Hydrological connectivity modulates grassland degradation effects in the yellow river source region - Meng Zhou; Shu Guo; Liyuan Ma; Kening Zhang; Danni Zhou; Qiang Liu; Youqing Yang; Xiuzhu Sun; Yanbin Hao; Xiaoyong Cui; Jianqing Du; Yanfen Wang (Journal of Soils and Sediments, 2026)