Short-term changes in slope vegetation patch patterns and their regulation on sediment connectivity in an arid area

Vegetation patch patterns play a critical role in regulating surface hydrological processes in arid ecosystems. However, the short-term changes in these patterns and their coupling mechanisms with slope sediment connectivity (IC) remain poorly understood. In this study, we combined three years of in situ observations with Unmanned Aerial Vehicle (UAV) and Terrestrial Laser Scanning (TLS) technologies to investigate the short-term dynamics of three vegetation patterns (random, uniform, and aggregated) and their impacts on soil erosion. The results showed that vegetation patch patterns exhibited signs of short-term degradation under erosive disturbance, characterized by increasingly complex patch boundaries, heightened fragmentation, and reduced functional connectivity. Specifically, the random pattern exhibited the most severe fragmentation, with the Landscape Shape Index (LSI) increasing by 27.76%. In terms of erosion regulation, the uniform pattern demonstrated the strongest runoff and sediment interception capacity, reducing runoff and sediment yield by 40.46% and 53.48%, respectively, compared with bare slopes. Furthermore, landscape metric analysis indicated that both LSI and COHESION were generally negatively associated with sediment connectivity (IC). The pattern-based prediction equations further showed that IC promoted runoff and sediment export, whereas CONNECT reduced erosion by interrupting continuous transport pathways. Collectively, our findings suggest that future ecological restoration management in arid regions should move beyond increasing vegetation coverage alone and optimize vegetation spatial configuration according to site water availability, vegetation stability, and the distribution of IC hotspots. Where site conditions permit, relatively uniform vegetation patterns may be considered to enhance runoff interception and sediment retention. Targeted interventions in high-IC areas may further help disrupt sediment connectivity, reduce runoff-driven sediment transport, and mitigate erosion risk.