Regulation of alpine meadow patch coverage on runoff and sediment under natural rainfall on the eastern Qinghai-Tibetan Plateau

Soil and water conservation is the most important among ecological functions of alpine meadow on the Qinghai-Tibetan Plateau. Quantitative assessment of the effects of meadow patch coverage (MPC) on the runoff and sediment processes in alpine meadow is urgent for predicting the water conservation function of this special alpine ecosystem. Here, a field experiment was conducted to determine the effects of different meadow patch coverage through runoff and sediment processes in a typical alpine meadow on the eastern Qinghai-Tibetan Plateau. The results showed that runoff in 30% and 60% MPC plots were 39.4% and 37.9% less than in 90% MPC plot, respectively. The sediment yield in 60% and 90% MPC plots were 77.9% and 82.1% less than in 30% MPC plot, respectively. The sediment concentration in 30% MPC in heavy rainfall scenario is 4.34 times and 6.51 times higher than that in light rainfall scenario and moderate rainfall scenario, respectively. Our results indicated that MPC presented a greater impact on sediment yield than runoff volume, although runoff was greatly affected by rainfall. The higher MPC followed the greater runoff coefficient and the lower sediment concentration. The influences of MPC on runoff and sediment yield in light rainfall scenario and moderate rainfall scenario were weaker than those in heavy rainfall scenario. It is necessary to maintain surface runoff while controlling soil loss for realizing the sustainability of alpine meadow ecosystems. Therefore, these findings may conducive to offer a theoretical guidance to achieve the combined goal of soil erosion regulation during alpine meadow degradation on the Qinghai-Tibetan Plateau.