围栏封育对西藏退化高寒草甸物种多样性及生产力的影响

Effect of Enclosure on Species Diversity and Productivity of Degraded Alpine Meadow in Tibet

为了解围栏封育对草甸群落的影响,为西藏地区的草甸管理和土地荒漠化治理提供基础数据及理论指导,以西藏林周县退化高寒草甸植物群落为研究对象,对比分析围栏封育20年的草甸群落与自由放牧草甸群落的组成、重要值、生物量及其生物多样性差异。结果表明:经20年封育的草甸植物群落特征较自由放牧区发生显著变化,其物种组成增加7种,优势种发生了改变,群落的盖度、高度、生物量分别增加38.56%、354.02%和191.67%,丰富度指数、Shannon-Wiener指数、Simpson指数、Pielou指数分别增加35.00%、2.61%、11.11%和-7.78%。结论:西藏高原草地生态系统十分脆弱,但在过度放牧干扰下严重退化的草地通过合理的利用方式,可以恢复到健康状态。

The composition, important value, biomass and biodiversity of enclosure meadow phytoecommunity above 20 years and free choice grazing phytoecommunity in Linzhou County, Tibet were compared and analyzed to know the effect of enclosure on meadow communities and to provide the basic data and theoretical guidance for meadow management and land rocky desertification control in Tibet. Results： The characteristics of the enclosure meadow phytoecommunity above 20 years changes significantly compared with the free choice grazing phytoecommunity and its species composition increases by 7 species. The dominant species are changed. The coverage, height and biomass of the community increase by 38.56%, 354. 02% and 191.67% respectively. The richness, Shannon-Wiener. Simpson and Pielou index increases by 35.00 %, 2.61%, 11.11% and--7.78 % separately. In conclusion, the grassland ecosystem of Tibet Plateau is very weak but the healthy status of the serious degradation grassland under overgrazing disturbance can be recovered by the rational utilization pattern.