Ecosystem service supply–demand ratio zoning and thresholds of the key influencing factors in the Pearl River Delta, China

Context

Human demand for natural resources continues to increase owing to climate change and population growth. The supply capacity of ecosystem services has also declined drastically, posing a severe threat to the long-term sustainability of human society.

Objectives

Taking the fast-urbanized Pearl River Delta (PRD) as the study area, the specific research objectives of this study were to intuitively reveal the spatial distribution of ecosystem service supply–demand relationships in rapid urbanization and explore the dominant influencing factors and their impact process on ecosystem service supply–demand relationships.

Methods

It zoned the ecological space based on the ecosystem service supply–demand ratio (ESSDR) evaluated by six typical ecosystem services. And then, the Geographical Detector model, Structural Equation Modeling and regression analysis were used to explore the ranking and threshold effects of influencing factors of ESSDR.

Results

(1) From 2000 to 2020, the ESSDR in the central PRD deteriorated, whereas the ESSDR in the remote areas of the PRD was further optimized. Stable grading eigenvalues of the ESSDR were found based on cumulative frequency curves from 2000 to 2020. (2) Green density (GD) and land development size (LDS) were the dominant natural and social factors influencing ESSDR in the PRD, respectively. (3) There were two thresholds in the impact process of GD (21% and 66%) and LDS (8% and 54%) on the ESSDR, which matched the gradients of urban, developing urban, and rural areas.

Conclusions

There are certain thresholds in the ESSDR responding to land use change. The focus should be on the imbalance in areas with GD < 21% or LDS > 54% and protective measures should be strengthened in areas with GD > 66% or LDS < 8%.