季节性休牧对草甸草原植物群落空间分布格局的影响

Effects of Seasonal Grazing Rest on Spatial Distribution Pattern of Plant Communities in Meadow Steppe

为探索季节性休牧对植物群落及空间异质性的影响,本研究对内蒙古草甸草原季节性休牧样地进行网格采样,该草地设置连续放牧CG、早期休牧RE(6月15日—7月15日)、中期休牧RM(7月15日—8月15日)和晚期休牧RL(8月15日—9月15日)4种管理方式,结合统计学分析方法研究不同休牧时间处理下植物群落空间分布格局。结果表明:RM地上生物量、盖度和高度显著高于其他组;RE和RL的Shannon指数和物种丰富度显著高于CG和RM;RM增加了禾草生物量占比;CG和RM生物量分布均匀;RE表现为随机分布,RL表现为斑块分布;四种放牧方式的物种丰富度表现为斑块分布;CG和RM物种均匀度指数表现为斑块分布;RE分布均匀;RL均匀度表现为随机分布。综上所述,RM能够提高植物群落地上生物量,促进植物均匀分布、而RE和RL能够增加物种多样性。

To explore the effects of seasonal grazing rest on plant communities and spatial heterogeneity,grid sampling was conducted on an experimental grazing platform in Inner Mongolia meadow grasslands where seasonal grazing rest had been carried out over the past five years.The grazing platform was set up with four management modes:they were continuous grazing CG,early grazing rest RE(June 15—July 15),mid grazing rest RM(July 15—August 15)and late grazing rest RL(August 15—September 15).Geostatistical analysis method was used to test the effects of different grazing treatments on plant community characteristics and their spatial pattern.The results show that the above-ground biomass,coverage and height of RM significantly exceeded those of other groups;the Shannon diversity index and species richness of RE and RL were markedly higher than those of CG and RM;RM increased the relative aboveground biomass of grasses;the spatial heterogeneity of plant communities was uniformly distributed in the above-ground biomass of CG and RM plants.Patches of RE plants distributed randomly,and that of RL plants showed a patchy-type of spatial pattern;the spatial distribution patterns of species richness were similarly patchy;species evenness in CG and RM showed a patchy-type of spatial pattern,RE present a uniform distribution,whereas Pielou index of RL distributed randomly.In summary,RM can increase the above-ground biomass of plant communities and promote their uniform distribution,while RE and RL can increase species diversity.