Acomparation Of Dynamic Change On Highway Slope Communities During Recovery Process

Taking Xinyang to Nanyang section of Shanghai-Shanxi highway as the research object, selecting three kinds of soil slope area to establish plots, and each plot having seven plots of different vegetation types,this study observed and analyzed the changes in vegetation community characteristics in the process of highway slope restoration succession from 2005 to 2009. The results indicated: (1) In the natural succession of highway slope artificial rebuilt plant communities, the species diversity changed dynamically with the highest value appeared in the 3rd, 4th year, among which 57.14% had the maximum value of plant diversity in the 3rd year; the other appeared in the 4th year. Different plant communities had different diversity indexes. After the 3rd, 4th year of the natural successional process, the diversity indexes decreased. The reason was: The target plant in communities,AmorphafruticosaL., Trifolium repens Lin., Vitex negundo var. heterophylla, Pyracantha fortuneana, Euonymus fortunei var. radicans, Medicago sativa L.tec. had the strong competitive capacity expansion, taking the advantage status in the community; the existed species gradually developed into a stable and reasonable pattern, and the new species could seldom settle in, so the community basically reached steady state. (2) In the recovery process, the dominant species and the life form changed continuously. In the community's initial growth stage, Cynodon dactylon×C.transadlensis'Tifdwarf', Festuca arundinacead etc. often occupied the dominant position, but because of the weaker long-term competitive strength than other plants, so they were eliminated late in the growing process; AmorphafruticosaL., Trifolium repens Lin., Vitex negundo var. heterophylla, Pyracantha fortuneana, Euonymus fortunei var. radicans, and Medicago sativa L. etc. made a late comeback in the succession process, taking up a large living space, forming a assembling group which was help for the viability and competitive strength of the individual plant. (3) In the natural succession process,community biomass increased continuously, while there's no obvious linear relation between community biomass and community species diversity, so the community productivity was influenced slightly by the species diversity. In the recovery succession process, the community biomass mainly affected by the dominant species of the community; although the invasive species one biennial plants enriched the community species, yet their contribution to the community biomass was lower; and the biomass of the dominant species such as AmorphafruticosaL., Medicago sativa L., Trifolium repens Linn.etc. directly affected the biomass of the whole community. The shrub dominant species took up the upper space; the short herbaceous plants received less sunlight, and growing slowly, so the biomass was small; some well-adapted herbaceous plants such as Medicago sativa L.and Trifolium repens Linn.etc. grew quickly, and took up the space of the plot soon with a large cover degree; the invasive species enrich the species diversity of the community, while the increasing of the biomass mainly depended on the dominant species of the community.