草甸草原撂荒地演替过程中植被多样性指数变化

摘要

In different years of abandoned grassland land of state-owned farm (abandoned years:2 years,4 years,10 years,23 years natural grass CK)in meadow steppe of Inner Mongolia as the research object,vegetation diversity characteristics was systematicallystudied to analyze and discuss the relationship of the abandoned years and succession processand different diversity index variation,in order to provide theoretical basis for the scientific evaluation of succession process of returning cultivated land to grassland and the development of reasonable vegetation restoration measures.The results showed that the communi-ty structure and appearance were different significantly with the different abandoned time,the perennial plants were increased with the increase of abandoned time.The Shannon-Wiener diversity index reached 1. 81in abandoned 23 years land,which was significantly higher than other sample plots(P<0.05).Simpson diversity index had similar variation pattern,but other diversity indexeswere not the same.Beta diversity index decreased with the increase of abandoned time,and the longer abandoned time was,the higher the similarity coefficient with the natural grassland was.The similarity coefficient between abandoned 23 years plot and natural grasslandreached 5 1.88.The results indicated that the community structure had a com-plex trend with the increase of abandoned time.%以内蒙古草甸草原区国有农牧场不同年限草原撂荒地(2年、4年、10年、23年和天然草 CK)为研究对象,系统研究不同年限撂荒地植被多样性变化特征,分析并探讨撂荒年限和演替进程的关系及不同多样性指数变化规律,为科学评估退耕还草的进程以及制定合理植被恢复措施提供理论依据。结果表明：不同撂荒年限的样地群落结构和外貌特征显著不同,多年生植物的种类和数量随撂荒年限的增加而逐渐增加；撂荒23年的 Shannon-Wiener 多样性指数达到1.81,显著高于其他撂荒年限样地(P<0.05),Simpson 多样性指数有类似的变化规律,但其他多样性指数并未体现随撂荒年限增加而线性增加的规律；β多样性指数随撂荒年限的增大而减小,撂荒时间越长,与天然草地相似性系数越高,撂荒23年样地与天然草地相似性系数达到51.88；撂荒年限的增加使草甸草原撂荒地群落结构趋于复杂化。