Study On Vegetation Succession In Converting The Land For Forestry In Inner Mongolia Ordos

In recent years, due to land desertification has become increasingly prominent in Inner Mongolia Ordos, Conversion of Cropland to Forest become a local primary means for desertification controlling, therefore, there is positive theoretical and practical significance on this study. The study is about the pattern of vegetation, vegetation succession, soil variation and the recovery process and mechanism during Ecological Restoration.In this paper, Conversion of Cropland to Forest land in Inner Mongolia Ordos was investigated by plots and sampling method, important value, species diversity, similarity coefficient, population distribution patterns, ecological niche in abandoned farmland in different abandoned age were calculated. In this paper, by principal component analysis (PCA), canonical correspondence analysis (CCA), detrended correspondence analysis (DCA) and other methods, the relationship between communities and environmental factors, species diversity, growth and decline of species and dominance, changes in population pattern was analyzed, and the process of law and mechanisms of vegetation succession were studied. Main conclusions as follows:Through the study on Mechanisms and processes of vegetation succession, vegetation succession in sand area is divided into three stages.First stage:within 6 years abandoned land return to forests, abandoned land turned into semi-mobile dunes, the sand behalf plant is annual vegetation, population density is relatively small, the total coverage is generally 35% to 45%, and the height is low, no significant competition between population, the anti-interference ability is poor, spatial pattern of distribution is random, characterized communities are bamboo+bar Sha Tin quinoa and other communities. The vegetation succession trend is positive, but if disturbed it may stop or reverse to the totally different way.Second stage:6 to 14 years abandoned land return to forests, abandoned land turned into semi-fixed dunes, the sand behalf plant is annual and perennial plants, population density is moderate, the total coverage is generally 45% to 60%, and the height is low, spatial pattern of distribution is uniform, the anti-interference ability is general, characterized communities are Cynanchum+Euphorbia and other latex and other communities. The vegetation succession trend is positive, and it is the early part of rapid development of succession.Third stage:14 to 18 years abandoned land return to forests, abandoned land turned into fixed dunes, the sand behalf plant is Shrubs and perennials, population density is large, the total coverage is generally above 75%, and the height is high, spatial pattern of distribution is clumped, competition between species is fairly obvious, anti-interference ability is good, characterized communities are oil Artemisia+Hedysarum community and so on. The vegetation succession trend is reverse, and it is the regression of vegetation succession.