Herbaceous Community Characteristics And Dynamics Of Wetland In Ineer Mongolia Steppe Zone

Wetlands of Inner Mongolia steppe zone are mainly typical plateau wetlands.Through the collection and arrangement of wetland flora and herbaceous vegetation data in Inner Mongolia steppe zone as a whole,combined with the ecological succession of wetland communities in Inner Mongolia steppe zone,and the relationship between communities diversity and climatic factors of wetland vegetation.Concluded as follow: 1.There are 1238 species of vascular plant in the wetland in Inner Mongolia,belonging to 99 families and 428 genus.Herbaceous plant is main type and mesophytes is dominated.Areal-types of family of vascular plant is predominated by the worldwide distribution family,and genus are predominated by temperate distribution type.There are 18 endemics,7 protected plants(the first batch)and 10 characteristic species of wetland in Inner Mongolia.2.According to subject of plant Communities-Principles of Ecological Classification,herbaceous communities of wetland in Inner Mongolia are divided into 3 vegetation types and 7 vegetation subtypes,and finally divided into 67 formations.Form.Calamagrostis pseudophragmites,Form.Carex duriuscula,Form.Achnatherum splendens,Form.Puccinellia distans and Form.Phragmites australis,which distribute are large and widespread.3.Water and salinity are the mainly driving forces for the ecological succession of herbaceous communities of wetland in Inner Mongolia.When influenced by human factors or climatic drought factors,such as grazing,water source throttling and so on,the increased evaporation of soil moisture and the accumulation of soil surface salt increases,and soil physical and chemical characteristics changes,lead to the succession of communities will occur in different directions.4.Form.Carex appendiculata(commonly known as tato swamp)is the most representative swamp community in the land-water transition zone in steppe zone,due to irrational human activities and climatic changes,the community characteristics are prone to change,and the community and soil physical and chemical characteristics changed in different degradation stages.Changes are as follows:The degradation of Carex appendiculata tato swamp leads to changes in community species composition,the dominant species of Carex appendiculata gradually withdraw from the community,perennial forbs,Carex duriuscula are gradually increased and evolved into dominant species.The value of α diversity is the highest in the light degraded stage and the lowest in the CK stage;β diversity reflects a gradual decrease in community similarity and a gradual increase in species replacement rates.As the degree of degradation increases,the organic carbon content decreases;the degradation of Carex appendiculata tato swamp have significant influence on the content of soil organic carbon in 0-10 cm soil layer.As the degree of degradation increases,the value of soil pH from alkaline to neutral;degradation have no significant effect on pH value in the vertical direction of soil layer.Soil electrical conductivity reflect soil salinity,the degradation of Carex appendiculata tato swamp have significant effect on Soil electrical conductivity in 0-20 cm soil layer.As the degree of degradation increases,in other words,the communities gradually becomes steppe,then lead to decrease of Soil electrical conductivity values,the decrease of soil salinity.5.The species richness of wetland herbaceous vegetation increased with the increase of longitude,latitude and mean annual rainfall,and decreased with the increase of mean annual temperature and altitude.The Shannon-Weiner index increased with the decrease of mean annual temperature and the increase of longitude and latitude.The mean annual precitition and altitude have little effect on the changes of the Shannon-Weiner index.Mean annual temperature,mean annual rainfall,altitude,longitude and latitude have no significant effect on Simpson index and Pielou index.