贺兰山羽叶丁香分布区的植物物种多样性特性研究

Species Diversity of Syringa pinnatifolia Community in Helan Mountains

野外踏查及样地调查的结果表明，在贺兰山羽叶丁香分布区内，共有维管束植物223种，隶属于144属50科。其植物区系地理成分较复杂，包括变型一共有18个类型，以北温带成分占绝对优势。在植物的生活型谱中，地面芽植物远远多于其他类型，达108种，占48．43％。统计分析46个样地调查资料，表明羽叶丁香群落的垂直结构简单，分灌木及草本两层，其灌木层的植物种类较多，达32种，草本层很发达，有170种草本植物和7种半灌木。物种多样性测度结果表明，其植物群落的草本层的植物物种多样性最高；不同海拔高度（段）的植物物种多样性比较结果表明，海拔高度2100～2200m的植物物种多样性最高；按坡向，东北坡的植物物种多样性最高。

The floral characteristics of Syringa pinnatifolia community in Helan mountains was studied through field survey and sample plot investigation. The study results showed that there were 223 vascular species in S. pinnatifolia distribution area of Helan mountains, belonging to 50 families and 144 genera. The floral geograph- ical composition was complex, with 18 types including sub-type, and the north temperate was the dominant components. Hemicryptophytes were in majority among all the life torms and 108 species belong to Hemicryptophytes, accounting for 48.43 % of the total species number. According to the data from 46 sample plots, the vertical structure of S. pinnatifolia community was simple, the shrub layer was more complex, it had 32 species. The herbage layer was flourishing, and it had 170 species herbage and 7 specie sub-shrnb. The results of measuring species diversity showed that the species diversity and herbage layer was the highest. The results of measuring species diversity with the elevation, the species diversity was the highest in 2 100 -2 200 m. As far as the aspect was concerned, the highest species diversity was found in northeast slope.