Impact of construction land transition on staple crop diversity in China

Construction land transition (CLT) under rapid urbanization persistently alters regional land-use patterns, significantly affecting cropland allocation and agricultural production structures. As a critical indicator of safeguarding food security, staple crop diversity (SCD) is both essential for preserving biodiversity and for balancing its relationship with sustainable urbanization, yet its impact by CLT has been overlooked. To address this gap, we examined the influence of CLT on SCD across China from 2000 to 2020 by employing bivariate spatial autocorrelation and the spatial error model with lag dependence (SEMLD). The three most widely planted staple crops (rice, wheat, and maize) were selected, and levels of CLT and SCD were quantified by using multi-source spatial data. The results found that China's CLT levels rose from 0.097 to 0.126 during the study period, with a spatial distribution that decreased from east to west. Meanwhile, SCD increased gradually from 0.186 to 0.204, with the central region experiencing the most notable growth. The high SCD was observed in the east and low in the west, with high-value areas primarily concentrated in China's grain-producing regions. The rise in CLT corresponded with reduced SCD: Every 1% increase in CLT led to a national average 0.14% decrease in SCD, whereas heterogeneity analysis identified distinct spatial variations in the impact, characterized by an east-negative and west-positive pattern, and the negative impact was increasingly expanding. This study provides scientific insights for creating regionally differentiated control policies to optimize China's construction land transition, facilitating the coordination of protecting diverse staple food cropping systems and achieving effective land-use governance.