Dynamics of ecosystem services in response to urbanization across temporal and spatial scales in a mega metropolitan area

Research on the relationship between ecosystem services (ESs) and urbanization has been drawing attention in recent years. We analyzed the relationship between ESs and urbanization in the Pearl River Delta (PRD) region, and explored whether and how this relationship changes across temporal and spatial scales. The InVEST model was used for ESs mapping and various urbanization indicators were selected. Correlation analysis and curve estimation were used to detect the linear and nonlinear relationships between ESs and urbanization. Results of the study indicated that regulating and supporting services decreased, while provisioning services increased with urbanization. Significant correlations (p<0.05) were found between ESs and urbanization, and mostly presented an increasing trend from 2000 to 2018 and from the grid scale to the county scale. Curve estimation indicated that regulating and supporting services decreased as urbanization increased, and water yield service increased as urbanization increased, while the relationship between food provisioning and urbanization presented an inverseU shape. Generally, the relationships between ESs and urbanization varied with different ESs but remained relatively robust across time and scale. This study specifies the impact of urbanization on ESs, and highlights the importance of spatial scales in studying the relationship between urbanization and ESs.