Investigating the Impact of Urbanization on Water Ecosystem Services in the Dongjiang River Basin: A Spatial Analysis

Abstract

The expansion of urban areas has resulted in a substantial increase in demand for water ecosystem services. To address this issue, this study aims to investigate how the interaction between urbanization and water ecosystem services changed in response to different levels of urbanization in the Dongjiang River Basin from 1985 to 2020. The research examines four water ecosystem services (water yield, soil retention, and water purifications of N and P) and three types of urbanizations (population urbanization, economic urbanization, and land urbanization) to identify spatial heterogeneities among developed urban areas, developing urban areas, and rural regions, as well as their dynamic interactions. The findings indicate that water ecosystem services and urbanizations tend to be spatially polarized, with high values downstream and low values upstream. Although they have become more closely aligned, there is a local mismatch under basin-level homogeneity. Urbanization has migrated and centralized in a southward direction, while water ecosystem services have moved westward. This difference of migration results in an increasing trade-off in the west band of Dongjiang River. In particular, the developing urban area has been strengthening the function of the transition zone between the developed urban area and rural area, resulting in a dramatic decrease in synergy. The synergy of the rural area dominates the increasing synergy of the entire basin, but the developed urban area tends to lower the water ecosystem services that lag behind urbanization. The study recommends that policymakers consider different urban levels when developing urbanization plans and water resource management strategies, and implement measures to maintain the synergy in the rural area and mitigate the trade-off in the developing area.