THE CLASSIFICATION AND ORDINATION OF ECOLOGICAL ELEMENTS IN MAOWUSU SANDY GRASSLAND LANDSCAPE
毛乌素沙化草地景观生态分类与排序的研究

Maowusu sandy grassland is an ecotone in the transitional zone of animal husbandry and agriculture in North China. In this study,a quantitative hierarchical classification is committed on the sandy grassland landscape ecological elements with TWINSPAN,which is widely used in vegetation science. Then a sandy grassland ecological classification system is drawn. DCA, which has a similar algorithm in comparison with TWINSPAN, is applied in the ordination of sandy grassland landscape ecological elements. Other multivariate analysis such as stepwise regression is done to clarify the relationship between the classified landscape ecological types. Maowusu sandy grassland is rich in landscape ecological types. Groundwater-table, sand depth, and parent material types are the key factors controlling the genesis and succession of the landscape ecological types. Finally a landscape ecological succession module of Maowusu sandy grassland is given. According to this research,TWINSPAN and DCA are useful in landscape ecological quantitative classification and ordination.