中文摘要：

通过野外调查,研究古尔班通古特沙漠半固定沙丘植物群落的物种组成,采用株高、冠幅、体积大小级代替年龄结构,分析了典型灌木种群的生长状态及发展趋势.结果表明：在古尔班通古特沙漠半固定沙丘共调查到23种植物,出现最多的是藜科,6属8种,其次是菊科,5属6种,该沙漠植被组成数目少,群落结构简单.白梭梭主要分布在丘顶,为稳定增长型种群,而梭梭数量少.油蒿是当地工程建设后进行植被恢复而引入的物种,主要分布在迎风坡和丘顶,为增长型年龄结构,有很大的增长潜力,已经影响到原有的物种组成.白皮沙拐枣和蛇麻黄幼苗缺失,幼龄个体少,形成衰退型年龄结构,且白皮沙拐枣的空间分布区域与油蒿重合,未来可能被油蒿替代.

英文摘要：

The objective of this study was to investigate species composition,and predict future development of dominant species on semi-fixed sand dunes in the Gurbantongut Desert.Using the plant height,crown area and volume instead of age structure,the growth and development condition of dominant shrub populations were analyzed.The results showed that totally 23 species were observed,of which Chenopodiaceae occurred the most with 6 genera 8 species,followed by Asteraceae with 5 genera 6 species.The vegetation community of Gurbantunggut Desert was characterized by few species,and simple structure.As a dominant species,Haloxylon persicum was distributed mainly on the top of the dunes and was a stable increasing population.However,the number of H.ammodendron was small.Artemisia ordosica,as an exotic species introduced by vegetation restoration after construction,covered mainly in the windward and the top of dunes.The po-pulation of A.ordosica had an increasing age structure with a strongly increasing potential,which has affected local species composition.The populations of Calligonum leucocladum and Ephedra distachya were lack of seedlings and had few saplings,resulting in the declining age structure.Due to the same distribution habitat,C.leucocladum might be replaced by A.ordosica in the future.