Ecosystem services balance and its influencing factors detection in China: A case study in Chengdu-Chongqing urban agglomerations

Rapid urbanization in China's urban agglomerations has severely disrupted the relationship between supply and demand for ecosystem services (ESs). Exploring the spatial and temporal variation characteristics of ESs balance and its driving mechanisms is crucial for the high-quality development of urban agglomerations. However, few studies have explored the pattern of ESs balance and its driving mechanisms at multiple scales in urban agglomerations, which constrains the formulation of regional ecological protection and land use policies. In this study, we attempted to characterize the ESs balance pattern and its spatio-temporal variation from 2000 to 2020 at multiple scales in the Chengdu-Chongqing urban agglomerations (CCUA), using ESs matrix and hotspot analysis tools. We then introduced the optimal parametric geographic detector to detect the formation mechanism of the spatial differentiation pattern of ESs balance. The results show that the overall ESs supply index for CCUA was greater than the demand index. The ESs were in short supply in Chengdu and Chongqing. The pattern of ESs balance had significant scale dependence. The hot spots of the ESs balance index were mainly in the western, southern, and eastern mountainous regions, while the cold spots were concentrated in urban areas of Chengdu and Chongqing, with significant differences in characteristics at different scales. The spatial distribution of the ESs balance was mainly affected by the forest land proportion, slope, normalized difference vegetation index (NDVI), elevation, cultivated land proportion, and temperature. The interaction of natural, land use, and socio-economic factors significantly enhanced the spatial differentiation of ESs balance. The interaction of different types of factors highlights the importance of topography, NDVI, cultivated land, forest land, and population. The results of this study can provide scientific references for the sustainable management of ESs and the construction of ecological civilization in CCUA.