生物多样性与地形及土壤因素对坡面产流产沙的耦合影响

生物多样性关系到生态系统的功能，而坡度和土壤因素是影响坡面产流产沙的重要因子。本研究基于黄土丘陵区生物多样性，并引入坡度、降雨前土壤含水量和土壤容重，探究其与坡面产流产沙总量的耦合关系。通过野外人工降雨试验，记录草本、灌木和乔木群落下的产流时间和产流产沙总量，并开展土壤植被调查。结果表明，与草本和乔木群落相比，灌木群落在延长产流开始时间和降低产沙总量上表现更优；植被群落功能离散度指数(FDiv)对产沙总量影响最大，Simpson指数(D)对产流总量影响最大，坡度仍然是不可忽视的第二重要影响因素；产流总量与坡度、土壤容重、D和功能丰富度指数(FRic)的回归关系优于产流总量分别与其的回归关系；产沙总量与坡度和FDiv指数的回归关系优于产沙总量分别与其的回归关系。植被保护与坡度改善将是该区水土保持规划工作的重点。

Coupling Effects of Biodiversity with Topographic and Soil Factors on Slope Runoff-Sediment Yield

Biodiversity is related to the function of ecosystem,while slope and soil factors are the main factors influencing runoff-sediment yield. This study is based on biodiversity in Hilly area of Loess Plateau,and coupled with runoff and sediment yield by introducing three indicators:slope,soil water content before rainfall and soil bulk density before rainfall. Through artificial simulated rainfall tests in the field,the runoff start time and the runoff-sediment yield under three vegetation communities of the herbaceous communities,shrub communities and forest communities were recorded along with soil and vegetation surveys. The survey results show that compared with herbaceous communities and forest communities,shrub communities performed better in extending the runoff start time and reducing the total sediment yield. The functional dispersion index (FDiv) of vegetation community has the greatest influence on total sediment yield,the Simpson index (D) has the greatest influence on total runoff yield,and slope is still the second most important influencing factor that cannot be ignored. The regression relationship between the total runoff yield and slope,soil bulk density,D and functional richness index (FRic) was superior to that of relationships built using the above-mentioned parameters singly. The regression relationship between total sediment yield and slope and FDiv index was superior to that of relationships built using the above-mentioned parameters singly. Vegetation protection and slope improvement should beset as the focus of water and soil conservation planning in this area.