Study On Fencing Effects Of Seriphidium Transiliense Desert Grassland

In present paper,taking the Seriphidium transiliense desert grassland in Manas County and Hutubi County as research object,the monthly dynamic variationsof plant community quantitative characteristics and plant diversity between fencing(2～3a)and grazing plots in 2017 and 2018 were measured by using the methods of field survey and sampling,which aimed to clarify the effects of short-term fencing,and explore the intermonthly and interannual dynamic changes of plant community characteristics.These results can provide a theoretical basis for the evaluation of vegetation restoration effects of degraded desert,and also provide some references for scientific management and optimization of production mode.The main results are as follows:(1)Compared with grazing plots,the important value(Ⅳ)of perennial herb improved obviously after fencing 2～3 a,while the Ⅳ of sub-shrub,ephemeral and ephemeroid plant were not significant.Regardless of whether desertwas fenced or not,the sub-shrubs occupied an absolute dominant position.The Ⅳ of the sub-shrubs showed a trend ofrisingandthenkeep it steadyin both fencing and grazing plotsfrom May to September,while the Ⅳ of perennial and annual herbs among months were not change remarkly,and ephemeral and ephemeroid plant only appeared in May.(2)The height,coverage and biomass of community were increased significantly by 15.42%～194.71%,21.76%～285.91%,75.31%～810.60%(P<0.05)after fencing 2～3 a.However,the density of community were not obvious differences(P>0.05).In addition,the community quantitative characteristics among months were different:the height of community increased firstly and then tended to stabilize with months in both fencing plot and grazing plot,and the height in May were significantly lower than that in July and September(P<0.05).While the density of community significantly decreased firstly and then tended to stabilize,and they in May were significantly higher than that in July and September(P<0.05).Moreover,the coverage of community showed a trend of declining and then rising with months in the fencing plot,but the biomass is contrary to density,and showed a trend of rising and then declining.In grazing plots,the difference of the coverage and biomass were not significant in different months(P>0.05).(3)The Margalef richness index(Dma),the Pielou evenness index(E),the Simpson diversity index(D)and the Shannon-Wiener diversity index(H)of the S.transiliense desert grassland were not significant change after fencing 2-3 a(P>0.05).The trends of Dma,D and H from May to September were similar and all showed remarkable reduced before stabilization.The Dma,D and H in May were higher significantly than that in July and September,and were not significant between July and September(P>0.05).In addition,the E among months had no obvious change.The above results indicated that fenceing(2～3 a)can improve significantly the height,coverage and biomass of community in S.transiliense desert grassland,which was beneficial to improve grassland quality.However,the effects of fencing on plant biodiversity were weak.In conclusion,short-term fencing(2～3a)is beneficial to vegetation restoration in degraded deserts.