石羊河下游盐渍化弃耕地植被演替特征分析

Characteristics of Vegetation Succession on Salinized Abandoned Fields in Lower Reaches of Shiyang River

以石羊河下游不同年代盐渍化弃耕地自然群落为对象,利用重要值、物种多样性理论研究植被演替的特征。结果显示,石羊河下游盐渍化弃耕地植被演替一般经历一年生田间杂草、多年生荒漠草本和荒漠灌木三个阶段。群落演替规律:藜(Chenopodiumalbum)+田旋花(Convolvulus arvensis)群落(1～2年)→骆驼蒿(Peganumnigellastrum)+骆驼蓬(Peganumharmala)群落(3～10年)→苏枸杞(Lycium ruthenicum)+黄毛头(Kalidium cuspidatum var.sinicum)群落(10～40年)→黄毛头群落(顶级群落)。研究表明,随着群落演替时间的增加,物种丰富度呈下降趋势,而物种多样性呈先下降后上升,最后略有下降并趋于稳定,群落结构趋于简单。

The studies which provided the important basis for vegetation management,transformation and rehabilitation on vegetation especially process and mechanism of natural rehabilitation and vegetation reconstruction in destroyed ecosystems had important significance in theory and in practice.The paper had studied the natural communities of salinized abandoned fields with different durations in lower reaches of Shiyang River with the theory of important value and species diversity.The results showed that vegetation succession on salinized abandoned fields in lower reaches of Shiyang River had three phases：the field annual weeds,the desert perennial herbage and the desert brush.The communities succession had four phases：the community Chenopodium album＋Convolvulus arvensis（1～2 years）→the community Peganum nigellastrum＋Peganum harmala（3～10years）→the community Lycium ruthenicum＋Kalidium cuspidatum var.sinicum（10～40 years）→the community Kalidium cuspidatum var.sinicum（top community）.With the increasing of succession process,the species richness was decreasing,species diversity was changing with firstly decreasing,secondly increasing and lastly decreasing slightly and tended to stability and the community structure was tended to simplify.