甘肃河西戈壁植物群落组成特征及其多样性研究

Study on composition and diversity of phytocoenosium in Gobi region of Hexi,Gansu

采用"样带+样方"方法,以河西戈壁典型区域64个样地上的576个样方植被为研究对象,分析研究了河西戈壁植物群落组成特征、生活型谱以及物种多样性等。结果表明,研究区共出现81种植物,分属于21科60属,其主要分属在藜科、菊科、禾本科、蒺藜科及豆科中(属、种百分比和均在55%以上),其余16个科植物几乎为2属2种或单属单种。草本层优势种植物为短命避旱的1年生草本-盐生草、画眉草、五星蒿、小车前、蝎虎驼蹄瓣,灌木层优势种为超旱生植物红砂、合头草、泡泡刺、中亚紫菀木、膜果麻黄,乔木层植物仅有胡杨1种。植物群落几乎由灌木和草本组成,群落生活型谱以地面芽植物和1年生草本为主。该区域整个植物群落呈现出物种丰富度指数和多样性指数相对较大,均匀度指数Jsw值、物种总数N均较小。

Investigation on vegetation of 576 quadrates distributing in 64 sample plots of typical Gobi region in the northwest of Gansu has been conducted by line transect and quadrate methods,and the composition characteristic,life form spectrum and species diversity of phytocoenosium was analyzed and researched. The results show that there are 81 species in total,belonging to 60 genera and 21 families,which mainly are distributed in Chenopodiaceae,Asteraceae,Poaceae,Zygophyllaceae and Fabaceae（ both percentages of genera and family are55% above）. And the composition of whole phytocoenosium shows that most species belong to the minority of families and a few species belong to the majority of families obviously. The dominant species of herb layer are composed of ephemeral and avoiding dry plants,such as Halogeton glomeratus,Eragrostis pilosa, Bassia dasyphylla,Plantago minuta,Zygophyllum mucronatum and so on. The dominant species of shrub layer are Reaumuria soongarica,Sympegma regelii,Nitraria sphaerocarpa,Asterothamnus centraliasiaticus and Ephedra.The plant community is composed of shrub and the herb nearly,and life form spectrum of phytocoenosium is mainly composed of hemicryptophytes and therophytes whose percentages of species are 43. 11% and 23. 46% in turn. The indices of richness and diversity of species are relatively large,and the Jsw value of species evenness index and total number of species is relatively small. it means that species distribution of plant growing in this place is extremely uneven,and vegetation stability is low.