Demographic trends in China's northeast borderlands: Shocks from core-periphery relations and border effects

Border regions are not only the geographical margins of national sovereignty, but also the vanguard to advance cross-border cooperation. Their demographic trend is shaped by the interplay of core-periphery dynamics and geopolitical relations, with distinct geopolitical contexts inevitably giving rise to divergent trajectories in borderland population development. Considering locational uniqueness, this paper explores the contributing factors of the spatiotemporal heterogeneity of population in China's northeast borderlands. The results indicate that the China-DPRK borderlands exhibited more pronounced trends of demographic decline compared to the China-Russia borderlands. Furthermore, in the China-Russia borderlands, depopulation and aging deteriorated with the increase in the distance from the border, while the opposite was true for China-DPRK borderlands. The decline of borderland population could be attributed overall to the siphon effect dominated by core-periphery relations. Nonetheless, in the China-Russia borderlands, the border effect exerted a positive influence on population development, particularly in regions with a robust industrial foundation and abundant financial resources. This spatial effect adhered to the distance-decay principle, which to a certain extent mitigated the adverse impacts of core-periphery dynamics. In the China-DPRK borderlands, the border effect projected a negative influence on population development, and its inhibitory effect was particularly pronounced in industrial regions. Spatially, this effect gradually diminished with the increase in the distance from the border, which reinforced the adverse impacts of core-periphery dynamics on borderland population trajectories. These findings can serve as a foundational basis to formulate targeted population development strategies and optimize the spatial arrangement of populations in border regions.