临泽荒漠绿洲湿地植物生态系列及其物种多样性研究

The Ecological Series and Species Diversity of Plants in Wetlands in Desert Oasis in Linze

在对黑河中游临泽县荒漠绿洲湿地植物群落组成野外调查的基础上,采用TWINSPAN数量分类方法和多变量排序等方法,研究典型内陆盐沼植被类型及空间分布特征,分析了物种多样性特征,探讨了影响临泽荒漠绿洲湿地植物群落分布的主要环境因子。结果表明,在临泽荒漠绿洲湿地,共监测到40种高等植物,隶属于18科38属;湿地植被分为3个植被类型,11个群丛。在湿生带、湿生—旱生交错带和旱生带的梯度上,植被类型从以小粒苔草(Carex karoi)、小花灯芯草(Juncus articulatus)和芦苇(Phragmites australis)为主的盐碱化沼泽植被,经以赖草(Leymus secalinus)、碱蓬(Suaeda glauca)和小花棘豆(Oxytropis glabra)为主的盐化草甸植被,过渡到以苦豆子(Sophora alopecuroides)为主的碱化草原植被。物种丰富度指数、多样性指数和均匀度指数都表现为湿生—旱生交错带最高、旱生带最低的特征,而群落优势度指数表现为交错带最低、旱生带最高的特征。湿生—旱生交错带基本包括了湿生带和旱生带的优势种,其物种丰富度指数最大(21种),而旱生带最小(8种)。土壤含水量、土壤养分含量和全盐含量均是影响植被分布的主要环境因子。其中土壤含水量和全盐含量的贡献率最大,是影响临泽荒漠绿洲湿地植物群落演替的关键因子。土壤表层含水量和全盐含量也是影响物种丰富度的关键因子。此外,土壤含水量还是影响群落优势度的主要因素,而土壤全氮含量是影响群落均匀度的重要因子。

The wetlands in desert oasis play an important role in the development of the oasis and the biodiversity in arid region. Based on the field investigation of community composition in the wetlands in desert oasis, the type of plant communities, the spatial distribution characteristics and its influence factors, as well as the characteristics of species diversity were analyzed in the middle reaches of the Heihe River using the two-way indicative species analysis （TWlNSPAN） and detrended correspondence analysis （DCA）. The results showed that 40 higher plant species were observed, which are affiliated with 18 families and 38 genuses in the wetlands in desert oasis in Linze, Gansu province. The vegetation was classified into 3 types and 11 associations. The first vegetation type was halophytic marsh vegetation, which mainly consisted of halophyte and hygric species and its representative association was Carex karoi, Juncus articulatus, and Phragmites australis. The second type was salty meadow vegetation, which mainly contained mesophytic species and its representative association was Leyrnus secalinus, Suaeda glauca, and Oxytropis glabra. The third vegetation type was grass- land vegetation, which mainly contained mesophytes and xerophytes and its representative association was So- phora alopecuroides. Species richness index in the ecotone was the biggest and was the smallest in the xero- phytic plant zone. Species diversity index and evenness index had the same trends as the richness index. How- ever, the simpson index showed the opposite trends. The soil environment factors showed that the soil water content, nutrition content and total salt content were the main impact factors on the plant species distribution pattern. There were the biggest contributions in the soil water content and total salt content, which were the key factors on the succession of plant communities in the wetlands. Besides, the soil surface water content and total salt content were also the main environment factors influencing the species richness. The soil water content was the key factors on the community dominance, and the total nitrogen content was the important factors on the community evenness.