Dynamic simulation of landscape ecological risk in Gansu’s farming-pastoral ecotone based on topographic gradients - Yang, Le; Yan, Jixuan; Li, Guang; Ma, Weiwei; Li, Tao; Gao, Pengcheng; Li, Qiang; Yao, Xiangdong; Li, Jie; Wang, Wenning (Frontiers in Environmental Science, 2025)