Response relationship between vegetation structure and runoff-sediment yield in the hilly and gully area of the Loess Plateau, China

The structure of the vegetation has a significant impact on how much runoff and sediment is produced. Choosing the right parameters to evaluate the correlations between vegetation and runoff-sediment yield, however, is fraught with uncertainty. We chose 18 vegetation plots with a range of vegetation types and structural char-acteristics for this study to investigate the applicability of various vegetation structure parameters in identify in the response relationship between vegetation and runoff-sediment yield through field artificial rainfall experi-ments. The vegetation coverage, stratified vegetation cover index (Cs), species diversity and functional diversity were among the criteria of vegetation structure. The findings revealed that: (1) There was a significant difference in the runoff start time and sediment yield differed significantly between vegetation types, with shrub com-munities having a longer start time and the lowest sediment yield; (2) The vegetation coverage of the community had a significant impact on the runoff start time and, when combined with Cs, explained 48% of the runoff start time. (3) Simpson index (D) and functional richness (FRic) significantly influenced the total runoff yield and along with Cs explained 46% of the total runoff yield. Cs, coverage and FRic also positively influenced the runoff end time, with a total explanation of 29%. Functional divergence (FDiv) had a significant negative effect on the total sediment yield. Together with coverage and Cs, FDiv explained 66% of the total sediment yield. These results demonstrated how biodiversity consideration helped to clarify connections between vegetation structure and runoff-sediment yield.