Spatiotemporal Changes of Land Ecological Security and Its Obstacle Indicators Diagnosis in the Beijing-Tianjin-Hebei Region

Land ecological security (LES) is a cornerstone of sustainable development, and the study of the LES evaluation has become a hot field in the LES problems. The coordinated development of the Beijing-Tianjin-Hebei (BTH) region is one of China's national development strategies. With the development of urbanization and industrialization, the conflicts between people and land in this area are increasingly prominent, and there are large regional differences in land ecological quality. To evaluate the land ecological security (LES) of this region, an evaluation index system is constructed based on the pressure-state-response (PSR) framework model, and the entropy-weighted TOPSIS method is applied to calculate the LES index. Then, the spatio-temporal changes of LES in the BTH region from 2007 to 2018 are analyzed. In addition, we adopt an obstacle degree model to analyze the obstacle indicators. The results show that the LES of the BTH region increased from 0.1934 to 0.3284 during 2007-2018, and the LES level increased from the dangerous level (I) to the critical level (III). Despite the improved LES in all areas in the BTH region, there were different trends (high in the central area, relatively low in the northern and southern areas). We identified seven obstacle indicators and discussed different development strategies. Our findings will provide guidelines for land use management and offer references for the coordinated development of the BTH region.