Northeast Degraded Grassland Restoration Succession Process Of Population Growth And Decline Of The Experiment Together Research

The number dynamics of Leymus chinensis population and Carex duriuscula population have important indicative function in the process of degeneration and restoration succession in the Songnen meadows of China. Research on the dynamics of L. chinensis and C. duriuscula populations, correlative indexes of age structure and the statistics and quantitative analysis of competition ability of two populations in different proportions of L. chinensis and C. duriuscula experimental populations, which were transplanted, in two growing seasons. The mutual growing and declining laws of two populations would be expounded in the process of meadow restoration succession. The succession theory would be enriched. These would offer a theoretical guidance to restoration practice of meadow ecological system. The results indicated:In different initiative proportional experimental spots L. chinensis and C. duriuscula populations gave birth to seedlings by vegetative propagation all the time in this year. L. chinensis, C. duriuscula and their total had same growth and decline regulations of exponential function in their vegetative tillers at 0.01 level. The average increasing rates of L. chinensis were faster than C. duriuscula from 1∶1 to 1∶5 experimental spots. Two populations had almost same increasing rates in single species spots. The actual increasing rates of two experimental populations in the first year were higher than the second year. The density of L. chinensis and C. duriuscula populations increased 32.31 times and 24.48 times in the first year and increased 2.52 times and 2.30 times in the second year. Proportional composition of L. chinensis and C. duriuscula occurred radical changes in mixed spots in two growing seasons. The proportion of L. chinensis obviously ascended and C. duriuscula obviously descended. The tillers of L. chinensis consisted of three age classes and C. duriuscula did two ~ three age classes in every spots after two years. C. duriuscula population was stable in singe species spot and two populations were expansive age structures in other spots. The tiller nodes of L. chinensis and C. duriuscula could propagate several generations. The rhizomes of L. chinensis were composed of two age classes and C. duriuscula did one ~two. Two populations were obviously expansive age structures in every spots. The expanding ability of L. chinensis rhizomes was stronger than L. chinensis rhizomes. The total of L. chinensis potential populations exceeded the maternal tillers in this year by a long way and C. duriuscula did only in 1∶6 spot. L. chinensis would predominate to population renewal in the next year.L. chinensis was dominant in average vegetative propagated rate, rhizome expansive ability and the storage of potential population in mixed spots. These determined that the competition ability of L. chinensis would be superior to C. duriuscula. L. chinensis would replace gradually C. duriuscula and become dominant species of the community.