Restoration dynamics of community feature and diversity in degraded dry-grassland

Studied vegetation change of the degraded grasslands can provide knowledges on the restoration processes and mechnisms,reveal the factors liminting restoration,and is further a base for making ecological measures for fast restoration with the lowest input.The natural restoration of a degraded grassland dominated by Artemisia frigida,Thymus serpyllum and Cleistogenes squarrosa were researched in the Xilamuren dry-grassland zone,Inner Mongolia.Tresults showed that,through eight years banning grazing,the height of grassland community greatly increased;and its coverage,biomass and species had an increase,but species had a decrease in banning grazing five years.The species diversity and community evenness had a marked increas at first,and then a decrease;species richness and ecological dominance had a complex wavy change,the reason of this change was the grassland feature and people actions.Early in the banning grazing,intrusion of some annual and biennial plants and restoration of dominant species made plants community feature had an increase.Banning grazing seven years later,structure of the community tends to be more stable.