Spatiotemporal response of ecosystem service value in Jinan metropolitan area to urban expansion based on GTWR model

Objective As China’s urbanization enters a stage where central cities lead the development of metropolitan areas and urban agglomerations, how to promote the coordinated development of urbanization and ecological environment in metropolitan areas has become an important issue for high-quality urban development. Research about the spatiostemporal response of ecosystem services to urban expansion helps to characterize the spatial and temporal evolution of urban development and ecosystem services, promote the synergistic development of cities and ecosystems, and help formulate and implement sustainable planning strategies.

Method Taking Jinan metropolitan area as the target area, we studied the spatial and temporal characteristics of each city’s expansion based on the urban expansion index calculation, evaluated the ecosystem service value based on per unit area, and analyzed the temporal and spatial differentiation characteristics of ecosystem services. Furthermore, we studied the spatiotemporal response of ecosystem services to urban expansion of the Jinan metropolitan based on GTWR.

Result (1) From 1980 to 2020, urban expansion of the Jinan metropolitan area was characterized by time series and regional differentiation. The urban spatial expansion rate and intensity were sorted from high to low as small cities, large cities, megacities and medium-sized cities. (2) The overall ecological service value within the urban area was showing a decreasing trend year by year. The mainstream of the Yellow River, Dongping Lake and its surrounding areas, and mountainous area in central Shandong Province of eastern China were important areas with high value of ecosystem services. The proportion of synergistic relationship in metropolitan areas was slightly lower than that of trade-off relationship, with megacities accounting for the highest proportion. (3) Urban expansion in the Jinan metropolitan area had a negative impact on ecosystem services, while the intensity of negative effects decreased year by year. The impact of urban expansion on the functions of ecosystem services of different subcategories was significantly different. Specifically, urban expansion has a negative impact on supply services and support services, while the intensity of impact on supply services is increasing. Urban expansion has a positive impact on regulation services. The impact of urban expansion on cultural services has two sides and differs significantly in different areas.

Conclusion We clarify the distribution pattern of spatiotemporal variation of urban expansion of different cities in the Jinan metropolitan area, and further analyze the development state of gradual deterioration of ecosystem services during the study period. Based on the GTWR model, we quantify the different driving characteristics of urban expansion on ecosystem services at the spatial level. The results can provide a decision-making basis for the high-quality sustainable development of metropolitan areas.