Population Dynamics Of Both Leymus Chinensis And Carex Duriuscula In The Series Of Restoration Succession In Northeast Degradation Grassland

Changes in the population dynamics of Leymus chinensis，as the dominant species， andCarex duriuscula, as the main companion species, has an important instructive functionduring the degradation and restoration succession process in Northeast Songnen Plain. Thisstudy took artificial planting L. chinensis experimental populations of different initialdensities in C. duriuscula background community, and natural L. chinensis and C. duriusculapopulations in different successional series as the objects, after observation in a growingseason, statistical analysis on the quantititative dynamics and the indicators related to the agestructure of L. chinensis populations in the experimental and natural plots, on mutual dynamicof quantitative characteristics of L. chinensis and C. duriuscula, which revealed the law of thepopulation dynamic changes of degraded grassland in the degradation and restorationsuccession process, and further improved the recovery succession theory, to provide atheoretical reference to the practice of recovery succession of the degraded grassland.Throughout the growing season, artificial planting L. chinensis experimental populationsof different initial densities in C. duriuscula background community constantly producedsub-strains through vegetative propagation, the number of tillers of L. chinensis increased tothe extent of the exponential function while C. duriuscula increased and then decreased tothe extent of the quadratic function, reaching a very significant level; The number of tillers ofnatural L. chinensis and C. duriuscula populations in different successional series reached avery significant difference to the extent of the exponential function or logarithmic functionduring5-9except7, L. chinensis population continued to increase while the C. duriusculapopulation decreased.The number and biomass were two age classes, for the tillers of L. chinensis populations.significantly increaseing in the age structure, they would continue to increase not onlyartificial planting L. chinensis experimental populations of different initial densities in C.duriuscula background community but also natural L. chinensis populations in differentsuccessional series in each month.Rhizome cumulative length and root biomass and the potential population of L. chinensisexperimental populations were composed of two age classes, were increaseing in the agestructure, while rhizome cumulative length and root biomass of natural L. chinensispopulation consistd of three age classes, were stable in the age structure, the potentialpopulation of natural L. chinensis populations consistd of three age classes, was increaseing inthe age structure. L. chinensis rhizome has a strong expansive capacity, the potentialpopulation was ready for the update of the population in the following year to theexperimental and natural L. chinensis populations.The increasing trend of the number of tillers and expansive capacity of the rhizome andthe number of bud in the potential population were dominated regardless of the L. chinensis experimental populations in different initial density, or natural L. chinensis populations indifferent successional series in C. duriuscula background community. Thus the number of L.chinensis would continue to increase and became the dominant species in the process ofrestoration succession.