Abstract: A five-successive-year fencing of the lightly and heavily grazing Potentilla fruticosa shrublands has decreased their species richness, plant diversity and evenness. The total coverage,dead materials coverage,and height of top and bottom layers of the plant communities have all increased, while the live shoot coverage has decreased. Fencing has also affected the characteristics of the two plots’ plant pupulations. In the lightly grazing plot, the above-ground biomass of sedges,forbs,and P.fruticosa have dwindled,whereas the biomass of dead materials and grasses have expanded,with the biomass of dead materials increasing markedly(P<0.05).The proportion of palatable herbages dropped from 0.72 to 0.62. In the heavily grazing plot,the biomass of dead materials,grasses and sedges have increased noticeably(P<0.05),the biomass of P.fruticosa did not expanded much(P>0.05),while that of forbs dwindled markedly(P<0.05).The proportion of palatable herbages rose from 0.48 to 0.59.Consequently,fencing impairs the quality of lightly grazing P.fruticosa shrubland,and improves the quality of heavily grazing P.fruticosa shrubland.

Key words: Grassland science, Ecology, Fencing, Lightly grazing, Heavily grazing, Potentilla fruticosa shrub

摘要： 连续5年的封育对轻牧与重牧区金露梅灌丛产生了影响。结果表明:封育后轻牧与重牧区的丰富度指数、多样性指数和均匀度指数都有所下降;总盖度、枯草盖度和上下层株高增加,绿草盖度减少,群落内主要植物种群特征发生相应变化,轻牧区金露梅灌丛的莎草类、杂草类和金露梅的地上生物量减少,而枯草、禾草的生物量增加,其中枯草生物量增加显著(P<0.05),优良牧草比例由0.72下降为0.62;在重牧区金露梅灌丛的枯草、禾草及莎草生物量增加显著(P<0.05),金露梅的生物量增加不显著(P>0.05),而杂草生物量减少显著(P<0.05),优良牧草比例由0.48上升为0.59;围栏封育后轻牧区金露梅灌丛的草场质量指数明显下降,重牧区草场质量指数明显上升。

关键词: 草原学, 生态, 封育, 轻牧, 重牧, 金露梅灌丛