The Evolution and Driving Mechanisms of the Blue-Green Space Publicness Pattern in Changsha, China

Abstract

Urban blue-green space (UBGS), where public life occurs, is vital for social interaction, social cohesion, public spirit cultivation, and community formation. UBGS publicness reflects whether it supports and facilitates community formation. From the perspective of the man–land relationship, UBGS with high publicness should have three significant characteristics: accessibility of elements, functional selectivity, and structural connectivity and shareability. This study took Changsha as the case study and evaluated its UBGS publicness in 2012, 2016, and 2020. We analyzed the evolution of the UBGS publicness pattern, and the results indicated the following: (1) The elements accessibility indicator showed a decreasing trend year by year and maintained the pattern of low in the city center and high in the suburban area; (2) the functional diversity indicator changed from a monocentric polarized spatial pattern to a polycentric and balanced spatial pattern; (3) the structural connectivity indicator generally improved and showed the core-edge pattern; and (4) the comprehensive indicator showed that the pattern developed from the core edge to the core edge as the primary focus with fan-shaped expansion supplemented. Based on this, combined with Changsha’s urban development history, environmental, policy, economic, and social factors supported, led, promoted, and guided the formation and evolution of the UBGS publicness pattern. This study improved the theoretical foundation of UBGS publicness, provided ideas and methods for the UBGS publicness evaluation on the urban scale, and may provide a reference for the construction of livable and sustainable cities.