Effects of enclosure on the community characteristics of stipa bungeana grassland in Yunwu mountain

صينى. 以云雾山封育与未封区为对象，采用样线法进行调查，重点分析二者群落特征和地上生物量的变化，以期为退化草地植被恢复提供依据。结果表明：封育后本氏针茅（Stipa bungeana）群落发生较大变化，物种数显著增加、演替差异明显，由未封区的本氏针茅＋大针茅（S. gigantea）群落演替为封育后的大针茅＋本氏针茅群落；未封区本氏针茅种群的优势地位明显加强，重要值明显大于封育区；封育与未封区群落的相似性系数为0.419；物种丰富度指数和多样性指数（修正的Simpson指数、Shannon-winner指数、Audair和Groff指数）均表现为封育区〉未封区，而均匀度指数则相反；封育区地上生物量明显增加，其中禾本科、蔷薇科和杂类草占总生物量的比例均表现为封育〉未封区，而菊科则相反。

إنجليزي. The Stipa bungeana Trin. , a good forage grass, is an important grassland community type distributed broadly in large areas in Yunwu Mountain Nature Reserve. The characteristics and aboveground biomass of S. bungeana community were analyzed based on the plot data for the enclosure vs. non-enclosure areas. The results were as following： Longtime enclosure resulted in the changes of plant community with increase in species and significant succession. The community component in the non-enclosure area was S. bungeana＋S, gigantea while S. gigantea＋S, bungeana in the enclosure area. The dominance status of S. bungeana was enhanced in the non-enclosure area with significantly higher community important value in comparison with the enclosure area. Similarity index between the enclosed and non-enclosed S. bungeana communities reached to 0. 419. The richness index and the three species diversity indices （Simpson index, Shannon-winner index, Audair and Groff index） of S. bungeana community in enclosure area were higher than those in non-enclosure area, while the evenness was reversed. The total aboveground biomass and the biomass percentages of Gramineae, Rosaceae, and fobs in enclosure area were higher than those in non-enclosure area but opposite in the biomass percentage of compositae.