Effects of Grazing on the Biodiversity and Productivity of Leymus secalinus Communities
In order to understand the effects of grazing on Leymus secalinus communities,the biomass and species diversity dynamics of L.secalinus communities were investigated throughout the growing season under five years fenced and free-grazing sites,respectively.Results showed that plant communities were dominated by L.secalinus throughout the growing season in both fenced and free-grazing plots.Species richness index in the grazing plots was significant higher than that in the fenced plots.In addition,diversity index and evenness index did not show the same trend at different periods.Aboveground biomass,height,coverage,species richness,diversity index and evenness index of L.secalinus communities increased firstly and then decreased in the entire growing season.Grazing significantly reduced the aboveground biomass of L.secalinus communities.Throughout the growing season,the coverage of community decreased by 31.82％ and the plant height reduced to 36.37 cm after grazing.Belowground biomass in fenced plots appeared two peaks,including July (4148.4 g · m 2) and September (4359.27 g · m-2),while the maximum belowground biomass in free-grazing plots happened in August for 2559.28 g · m-2.With increasing soil depth,belowground biomass proportion of L.secalinus communities gradually reduced,which of fenced and free-grazing plots were 75.64％ and 77.37％,respectively.All results indicated that moderate grazing had significant positive impact on the species diversity of L.secalinus communities,while unreasonable grazing decreased the coverage,height and biomass of plant communities,so fenced grazing significantly promoted stability and sustainable development in L.secalinus grassland.
NETL
NSTL
万方数据
维普
