Evolution of farmland landscape fragmentation and its driving factors in the Beijing-Tianjin-Hebei region

Farmland landscape fragmentation has become one of the main manifestations of global land use changes during the last century. Since the reform and opening-up in China, the Beijing-Tianjin-Hebei region, as the represen-tative region in China, has exhibited a continuous process of farmland landscape fragmentation. Scientifically revealing the spatiotemporal dynamics of farmland landscape fragmentation is of great significance for sus-tainable land management. Although the characteristics of farmland landscape fragmentation have been widely studied, measuring the dynamics of farmland landscape fragmentation from the perspectives of landforms and urban-rural variations remains poorly understood. This study relies on the comprehensively theoretical models to spatiotemporally identify farmland landscape fragmentation and applies a comprehensive index method that includes ArcGIS, FRAGSTATS landscape pattern analysis and the multiscale geographically weighted regression model to empirically analyse the spatial-temporal characteristics of farmland landscape fragmentation in China from 1980 to 2020. The results indicate that the value of the farmland landscape fragmentation index in the Beijing-Tianjin-Hebei region is characterised by process of 'slight increase-rapid decrease-continuous increase'. High farmland landscape fragmentation index values were observed in the northern and western Beijing-Tianjin-Hebei regions. Moreover, significant differences in farmland landscape fragmentation were observed under different macro landforms. The farmland landscape fragmentation index in the mountainous regions is much higher than in the plains. Furthermore, as the distance to Beijing's centre increases, the farmland landscape fragmentation index decreases in suburban and peri-urban areas. Finally, the results also reveal the driving factors of farmland landscape fragmentation. The results showed that the natural environment is always the crucial driver of farmland landscape fragmentation. Besides, social activities play an important role in the past, but economic development has a more significant coefficient these days. The findings of this study not only verify that the proposed theoretical framework is valid and provides a reference for future policy measures to protect farmland but also provide a basis for farmland landscape fragmentation from a multiscale perspective by, more precisely, identifying the heterogeneity of drivers.