Ecological Adaptation Of Vegetation And Characteristics Of Plant Resources In Otindag Sand Land

Otindag Sand Land, located in the middle of Xilin Gol plateau, is the largest sand land in dry steppe zone of China. Long-term immoderate use had triggered a series of environmental problems such as grassland degradation, activation of fixed sand dunes, sand land desertification and sandstorm breakout. So, it is very urgent to prevent further extension of desertification in Otindag Sand Land. The aim of this research is to understand the ecological relationship between sand vegetation and environment, adaption charactristics of psammophilous plants to sandy environment and feature of plant resources in Otindag Sand Land, and further to provide theory evidence for selection optimal sand-fixation species and planning feasible process of vegetation restoration in desertification control. This thesis includes: 1 classification and ordination analysis of plant communities in inter-dune lowland in Otindag Sand Land; 2 the effects of sand burial on seedling development of Caragana intermedia; 3 analysis the feature of plant resources in Otindag Sand Land.The results of TWINSPAN classification and DCA ordination of herbaceous communities in inter-dune lowland showed that there are four main types of plant communities with different features, and that salinity of soil and related soil moisture has significant effect on the distribution of herbaceous communities. Sand burial is one of the main factors that affect seedling survival in sand land. Caragana intermedia is a psammophilous shrub and one of the commonly occurred species in fixed and semi-fixed sand dunes in Otindag Sand Land and MU US Sand Land. To learn the effect of sand burial on seedling survival and growth of the species, seed-originated seedlings of Caragana intermedia grown in greenhouse for a month were buried by sand in an experiment with different treatments: control; part of theabove ground section was buried by sand; all of the above ground section was buried by sand. The result shows that partial sand burial of above ground section may not affect growth and development of Caragana intermedia seedlings, whereas full sand burial of above ground section may do. It can be suggested that Caragana intermedia should be a sand burial tolerant species.Otingdag Sand Land has abundant plant resources. The number of seed plant species occurred in Otindag Sand Land is about 952, which are contained in 348 genera of 75 families. Composite and gramineousness are the two biggest families; In the life-form spectrum, herb is the main life form, which has 828 species and accounts for 86.97% of the total species; Mesophytes have the greatest number in water ecological form, which has 577 species accounting for 61.1% of the total species; xerophyte is in the second order, with 291 species accounting for 30.8% of the total species;In addition, most species can be used for grazing, sand fixation and medicine.