Abstract
With the rapid development of global urbanization, the single urban planning model is greatly restricted by the surrounding natural environment and economic and social structure. In this context, the urban agglomeration model was proposed, which refers to one or two megacities as the development core and multiple large and medium-sized cities as the auxiliary units, relying on the geographical space infrastructure connection, it forms multiple coordination between spatial planning and economic development and finally realizes the integration and cluster development. In 2005, the United Nations issued the , which believed that natural ecosystem is the "Life support system" of human beings and provides the necessary "Ecosystem services", and classified the service functions of natural ecosystem into four categories: supply, regulation, support and culture. Then, the evaluation of ecosystem service value has rapidly become one of the most important means to evaluate urban green natural resources. Therefore, the study of the spatial-temporal response mechanism of natural ecosystem services to the spatial expansion of urban agglomerations in the dimensions of time and space can effectively provide decision-making assistance for the overall urban ecosystem management and the rational and effective allocation of resources. Therefore, based on the perspective of spatial coupling, this paper chooses the most typical beijing-tianjin-hebei urban agglomeration as the research object. Based on the interpretation and analysis of its five satellite remote sensing data in 1980 to 2018, the spatial and temporal process of its urbanization expansion was located. Software models such as INVEST and CITYGREEN were used to measure the value evolution trend of its natural ecosystem under four categories of service functions: supply, regulation, support and culture, and using GI* index and the regression equation fitting on the response degree and correlation to the urbanization process of the beijing-tianjin-hebei urban agglomeration on the time dimension. Then, the bivariate spatial autocorrelation index is used to judge the response mechanism of its spatial dimension. Finally, the FLUS model is used to fit its future evolution trend and build the corresponding prediction and warning model. The analysis results show that: 1) From 1980 to 2018, the urban space level of the beijing-tianjin-hebei urban agglomeration has an obvious trend of expansion, with the urbanization space increasing from 15018 to 28,050 square kilometers, an increase of more than 86.78%. 2) From 1980 to 2018, the ecosystem service function deteriorated significantly, the total ecosystem service value decreased from 478.120 billion yuan to 451.918 billion yuan, a decrease of more than 5.48%. 3) Under the scale of the beijing-tianjin-hebei urban agglomeration, adjustment and support services show a significant correlation with urban space expansion, while supply and cultural services have weak spatial and temporal responses to urban space expansion. 4) Under the scale of the beijing-tianjin-hebei urban agglomeration, the negative spatial correlation between ecosystem service functions and urban expansion is clear, and the spatial characteristics of low in the north, high in the south, low in the outside and high in the middle. 5) According to the FLUS fitting model, simulate the spatial pattern of ecosystem service functions of the beijing-tianjin-hebei urban agglomeration in 2030, and make targeted early warning planning. This paper discusses the spatial and temporal response of natural ecosystem services to urban spatial expansion in the context of urban agglomeration, and constructs a response evaluation method and a prediction and early warning system, which is of great reference significance in the planning of the same type of city or urban agglomeration.
