藏东南小型泥石流沉积区植物群落结构和多样性研究

Study on the Diversity and Structure of Plant Community in Small Debris Flow Deposition Area in Southeastern Tibet

采用样方调查的方法对3个发生不同年限的藏东南小型泥石流沉积区植物群落结构和多样性水平进行调查分析,结果表明:①泥石流沟道沉积区植物群落分别有藏川杨+腺果大叶蔷薇+沿阶草群落、藏川杨+鸡骨柴+苔草群落和藏川杨+高丛珍珠梅+苔草群落3种类型.②发生20a的泥石流沟道沉积区植物群落物种多样性水平最高.③藏川杨+腺果大叶蔷薇+沿阶草群落中乔木层多样性指数大于草本层,其余群落均为灌木层物种多样性水平高于草本层,乔木层物种多样性水平最低.④泥石流沉积区植物群落演替过程表明杨柳科植物为先锋种组成群落贯穿于整个演替进程.

Quadrat survey was made to study the plant community structure and diversity of the debris flow deposition areas of southeastern Tibet in three different years.Three types of plant communities were shown to exist in the channel debris flow deposition area,i.e.Populus szechuanica Schneid.var.tibetica Schneid ＋ Rosa macrophylla Lindl.var.glandulifera Yü et Ku ＋ Ophiopogon bodinieri Levl,Populus szechuanica Schneid.var.tibetica Schneid ＋ Elsholtzia fruticosa（D.Don） Rehd.＋ Carex sp.and Populus pseudoglauca C.Wang et P.Y.Fu ＋ Sorbaria arborea Schneid.＋ Carex sp.The channel debris flow deposition area of 20a had the highest species diversity.The diversity index of the tree layer was greater than that of the herb layer in Populus szechuanica Schneid.var.tibetica Schneid ＋ Rosa macrophylla Lindl.var.glandulifera Yü et Ku＋ Ophiopogon bodinieri Levl communities,the diversity index of the shrub layer was greater than that of the herb layer in other communities,and it was at the lowest level of the tree layer.The plant community succession process of the debris flow deposition area showed that the Salicaceous plants as pioneer species composed a community throughout the entire succession process.