Integrating ecological correlation into cellular automata for urban growth simulation: A case study of Hangzhou, China

Abstract

Rapid urbanization leads to a disorder land use pattern, posing severe threats to natural resources with high-quality ecosystem service (ES), hence, it is necessary to delineate ecologically constrained urban growth boundary (UGB) for containing sprawling urban expansion. The ecological constraint based on the assessment of specific or comprehensive ecosystem function provides little information about how the ecological correlation within different ESs affecting urban growth probability. This paper defined the strictest conservation with the least cost of total ES value as ecological constraint through excluding ESs trade-offs areas from potential urban development area, and the ecological constraint was further integrated into cellular automata (CA) to develop the ES-CA model for acquiring a win-win simulation between urban development and natural environmental protection. The case study of Hangzhou was implemented for the model application. Equivalent ES value was adjusted by spatial difference assessment to evaluate and visualize ES. Spearman correlation coefficient was adopted to retrieve the relation mechanism among different ESs and extract ESs trade-offs areas. Two alternative scenarios whether conserving the ESs trade-offs areas were established to investigate the unique advantages of the ES-CA model over the traditional ecological constraint-based CA. The comparative analysis using habitat quality and landscape metrics indicated that the urban growth pattern where the ESs trade-offs areas were prohibited for construction performed more effective in reducing habitat degradation, promoting land use compactness, and controlling sprawling urban expansion. According to the win-win scenario, the UGB having a polycentric spatial structure was delineated. In contrast with the planned UGB determined by socio-economic development policies, the proposed UGB demonstrated that the ES-CA model could play a more important role in growth management for ecological fragilely developing regions.