Abstract: The changes of plant diversity of Leymus chinensis grassland were studied along the gradi-ent of soil salinization in the Songnen Plain of China by use of 8 diversity indice from 3 measurements,richness, evenness and diversrty and Zahl’s Jack-knifing statishc method.The results showed:With aggravating soil salinizaion, the plant diversity of community decreased monotonously and was related to the pH and conductivity of soil positively, and negaively to soil Waer in the form of expoment.The series of plant diversity was Leymus chinensis-herbage community > L.chinensis community > L.chinensis-Puccinellia tenuiflora community > P.tenuiflora community> P.chinampoensis community> Suaeda corniculata community, and was consistent with the series of soil salinization.The changes of plant abundance distributions and the loss of moderate abundance species better accounted for the effect of soil salinization on the plant diversity of L.chinensis grassland.The changes of life-form diversity tended towards short cyclogeny species gaining the upper hand.

Key words: Leymus chinensis grassland, Soil salinization, Plant diversity, Plant abundance distribution, Life-form diversity

摘要： 从群落物种丰富度、均匀度和多样性三个测度水平,采用八个指数和Zahl的大折刀法统计处理,探讨了松嫩平原单草草地次生盐碱化梯度植物多样性的变化,结果表明,随着土壤盐碱化的加重,群落植物多样性单调衰减,并与土壤pH值和电导率呈显著指数负相关,与土壤水分是指数正相关;其植物多样性的演替序列是:羊草一条类草群落＞羊草群落＞羊草-星星草群落＞星星草群落＞朝鲜碱茅群落＞角碱蓬群落,结果与次生盐碱化演替序列一致;其植物多度分布格局的变化随着土壤盐碱化的加重导致个体数量居中种类的缺失,该结果较好地解释了土壤盐碱化对羊草草地植物多样性的影响;其生活型多样性的变化主要表现在:活土壤盐碱化逆行演替梯度,地面植物多样性相对减少,一年生植物多样性相对增加,趋向于短生活周期物种占优势。

关键词: 羊草草地, 土壤盐碱化, 植物多样性, 植物多度分布, 生活型多样性