石羊河下游盐碱化退耕地植被自然演替特征研究

Study on Characteristics of Succession of Vegetation in Salinized Abandoned-fields in the Lower Reaches of Shiyang River

采用时空互代的方法,对石羊河下游盐碱化退耕地21个样地63个样方的自然恢复植被进行调查,并对各植被群落特征进行了分析。结果表明:退耕后50年的植被演替过程中,调查样方内共出现植物22种,分属于11科21属;退耕地植被自然恢复的过程大致经历了田旋花、独行菜、骆驼蒿、苏枸杞和盐爪爪5种群落类型的演替;在整个演替过程中,植被恢复大体分为迅速恢复期(1～2年)、初始更替期(3～8年)、高级更替期(9～28年)和缓慢恢复期(29年以后)4个阶段,同时,Margalef指数、Simpon指数和Shannon-wiener指数均呈现出波动式减小的变化趋势,Monk指数、Pielou指数和Alatalo指数则呈现出波动式增大的变化趋势。

The natural rehabilitation of vegetation of 21 samples,63 quadrats from salinized abandoned-fields in Minqin oasis was studied by means of the method of spatio-temporal inter-substitution.The results showed that 22 species in 21 genera and 11 families had been found in the 50 years natural succession of vegetation after the fields abandoned.The succession of the vegetation in abandoned-fields mainly experienced five types of community were Convolvulus arvensis,Lepidium apetalum,Peganum harmala,Lycium ruthenicum and Kalidium foliatum community.In the whole course of succession,the natural restoration of vegetation in abandoned-fields can be divided into four stages as follows,the speedy restoration stage（1～2 years）,primary subrogation stage（3～8 years）,high-level subrogation stage（9～28 years） and slow restoration stage（after 29 years）,and the change of Margale index,Simpon index and Shannon-wiener index is decreasing fluctuatly,the indices of Monk,Pielou and Alatalo are increasing fluctuatly.