The Response Of The Structure Of Plant Community, Vegetation Productivity And Soil Factors On The Altitude Gradient Changes At Laji Mountain Area Of Qinghai Province

This research is conducted on the Laji mountain of Guide County, Qinghaiprovince. Based on the field survey method, we set up a total of9survey plots alongelevation gradient of the mountain (3100-3920m), and analyses plant communitytypes, the species composition of community, species diversity index and vegetationproductivity and the correlation between the above parameters and elevation. Theresults show that:1.There are96plant species on the plant communities of Laji mountain region.Plant communities is characterized by relatively poor plant species, simplecommunity structure, low grass layer and evenly distribution due to the high altitudeand the bad weather condition of this area.2.Species richness first increas and then decreas with the increased elevationgradient, and in mid-elevation areas reach the maximum value, reach max value at3410m on sunny slope and at3315m on shady slope.3.The total aboveground biomass of plant communities show the trend firstdecreased and then increased with the increasing elevation gradient, totalaboveground biomass in shady and sunny show a highly significant negativecorrelation with the elevation gradient (P<0.01).The total underground biomass insunny slope show an increasing trend with the increasing altitude(P<0.01); the totalunderground biomass of the shady slope tend to decrease with the increasingaltitude(P>0.05). The total aboveground and belowground biomass in sunny slopetend to increase with the increased elevation gradients, and showed a highlysignificant positive correlation with the elevation gradient (P<0.01); the totalbiomass in shady slope tend to decrease with the elevation gradients, and show ahighly significant negative correlation with the elevation gradient (P<0.01).4.Soil bulk density in shady slope showed a highly significant positivecorrelation with the elevation gradient (r=-0.583,P<0.01）; Soil bulk density insunny slope showed a highly significant negative correlation with the elevation gradient (r=-0.393，P<0.01).5.Soil water content in shady showed a highly significant negative correlationwith the elevation gradient (r=-0.393，P<0.01),soil water content in sunny showeda highly significant positive correlation(r=0.857，P<0.01）.Soil temperature in sunnyshowed a highly significant negative correlation (r=-0.829，P<0.01).