中文摘要：

采用路线调查法和样方法研究了陇东黄土高原丘陵沟壑区天然草地植物群落组成的特征.结果表明,该研究区地带性植被的主要类型为草甸草原和典型草原,草甸草原以蒿类、白羊草和白草为代表群落;典型草原以长芒草、蒿类、百里香和毛沙芦草等为代表群落.草地群落物种组成较为简单,优势种的优势度显著,其中长芒草、山蒿、冷蒿、牛枝子、糙隐子草、铁杆蒿、阿尔泰狗娃花、赖草、猪毛蒿、百里香等是群落物种组成中相对重要的物种;天然草地群落数量特征的平均值为：种数17.1、多度163.5、高度49.2 cm、盖度52.8%、鲜重284.9 g·m^-2、干重151.8 g·m^-2;草甸草原群落的高度、盖度、生物量和物种丰富度值均大于典型草原.

英文摘要：

Route survey and quadrat method were adopted to investigate the florae on natural grasslands in hilly and gully area of the Loess Plateau lying in east Gansu Province. The investigation showed that in the region,the zonal florae were mainly meadow grassland and typical grassland;the meadow grasslands were represented by Bothriochloa ischaemum,Penniselum flaccidum and Artemisia sp. communities and the typical grasslands were represented by Stipa bungeana ,Artemisia sp. ,Thymus mongolicus and Agropyron rnongolicum var. villosum communities. The communities of the grasslands had a simple species composition and their dominant species had a significant degree of dominance;the important ones of the dominant species were Stipa bungeana ,Artemisia brachylona ,Artemisia frigida , Lespedeza potaninii , Cleistogenes squarrosa ,Artemisia gmelinii , Heteropappus altaicus, Leymus secalinus ,Artemisia scoparia and Thymus mongolicus. The species number,ahundance,height,coverage fresh weight and dry weight of the natural grasslands,some of the quantitative eigenvalues,were separately 17. 1,163.5,49.2 cm,52.8% ,284, 9 g·m^-2 and 151.8g·m^-2 on average and the height,coverage and biomass and species abundance of the mead ow grassland were higher than those of the typical grassland.