温性荒漠草原开垦弃耕后不同年限群落植物特征变化

Changes of Plant Characteristics in Different Years after Abandoned Cultivation in Temperate Desert Steppe

通过对弃耕10年、 20年、 30年三个不同年限草地群落组分及物种多样性进行研究,结果表明:随弃耕年限的延长,一年生植物减少,根系发达、适应性强的多年生植物明显增加,并且逐渐成为草地植物群落的优势种;在此过程中,禾本科植物的数量和种类也在逐渐增加,说明弃耕30年的草地植被仍然处在激烈的演替过程中,没有达到群落结构的稳定状态;物种多样性指数和均匀度指数随弃耕年限的延长先增大后减小,且弃耕前期(10a与20a之间)变化小于后期(20a与30a之间);丰富度随弃耕年限的增加而减小,且差异显著(P <0.05),说明弃耕时间越长,越不利于植物多样性的保护。

In this paper,the community composition and species diversity of grassland abandoned for 10 years,20 years and 30 years were studied.The results showed the annual plants decreased with the extension of abandoned years,the number and species of gramineae increased in the course of the development of roots and adaptability of the perennial plant,which gradually became the dominant species of the grassland plant community,the grassland vegetation after 30 years of abandoned cultivation was still in the process of drastic succession and did not reach the stable state of community structure.The species diversity index and evenness index increased firstly and then decreased with the extension of abandoned cultivation years,and the change of the early abandoned tillage(between 10a and 20a)was less than that of the late abandoned tillage(between 20a and 30a),the richness decreased with the increase of the abandoned tillage years,and the difference was significant(P<0.05).The longer the abandoned tillage time was,the worse the protection of plant diversity was.