河西走廊西段戈壁灌木群落多样性及其分布格局研究

通过野外样方调查河西走廊西段荒漠戈壁典型灌木群落多样性状况，研究探讨了 8 种典型 灌木群落物种多样性的空间分布格局及其与地理因子的关系，对荒漠戈壁植物群落的多样性的保 护和可持续发展具有重要意义。结果表明：(1) 8 个典型灌木群落 Shannon-Wiener 指数、Simpson 指 数、Margalef 指数和 Pielou 指数从高到低为：盐爪爪群落>麻黄群落>合头草群落>红砂群落>梭梭群 落>泡泡刺群落>多枝柽柳群落>沙拐枣群落；波动范围分别为 0.314 ~ 1.355、0.179 ~ 0.666、0.334 ~ 1.222 和 0.051 ~ 0.218，说明荒漠戈壁灌木群落物种多样性指数偏低，群落结构简单，物种组成稀 少。(2) 不同灌木群落内物种数越多，群落间 Jaccard 相似性系数越大。大部分灌木群落类型间 Jac? card 相似性在 0.20 ~ 0.60 之间，群落间相似水平较低，群落相对稳定。(3) 随着海拔的升高，Margalef 指数、Pielou 指数和 Shannon-Wiener 指数均呈先增加后降低的单峰型分布格局，最大值出现在海拔 2 000 m，且与海拔显著相关（P<0.05）；在经度梯度上，从东到西，Margalef 指数、Pielou 指数和 Shan? non-Wiener 指数呈递增格局，但与经度无显著相关性（P>0.05）；在纬度梯度上，从南到北，Margalef 指数、Pielou 指数和 Shannon-Wiener 指数呈显著递增趋势（P<0.05）。总体上，荒漠戈壁灌木群落物 种多样性呈现出明显的垂直（海拔）和纬度地带性分布格局。

Gobi shrub species diversity and its distribution pattern in west Hexi Corridor

To elucidate the plant diversity of typical shrub communities species diversity in west of Hexi Corridor, Gansu Province, China, spatial distribution pattern of species diversity and its relationship with geographical factors were discussed in this paper via field sample survey. It is important for maintaining, self-improvement, scientific conservation, and managing the diversity of the gobi shrub communities. Results showed that: (1) Simpson index, Shannon-Wiener index, richness Margalef index, and evenness Pielou index of eight desert gobi shrub communities are calculated and compared. The order is Kalidium foliatum community>Ephedra przewalskii community> Sympegma regelii community>Reaumuria songarica community>Haloxylon ammodendron community>Nitraria sphaerocarpa community> Tamarix ramosissima community>Calligonum mongolicum community. The Shannon-Wiener, Simpson, Margalef, and Pielou fluctuation range of the indexes were 0.314-1.355, 0.179-0.666, 0.334-1.222, and 0.051-0.218. The species diversity indexes of gobi desert shrub communities were observed to be low. The structure and composition of the shrub communities were simple and rare. (2) More species in the community results in higher Jaccard similarity coefficient between communities. The Jaccard similarity between most shrub community types ranges from 0.20 to 0.60. Most Jaccard similarity levels between communities were low and the communities were relatively stable. (3) For the species diversity such as Margalef and Pielou, the Shannon-Wiener index showed an increasing and then decreasing trend, similar to the Unimodal pattern, where the maximum occurred at 2000 m of the elevational gradient. The correlation between species diversity and altitude were significant (P<0.05). The species density had a significant increasing trend from south to north (P<0.05), while it had a non-significant increasing trend from east to west (P>0.05). On the community scale, the species diversity of gobi desert shrub communities showed obvious vertical (altitude) and latitude zonal distribution pattern.