Effectiveness of vegetation cover pattern on regulating soil erosion and runoff generation in red soil environment, southern China

Coupling vegetation cover pattern with soil erosion and runoff generation positions a multi-discipline hotspot. Due to the widely occurred patchy vegetation cover and water-limited environment, regulation of vegetation cover pattern on runoff and soil erosion in arid and semiarid environment was addressed widely. In tropical and subtropical environment, patchy vegetation cover pattern also widely occurred in human-dominated landscapes. However, the effect of vegetation cover pattern on runoff generation and sediment yield and its dependence on rainfall characteristics attract little attention, and are unclear. Correspondingly, this study addresses two relevant issues: (1) the rainfall-dependent capacity of vegetation cover pattern to mitigate runoff and soil erosion; (2) rainfall-runoff and rainfall-erosion regimes mitigated by vegetation cover pattern. Eighteen 10 m-by-5 m plots were constructed for the three-year (2015–2017) observation in a humid and red-soil-covered environment in southern China. The results show that vegetation cover pattern affected the response of runoff generation and soil erosion to rainfall. The soil loss was more readily to be regulated by the fraction and spatial pattern of vegetation cover than runoff; the potential of the fraction of vegetation cover in regulating soil loss positively response to rainfall depth and rainfall intensity; and rising rainfall depth led to a weakened relationship between vegetation coverage and runoff volume. Our results illustrated that the increased rainfall intensity promotes the regression relationship between vegetation coverage and runoff volume. In this humid environment, vegetation cover pattern regulates the response of runoff and sediment discharge to rainfall characteristics; and the effectiveness of vegetation cover pattern on regulation runoff and sediment discharge was rainfall-dependent. This study indicates that including connectivity parameters in quantifying the spatial pattern of vegetation may lead to different understanding of the effectiveness of vegetation cover on hydrology and soil erosion.