Rapid urbanization in a mountainous landscape: patterns, drivers, and planning implications

Abstract

Understanding patterns and drivers of urbanization is essential for urban sustainability, but such understanding is lacking for mountainous regions. This study had three objectives: (1) to quantify the spatiotemporal patterns of urban expansion in Chongqing, the largest mountainous metropolitan area in China, during 1990–2015; (2) to explore major drivers for the observed urbanization patterns; and (3) to identify the spatial signatures of Chongqing’s urbanization which differ from those of topographically flat urban regions for sustainable urban planning in mountainous regions. We used multiple metrics to characterize urbanization patterns and expansion modes. Pearson correlation analysis and Classification and Regression Trees (CART) were used to identify potential drivers. The built-up area of Chongqing increased five times during 1990–2015 with regional variations. Three growth modes—leapfrog, edge-expansion, and infilling, took place concurrently, but their relative dominance varied in time and space with leapfrog as the dominant mode in recent years. The major drivers of built-up area expansion changed from demography to economy, with topographic constraints attenuating over time. Compared to flat urban regions in China, the spatial signatures of Chongqing’s urbanization were characterized by greater dominance of leapfrog expansion mode with smaller and more regularly-shaped patches. The unique patterns and drivers of urban expansion in Chongqing provide new insights of urbanization in mountainous regions for sustainable urban planning. We have proposed a conceptual urban planning framework for mountainous cities based on landscape sustainability science, GeoDesign, and regional landscape characteristics.