Spatial characteristics and influencing factors on population shrinkage in city-town-rural areas of small and medium-sized cities in China

As China's population flows towards megacities and urban agglomerations, population shrinkage (PS) has become an actual challenge that many small and medium-sized cities (SMSCs) have to face directly. However, most of the existing studies treat SMSCs as a homogeneous whole, and comparative analyses of PS in different types of SMSCs need to be strengthened. Based on this, this study used data from the 2010 and 2020 censuses to analyze the spatial characteristics of PS in city-town-rural areas of SMSCs, and identify the influencing factors affecting PS of SMSCs through Elastic Net regression. The study finds that: (1) the PS of SMSCs occurred in towns and rural areas outside urban areas, with 43.2% and 96.2% of SMSCs experiencing PS in towns and rural areas, respectively. (2) SMSCs' PS has significant difference in urban scales, and the degree of PS in SMSCs increased with the downscaling of city size. (3) The spatial distribution of PS in city-town-rural areas are different - the PS in city area is observed in the three provinces of Northeast China and the eastern part of Inner Mongolia, the PS in town area shows the characteristics of “large dispersion and small concentration”, and the PS in rural areas is widely spread in the vast majority of SMSCs. (4) The influencing factors of PS in SMSCs are diversified, and their effects are different according to the scale level, administrative level and regional distribution of the city. This study is conducive to the exploration of urban development laws in the era of negative population growth, and can provide valuable references to guide the optimal layout of the urban system in the new development stage and promote the high-quality development of SMSCs.