黄土丘陵区植物群落功能多样性/物种多样性与产流产沙响应关系

Response Relationship Between Functional Diversity/Species Diversity and Rainfall-Runoff-Sediment Yield in Loess Hilly Region

为了探索合适的植被参数用于评估植被的水土保持效益,我们在安塞县纸坊沟流域,构建了植被盖度相近但结构不同的试验小区,并测量了每个小区中优势种的比叶面积、叶组织密度、比根长、根组织密度等功能性状,并根据测得的性状数据,计算了群落功能丰富度指数(FR_(ic))、群落功能均匀度指数(FE_(ve))和群落功能离散度指数(FD_(iv))3种功能多样性指数。依据样方调查结果计算了不同小区的Simpson指数、Shannon-Wiener指数、Pielou指数3物种多样性指数。并通过野外模拟降雨试验,将雨强固定在120 mm/h,降雨历时30 min。对不同小区的产流时间、产流产沙总量及其与群落多样性指数的相关关系进行了分析。结果表明:(1)结束产流时间随着群落功能丰富度指数(FR_(ic))的增大而逐渐减小;(2)在3个群落功能多样性指数中,坡面产流总量只与群落功能丰富度指数(FR_(ic))有线性的响应关系;(3)通过与Simpson指数、Shannon-Wiener指数、Pielou指数比较,群落功能丰富度指数(FR_(ic))回归结果的R^2>0.5,其他指数结果的R2均在0.01左右,功能多样性指数比物种多样性指数响应敏感,能更好地反映群落水土保持效益。

From the perspective of plant functional diversity and species diversity,an experiment was conducted to explore the appropriate vegetation parameters for assessing the soil and water conservation benefits of vegetation under the simulated rainfall.According to the design of the study,the experimental plots with similar vegetation coverage and different vegetation structure were selected in Zhifanggou Watershed,Ansai County.In the selected plots,we measured the traits of the dominant species including the specific leaf area,leaf tissue density,and specific root length and root tissue density.The functional richness index（FR（ic））,the functional evenness index（FE（ve））,the fFunctional divergence index（FR（iv））,and the species diversity index were calculated.The simulated rainfall intensity was 150 mm/h and the rainfall duration was 30 min.The runoff time,total runoff and sediment yield of each plot were recorded,and the correlation between them and the community diversity index were analyzed.The results showed that：（1）the runoff duration decreased with the increase of the FR（ic）;（2）among the three community functional diversity indexes,only the FR（ic） showed the linear response relationship to the total runoff of the slope;（3）compared with the Simpson index,Shannon-Wiener index and Pielou index,the functional diversity index is more sensitive,which can better reflect the benefits of soil and water conservation.