservation of ESs.