Effects Of Nomadic And Settled Grazing On Plant Diversity And Productivity Of Mountain Meadows In The Middle Of The Northern Slope Tianshan Mountains

The study area is situated in the mountain meadow grassland in the middle of the northern slope of Tianshan Mountain,with summer pasture and winter pasture serving as the primary grasslands,which is a typical grassland utilization method in which nomadic grazing and settled grazing coexist.By analyzing the relationship between nomadic grazing and settled grazing plant functional groups(height,cover,density,and biomass)and the relationship between variety and productivity,it provides a theoretical foundation for establishing sustainable grassland utilization.In summer and winter pastures,three nomadic and three settled herders were chosen,and two grazing intensities were established:light grazing(LG)and heavy grazing(HG).The association between quantitative properties of plant functional categories,grassland productivity,and grassland diversity and productivity was investigated,with the following results:(1)Under light grazing in summer and winter pastures,nomadic and settled grazing resulted in the lowest plant height,cover,and density of perennial grasses,perennial leguminous grasses,and other perennial grasses.Performance of plant cover:nomadic grazing>settled grazing.Performance of perennial grasses,perennial sedges,and weeds in winter pastures:settled grazing>nomadic grazing.Perennial sedge plant cover in summer pastures indicated:nomadic grazing>settled grazing;Perennial grass,perennial sedge,and other perennial grass plant cover in winter pastures indicated:settled grazing>nomadic grazing.(2)Under light grazing in summer and winter pastures,nomadic and settled grazing exhibited the highest plant dominance and diversity indices;Plant dominance index,diversity index,and evenness index revealed:settled grazing>nomadic grazing(3)The above-ground biomass of perennial grass plants under light grazing in summer pastures and winter pastures performed best under nomadic and settled grazing;The above-ground biomass of perennial sedge under heavy grazing performed best.The total above-ground biomass of nomadic and settled grazing plants decreased with increasing grazing intensity in both seasons.Under light and heavy grazing,the total above-ground biomass of settled grazing plants decreased by 10.34 and 3.77 percent in summer pastures and increased by 16.39 and 27.09 percent in winter pastures,respectively,when compared to nomadic grazing.(4)In both seasons,the below-ground biomass of nomadic and settled grazing plants declined with increasing soil depth.Under light grazing,the total below-ground biomass of settled grazing plants reached its maximum;Under light grazing and heavy grazing,the below-ground biomass of settled grazing plants in summer pastures decreased by 14.58 and 32.42 percent,respectively,compared with nomadic grazing;And increased by 7.32 and 11.52 percent in winter pastures under settled grazing,respectively.(5)The root crown ratio of nomadic and settled grazing plants in both seasonal pastures achieved its maximum under heavy grazing.Compared to nomadic grazing,light and heavy grazing reduced settled grazing in summer pastures by 4.20 and 42.11 percent,respectively;settled grazing in winter pastures increased by 3.86 and 4.16 percent,respectively.(6)The plant richness index,dominance index,and diversity index were strongly correlated with above-ground biomass under nomadic grazing and settled grazing in summer pastures and winter pastures,and exhibited a linearly positive relationship,i.e.the plant diversity index increased with increasing productivity.