Abstract: In order to reveal the effects of enclosure and grazing on plant communities in the desert steppe and find the way of conservation and utilization of desert steppe,three pairs of enclosed grasslands and grazing grasslands were selected in the desert steppe of Yanchi County,Ningxia,to investigate the planting community. The selected area was the sierozem soil and aeolian sandy soil land with the same topography,soil and vegetation conditions. Based on the sample survey,the diversity characteristics of the plant community were analyzed using the diversity index. The results showed that at the species level,the perennial grasses were mainly dominated on the sierozem soil,and the annuals and biennials were the dominant community on the aeolian sandy soil. The species composition in the enclosed grassland tended to be stable,while the grazing grassland community was still in the early stage of unstable succession. Fence enclosure was conducive to improving the biomass,height and coverage of plant communities in desert steppe;the growth of plants on sierozem soil was significantly higher than that on aeolian sandy soil. In the desert steppe with relatively few plant species,the grazing prohibition changed the species structure of community,but it did not significantly increase the diversity;it was beneficial to improve the species diversity on the aeolian sandy soil. Compared to grazing treatment,enclosure was more conducive to maintaining the stability of the ecosystem in the region.

Key words: Enclosure, Grazing, Plant community characteristics, Desert steppe

摘要： 为揭示围栏封育和围栏放牧对荒漠草原植物群落的影响，寻找荒漠草原保护与利用相结合的出路，本试验在宁夏盐池县荒漠草原选取3对封育围栏与放牧围栏，对封育围栏和相邻放牧围栏的本底条件一致的灰钙土和风沙土样带采用样线法开展植物群落样方调查，运用多样性指数等对植物群落多样性特征进行分析。结果表明，在物种水平上，灰钙土上以多年生禾本科植物为主，风沙土上以一、二年生菊科为优势群落。封育围栏群落物种组成趋于稳定状态，而放牧围栏群落还处于不稳定的演替初期。围栏封育有利于提高荒漠草原植物群落的生物量、高度和盖度；灰钙土上植物的生长量显著高于风沙土。在植物物种相对较少的荒漠草原，封育禁牧能改变群落的物种结构，但不能显著增加多样性；有利于提高风沙土上的物种多样性。相对于围栏放牧，围栏封育更有利于维持该地区生态系统的稳定。

关键词: 围栏封育, 围栏放牧, 植物群落特征, 荒漠草原