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

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