Multiscenario Simulation and Prediction of Urban Green Space in the Changle District of Fuzhou City, China, Based on Multiobjective Optimization and a GeoSOS-FLUS Model

Green spaces in densely urbanized areas along China’s southeast coast generally face spatial competition between ecological protection and development intensity, as well as conflicts between policy-oriented and market-driven values. Among them, Changle District in Fuzhou City, as the core area of the coastal new city, needs to coordinate its green space system to address complex three-dimensional problems. To explore the optimal configuration of green spaces under different ecological constraints and achieve a balance between ecological, economic, and social benefits, this paper takes Changle District in Fuzhou City as the research area, with 2020 as the base year, and innovatively combines a multiobjective optimization model with the Geographic Simulation and Optimization System–Future Land Use Simulation (GeoSOS-FLUS) model. The former is used to balance multiple objectives such as ecological conservation, economic development, and social needs, generating optimal allocation schemes. The latter precisely simulates the dynamic evolution of green spaces based on these schemes. Together, they overcome the limitations of traditional models, which cannot account for economic and ecological benefits when simulating complex urban land use. Based on this model combination, this paper simulates and predicts the area structure, spatial configuration, and target benefits of green space in Changle District in 2030 under ecological high-, medium-, and low-constraint scenarios. The results reveal the following: (1) In terms of area structure, the area of cropland and unused land in the three scenarios is smaller than the current value in 2020, while forest land and grassland have increased, water has been effectively protected, and construction land has gradually increased as ecological constraints have been relaxed. (2) In terms of spatial distribution, the area of cropland in the north, west, and central parts of the study area decreased significantly in all three scenarios. At the same time, the increase in forest land and grassland was concentrated in the north and west, and the rise in water was focused on the central part of the study area. The area of construction land in the south and west decreased slightly under the ecological high- and medium-constraint scenarios. At the same time, it increased around the center of the study area under the low ecological constraint scenario. (3) From the perspective of target benefits, under the high-ecological-constraint scenario, the ecological benefits and economic benefits are 4.122 and 94.545 billion yuan, respectively, which is a significant increase compared with the ecological benefits in 2020, while the economic benefits have slightly decreased. Under the medium-ecological-constraint scenario, the ecological and economic benefits are 4.067 and 104.023 billion yuan, respectively, representing significant increases compared with 2020. Under the low-ecological-constraint scenario, the ecological benefits and economic benefits are 4.009 and 112.945 billion yuan, respectively, which represents a slight increase in ecological benefits compared to 2020 but a significant increase in economic benefits. The conclusions of this study can be applied to urban green space planning practices, providing comprehensive support for decision-makers in formulating scientific and reasonable green space allocation strategies under different ecological constraints and helping to achieve sustainable urban development goals.