Does Regional Urbanization Promote Balanced Land Development? Evidence from Long Time Series Satellite Imagery

Abstract

The urban megaregion has been promoted as among the major urbanization forms in New-Type Urbanization in China, which aims to promote more balanced development among cities and between the urban and rural areas in a region. While numerous studies have examined developed land expansion in cities worldwide using remotely sensed imagery, fewer have investigated its dynamic process in a rural area and the differences in the growth magnitude and expansion morphology between urban and rural areas. Using Landsat imagery from 1986 to 2020, we examined the spatiotemporal patterns of developed land in both the urban and rural areas in the Changsha–Zhuzhou–Xiangtan urban megaregion, China, using morphological analysis. We found that (1) the differences in the growth magnitude between the urban and rural areas varied between the different-sized cities, with increases in the largest city of Changsha, but decreases in the smaller ones of Zhuzhou and Xiangtan, although there was a slight increase at the megaregional scale. (2) The dynamic process of developed land in rural areas was similar to that in urban areas but showed a clear time-lag effect, where the dominant expansion types in urban areas shifted from edge to infilling expansion and to another edge expansion in 1986–2000, 2000–2010, and 2010–2020, whereas that in rural areas changed from outlying to edge expansion in 1986–2000 and 2000–2020. (3) The positive relationships between the growth speed and outlying and edge expansion suggested that the CZT urban megaregion was in the rapid outward expansion stage. Such a pattern may cause similar ecological effects, such as habitat fragmentation and urban heat archipelagos, to that in the eastern megaregions. Understanding such differences and their changes in the urban and rural areas will help optimize the strategies of urban megaregion sustainability.