Vegetation composition of Momoge wetland and its implications for succession in alkaline wetland

Momoge is a typical alkaline wetland in Songnen Plain. Although the Momoge wetland serves as a vital habitat in the global flyway of white crane ( Grus leucogeranus ), the changes of vegetation composition and related environmental factors in this region during its degradation remain unclear. Based on the vegetation survey and soil sampling in the field, Two-Way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA) were used to classify the vegetation. Detrended Canonical Correspondence Analysis (DCCA) was also used to explore the relationship between vegetation composition and environmental factors. The results are: vegetation in the Momoge wetland is classified into nine types, i. e. Leymus chinensis community, Polygonum hydropiper community, Scirpus planiculmis community, Potentilla anserina community, Phragmites australis community, Digitaria ciliaris community, Setaria viridis community, Chloris virgata community and Artemisia sp. community, of which the C. virgata community and the Artemisia sp. community are of high prevalence. Vegetation in the Momoge wetland is dominated by communities of mesophytes, indicating that degradation is ongoing and the vegetation of this wetland can be classified as degraded meadow. The fundamental cause for vegetation differentiation in this wetland is the change of water regime though soil PH value, conductivity and the amount of organic matter are identified as the significant environmental factors associated with it. A certain degree of disturbance caused the prevalence of the C. virgata community, independent of previous vegetation or over-grazing.