Does High Population Density Inhibit the Ecosystem Service Value in China’s Large Cities? An Economic Explanation

Ecosystem service value (ESV) is a central concern in geography and ecology. An in-depth analysis of the relationship between population agglomeration and ecosystem service value holds significant importance for achieving the sustainable development goal of human-land harmony. This paper constructed a theoretical model of the relationship between population density and land-averaged ESV in 35 large Chinese cities between 2005 and 2020. The study used multiple data sources and combined fixed effects with interaction terms and instrumental variables to measure the spatiotemporal evolution characteristics of ESV and land-use policy zones and investigate the effect of population density on land-averaged ESV, along with its underlying explanatory mechanisms. The results are as follows: 1) regarding the spatiotemporal evolution of ESV and land-use policy zones, the land-averaged ESV decreased from 2005 to 2020, while the total ESV increased over the study period. Both the land-averaged ESV and total ESV were highest in western China, followed by eastern and middle China. 2) Population density theoretically had a nonlinear effect on land-averaged ESV, such as an ‘inverted U-shaped’ effect that first promoted and then inhibited; however, at this stage, a positive linear relationship was observed between population density and land-averaged ESV (i.e., population density significantly promoted land-averaged ESV, with a 1% increase in population density leading to a 0.62% increase in land-averaged ESV). 3) Regarding temporal differences, the effect of population density on land-averaged ESV increased over time. In terms of spatial differences, population density had a greater effect on land-averaged ESV in agricultural restoration and ecological enhancement zones. In addition, the effect of population density on land-averaged ESV was highest in middle China, followed by western and eastern China. 4) In the explanatory mechanism of how population density influences the land-averaged ESV, we found that population density can promote land-averaged ESV by enhancing the manufacturing level and reducing residential consumption levels. This study combines economics with ecology and geography, and the study findings may serve as a reference for other researchers and also provide policy suggestions for urban and rural planning.