Quantifying the nonlinear factors of urban shrinkage: A case study in Heilongjiang Province, China

With urbanization, urban shrinkage has become a more prevalent and severe global problem. Although many studies have explored it, most of them lack precision, and the complex nonlinear causal mechanisms of urban shrinkage are still poorly understood. Therefore, based on the background of the transformation of traditional industrial cities in China, this research selects Heilongjiang Province as a typical case study and quantify the spatial pattern of shrinking cities. Furthermore, from a nonlinear relational perspective, the complex mechanism of urban shrinkage is revealed by using LightGBM. The results show that the area experienced a large-scale comprehensive shrinkage and severe shrinkage in some areas, while also generating scattered population clusters. In addition, the economic and industrial structure are still the most influential factors for population change, and the industrial structure transformation is still the main obstacle for its development. The research results are conducive to elevating the awareness of urban shrinkage in industrial cities and providing some theoretical guidance for sustainable development.