石羊河下游不同类型荒漠草地黑果枸杞群落结构及物种多样性特征

选择石羊河下游4种不同类型荒漠草地黑果枸杞(Lycium ruthenicum)群落,采用重要值、丰富度指数、Simpson和shannon-wiener多样性指数、Pielou和Alatalo均匀度指数对不同立地类型黑果枸杞群落结构特征和物种多样性进行了分析,结果表明:植物群落组成主要集中在藜科、蒺藜科、菊科和禾本科,这4大科植物在该区具有较强的生态适应性,所调查群落中共有植物种31种,分属9科28属,单科单属种较多,占到了总科数的一半;研究区群落结构简单,物种相对单一,黑果枸杞在群落中占有重要地位,且重要值相对较大,对群落的稳定性起关键作用;植物的生活型中灌木植物占优势,其次是一年生草本植物,多年生草本植物所占的比例最少;不同类型荒漠草地中黑果枸杞群落物种多样性指数均偏低,物种丰富度较低,生态优势度较高,种间相遇率偏低,群落中物种分布不均匀,表明植被群落结构简单、组织水平低,优势种或建群种在群落中占据主导地位。

Characteristics and Species Diversity of Lycium ruthenicum on Different Types of Desert Grassland in Shiyang River

Four types of Lycium ruthenicum communities were selected from different types of grassland in the lowerreaches of Shiyang River and their characteristics and species diversity were analyzed using the index of important value,species richness Margalef index,diversity Simpson and Shannon-wiener index,Alatalo and Pielou evenness index.The results showed that Chenopodiaceae,Zygophyllaceae,Compositac and Poaceae had stronge cological adaptability and their community compositions were relatively simple.Among the investigated communities,there were 31 kinds of species belonging to 9 families and 28 genera.There were more single genus occupying 50％ of total genus;the community structure was simple and species were relatively single,and Lycium ruthenicum occupied an important position in the community with relatively bigger importantance value.It played a dominated role in the community.The community composition was relatively simple.Shrubs dominated in this area,followed by annual herbs,and perennial herb accounted for the minimum proportion in different types of desert grasslands.Lycium ruthenicum communities had low species richness,low inter-specific encounter rate,high ecological dominance,and uneven distribution of species.It showed that the vegetation community structure was simple,the organization level was low,and the dominant species or constructive species occupied a dominant position in the community.