The responses of ecosystem services in coastal cities to urbanization in 30 years: A case study of Qingdao City, China

Coastal urban areas play a pivotal role in regional economic growth, yet they are also sensitive regions where the natural environment interacts with human activities. Rapid urbanization has led to ecological issues, such as the degradation of key ecosystem services (ESs) in coastal cities. Understanding the impact of urbanization on the supply and demand of ESs in coastal cities is crucial for ensuring the healthy and sustainable development of the socio-economy in these areas. This study takes the coastal city of Qingdao as a case study, with a focus on the supply and demand relationships of seven key ESs—carbon sequestration, food production, habitat quality, recreational capacity, soil retention, water yield and marine aquaculture—as well as their responses to population growth, economic development, and spatial expansion, which are three distinct aspects of urbanization. The findings indicate that: (I) From 1992 to 2022, the evolution of different ESs exhibited variability, all displaying notable spatial imbalances. (II) During this period, the urbanization process in Qingdao had a pronounced negative effect on the supply and demand of ESs. Spatial urbanization had the most significant impact on carbon sequestration, food production, habitat quality, water yield, and marine aquaculture, while population urbanization most notably affected recreational capacity. (III) The sensitivity of different types of ESs to population, economic, and spatial urbanization varies. Carbon sequestration, food production, recreational capacity, soil retention, water yield, and marine aquaculture were most sensitive to economic urbanization, whereas habitat quality was most sensitive to spatial urbanization. This research provides a basis for decision-making in the sustainable development and comprehensive management of coastal cities and their ecosystems.