Effects Of Grazing Exclusion On The Functional Traits Of Dominant Plants In Desert Steppe

Plant functional traits are plant traits that are closely related to plant growth and survival and have an indicator of ecosystem function.Studying the changes of plant functional traits is of great significance to grassland ecological construction.In the desert steppe of Ningxia,choose unsealed(FYO),closed 3 years(FY3),7 years(FY7)and 15 years(FY15)grassland,and the dominant plants Agropyron mongolicum and Stipa breviflora,Lespedeza potaninii,Glycyrrhiza uralensis important value,niche breadth,leaf functional traits,root function traits;plant functional traits,functional traits and important values and niche,The relationship of soil factors was analyzed.The main conclusions are as follows:(1)Agropyron mongolicum andGlycyrrhiza uralensis were the highest in FY7;the niche breadth of the other three species except Stipa breviflora decreased with the increase of the number of years of fencing.(2)Lespedeza potaninii TWC is the highest in FY7,RWC is the highest in FYO,TWC and RWC of Agropyron mongolicum are the lowest in FY3.With the increase of years of enclosure,the single leaf area,dry weight and leaf width of Glycyrrhiza uralensis and Stipa breviflora increased,but the single leaf area and dry weight of Lespedeza potaninii decreased.The SLA of Agropyron mongolicum and Stipa breviflora was the highest in the past 7 years;the LDMC and leaf P of Glycyrrhiza uralensis and Agropyron mongolicum decreased with the increase of the number of years of enclosure.The N:P of Agropyron mongolicum and Stipa breviflora increased with the increase of the number of years of enclosure.(3)The total root length of Glycyrrhiza uralensis and Agropyron mongolicum was the lowest in FYO;except for the cattle branch,the average root diameter FYO of the three species was the highest;the root surface area and root volume of Stipa breviflora were the highest in FYO.With the increase of the number of years of enclosure,the SRA of Glycyrrhiza uralensis,Agropyron mongolicum and Stipa breviflora,Glycyrrhiza uralensis and Agropyron mongolicum have increased.The root biomass ofGlycyrrhiza uralensis and Agropyron mongolicum was 0-40cm,which was the highest in FY7.The root N content of the four species was at the maximum at FY15;the root P content of the Lespedeza potaninii decreased with the increase of the enclosure years.The ratio of nitrogen to phosphorus in the three dominant plants except for Stipa breviflora showed a decreasing-increasing trend with the increase of the number of years of enclosure.The distribution of Glycyrrhiza uralensis N showed a decreasing trend with the increase of the number of years of enclosure;the grass of Agropyron mongolicum increased with the increase of the number of years of enclosure.The distribution of Stipa breviflora decreased with the increase of the number of years of enclosure.(4)There is a certain correlation between functional and functional traits of different families,and plant functional traits are affected by soil nutrient content.Some functional traits of dominant species are closely related to their important values and niche breadth.Studies have shown that with the extension of the years of encapsulation,the functional traits of dominant species change,indicating that the enclosure has improved the ecosystem environment,and plants have formed certain growth strategies.However,due to factors such as the genetic nature of the plant and the competition of species,the functional traits did not show a linear trend.