亚高山30a人工针叶林物种多样性的定量分析

QUANTITATIVE ANALYSIS OF SPECIES DIVERSITY AND SOIL FACTORS IN 30 a SUBALPINE CONIFEROUS PLANTATIONS AT DIFFERENT ALTITUDES

探讨了川西地区不同海拔梯度上 ,30a亚高山人工针叶林乔、灌、草各层物种多样性的变化规律 ;并运用逐步多元回归分析方法 ,分析了不同立地条件下土壤因子与针叶林群落乔、灌、草各层物种多样性指数之间的关系 .结果显示 :30a人工针叶林灌木层和草本层多样性指数明显高于乔木层 ;随着海拔的升高 ,灌木层和草本层物种的多样性指数逐渐降低 ,在halt2 70 0m处多样性最丰富 ,乔木物种多样性则呈现为“低→高→低”的变化趋势 ,符合“中间高度膨胀 (mid altitudebulge)”模式 ;土壤因子对 30a人工恢复针叶林多样性的影响主要是体现在灌木层和草本层的变化 ,而对乔木层物种多样性的影响不明显 ;土层厚度、土壤容重、石砾含量、枯枝落叶的贮量、CaO含量以及有机质的C N比值等土壤因子与灌木层和草本层物种多样性之间存在线性相关关系 ,分层建立了物种数、Simpson指数、Shannon Wiener指数、Menhinick指数以及Brillouin指数与相关土壤因子的回归模型 .图 2表 3参

The changing patterns of species diversity of trees, shrubs and herbs in 30 a subalpine coniferous plantations at different altitudes in northwestern Sichuan were discussed, the soil factors under different site conditions were analyzed, and the correlative diversity indices of trees, shrubs and herbs were studied using multiple regression analysis. The result showed that species diversity of shrubs and herbs was obviously more abundant than that of trees. For the changing patterns of species diversity along altitude gradients, diversity indices of shrubs and herbs gradually decreased along with elevation rising from 2 700 m, while those of trees showed a change tendency of 'lowhighlow', which fit the 'mid altitude bulge model'. Soil factors obviously affected species diversity of shrubs and herbs, but had little effect on that of trees. Linear correlation was found between species diversity of shrubs and herbs and soil factors including soil depth, Volume weight, rock contents, litters volume, CaO contents and C/N ratio in organic matters. Accordingly, regression models of species number, Simpson index, Shannon Wiener index, Menhinick index and Brillouin index of shrubs and herbs with related soil factors were establisked in this study. Fig 2, Tab 3, Ref 18