Population shrinkage and cropland fragmentation in Northeastern China: Spatiotemporal associations and implications for land governance

Rural population decline and rapid ageing are reshaping agricultural regions, yet their implications for the reorganisation of agricultural land systems remain insufficiently understood. Focusing on Northeastern China, a major grain-producing region experiencing sustained out-migration and rural labour loss, we examine the relationship between population shrinkage and cropland fragmentation. Using demographic data and annual 30 m land-cover data for 320 county-level units from 2000 to 2020, we construct a comprehensive population shrinkage index (PS) and a multidimensional cropland fragmentation index (CLFI), and assess associations between PS and changes in CLFI using Spearman's rank correlation and bivariate spatial analyses. Population shrinkage was widespread and intensified over time: 93.13% of counties experienced shrinkage over 2000–2020, and 71.25% exhibited aggravating or recent shrinkage trajectories. Over the same period, the regional mean CLFI rose from 0.292 to 0.323, a 10.62% increase, with pronounced temporal and spatial heterogeneity. The association was non-significant during 2000–2010 but became significantly negative during 2010–2020 (ρ = −0.34), indicating that stronger population shrinkage increasingly coincided with reduced fragmentation intensification in the later period. Spatial analyses further revealed significant negative associations at the decadal scale, while local patterns became more spatially organised after 2010 and remained regionally differentiated. These findings suggest that population shrinkage should not be understood as a direct or uniform driver of cropland fragmentation, but as an important demographic condition within broader processes of rural land-system adjustment. Therefore, farmland protection and rural land governance should account for regional differences in cropland adjustment under demographic change.