Effects Of Different Recovery And Improvement Measures On Degraded Leymus Chinensis Steppe Community And Plant Functional Traits

In order to further explore the changes of degraded Leymus chinensis steppe community and plant functional traits after restoration and improvement measures,this study was carried out in the Grassland Ecology Research Base of Inner Mongolia University,Xilinhot City,Inner Mongolia,through shallow tillage,cutting roots and fence enclosure.The degraded Leymus chinensis steppe treated by the measures was taken as the research object.By measuring the functional traits of the dominant species under different restoration and improvement measures,and obtaining the aboveground biomass and underground biomass of the community in the same period,the following conclusions were drawn:1.Three restoration and improvement measures significantly increased the 9 traits of Leymus chinensis,including plant height,aboveground biomass,stem leaf ratio,stem weight,stem diameter,totalleaf length,leaf number,total leaf weight,leaf mass per area.The sensitivity of Leymus chinensis under different restoration and improvement measures was different,and compared with C.serrata and Stipa breviflora,Leymus chinensis responded more strongly to restoration and improvement measures.There was a significant correlation between the indicators of Leymus chinensis under different restoration and improvement measures.2.The effects of three restoration and improvement measures on the traits of Cleistogenes squarrosa showed irregular effects.Overall,the eight indicators of plant height,aboveground biomass,canopy coverage,total leaf area,total leaf weight,stem weight,leaf dry matter content,leaf allocation showed an increasing trend.Compared with Leymus chinensis,Cleistogenes squarrosa is less sensitive to the response to restoration measures.Similar to Leymus chinensis,there was a significant correlation between the traits of Cleistogenes squarrosa under different restoration and improvement measures.3.In this study,after 7 years of shallow tillage improvement measures,there were no Stipa krylovii in the plot;the two restoration and improvement measures of cutting roots and fences significantly increased the individual traits of Stipa krylovii,including the aboveground biomass,total leaf weight,stem weight.The dry matter content of the leaves was significantly reduced under the two restoration and improvement measuresof cutting roots and fences.Compared with Leymus chinensis,Stipa krylovii is less sensitive to the response of cuttings and fences.4.There are trade-offs between the three individual traits of Leymus chinensis,Cleistogenes squarrosa and Stipa krylovii under three restoration and improvement measures.Compared with free grazing,cutting roots and fencing enclosures changed the trade-off relationship between the functional traits of Leymus chinensis.Three restoration and improvement measures changed the trade-off relationship between the functional traits of Cleistogenes squarrosa,and the fenced fencing changed the Stipa krylovii Trade-off relationship between functional traits.The trade-off relationship between rhizomatous grasses and clump-type grasses is different under the same treatment.5.The three restoration and improvement measures have increased the aboveground biomass and underground biomass of the community to different extents,but have a reduced effect on the community density.The analysis of community species diversity showed that all the three restoration and improvement measures could reduce the species richness,diversity,dominance and evenness index.