Abstract: A study of moderate grazing and mowing to the quantitative characteristics of Stipa grandis populations and communities of Inner Mongolia Grassland Ecosystem Research Center reveals that the grass’s height of reproductive and vegetative tillers, as well as the leaf length of the vegetative tillers in the moderate grazing sample plot decreased significantly compared to those of the mowing sample plot,while the fractal dimension of aboveground biomass of the reproductive tillers and C/N ratio of the vegetative tillers leaves of the moderate grazing plot increased markedly. All this could be viewed as a growth strategy of S.grandis when disturbed by grazing. The plant height of the mowing sample plot followed the normal distribution model, while that of the moderate grazing sample plot showed a logarithmic normal distribution with peaks leaning leftward. In addition, the importance of value of S.grandis in the communities of the moderate grazing sample plot increased noticeably, while the species diversity of the mowing sample plot was more marked than that of the moderate grazing sample plot.

Key words: Stipa grandis, Moderate grazing area, Mowing area, Biomass, Fractal dimension, Frequency distribution

摘要： 研究大针茅草原在中牧区和割草区种群和群落数量特征.结果表明:与割草区相比,中牧区大针茅生殖枝和营养枝株高和叶长显著减小,生殖枝生物量的分形维数显著增大,营养枝叶片内C/N比显著增加,这是放牧干扰后生长变化的度量指标;割草区株高呈正态分布而中牧区则为峰值左偏的对数正态分布;中牧区大针茅在群落中的重要性显著增大,而割草区物种多样性则显著高于中牧区.

关键词: 大针茅, 中度放牧区, 割草区, 生物量, 分形维数, 频度分布