From Preservation to Transformation: Long-Term Locational Vitality Evolution and Multi-Scale Influencing Factors of Heritage Spaces in the Yangtze River Delta, China

Heritage spaces are gradually transforming from traditional conservation objects into dynamic resources that promote urban regeneration and regional development. However, their long-term vitality changes and associated influencing factors remain insufficiently understood. This study investigates national-level heritage spaces in the Yangtze River Delta, including national-level historic and cultural blocks, historic and cultural towns, and tourism and leisure blocks. An analytical framework integrating nighttime light remote sensing data, economic development indicators, population characteristics, and spatial location conditions was established to examined long-term locational vitality changes (as reflected by nighttime light intensity), spatial differentiation, and associated influencing factors of heritage spaces. The results show that (1) from 2000 to 2022, national-level heritage spaces in the Yangtze River Delta exhibited an overall significant increase in nighttime light intensity, indicating positive locational dynamism during the study period, although substantial differences existed among individual sites; (2) different types of heritage spaces demonstrated significantly different nighttime light change patterns, with spatial distributions showing clustering characteristics mainly concentrated in core urban areas; and (3) the evolution of locational vitality of heritage spaces was jointly influenced by economic conditions and population characteristics. A stronger service-oriented economic structure was associated with greater vitality enhancement, while population-related factors exhibited scale-dependent associations. County-level population density showed a negative relationship with vitality growth, whereas local population density around heritage spaces was not statistically significant, suggesting that population concentration alone does not necessarily guarantee vitality improvement. This study reveals the locational vitality transformation of national-level heritage spaces from conservation toward adaptive development, as reflected by nighttime light changes, from a long-term dynamic perspective and establishes a multi-scale influencing factor analysis framework, providing theoretical support and empirical references for the classification, adaptive utilization, and sustainable development of heritage spaces.