Influencing mechanism of microtopography on erosion hydrodynamics on bare slopes of pika mounds in alpine meadows in the Yellow River source area, Western China

作者：Shengchun Tong, Guorong Li, Xilai Li, Jinfang Li, Yong Li, Dalin Yue, Jianyun Zhao, Haili Zhu, Yabin Liu, Wenting Chen, Xiasong Hu · 发表于：CATENA · 年份：2025 · DOI：10.1016/j.catena.2025.109158 · 被引用次数：5 · 研究领域：Soil erosion and sediment transport、Aeolian processes and effects、Coastal wetland ecosystem dynamics

The mound-building behavior of plateau pika is one of the important factors leading to meadow degradation and soil erosion in the Yellow River source area of Western China, but little is known about the influencing mechanism of microtopography on erosion hydrodynamic characteristics of bare slopes of pika mounds. In this study, we analyzed microtopography and erosion hydrodynamic characteristics on bare slopes of pika mounds under subrainfall conditions through simulation of rainfall events at six intensities (all lasting 60 min), and revealed the influencing mechanism of slope microtopographic changes on erosion hydrodynamics by using redundancy analysis (RDA) and structural equation modeling (SEM). The results showed that the maximum average erosion depth was 4.159 cm, and the maximum erosion areas accounted for 93.40 % of the total area of runoff plots; intense erosion took place mainly in the upper half of the pika mounds, while deposition was mainly limited to the lower half of the pika mounds. Surface flow velocity, flow regime parameters, and erosion power parameters all showed an increasing trend with rainfall intensity (P < 0.05), while the resistance parameters showed a decreasing trend with rainfall intensity (P < 0.05); all slope flows were laminar ( Re < 500), but transitioned from slow flows to rapid flows at a higher rainfall intensity. The RDA results showed that surface cutting degree was the key factor influencing surface runoff volume and sediment yield and...