Plant Community Differentiation Characteristics And Its Environmental Explanation In Xiaosugan Lake

The spatial diversity pattern of wetland plant communities is the result of ecological processes such as species characteristics and inter-species interactions in heterogeneous habitats.To study the response of the spatial distribution pattern of plant communities in inland salt marsh to soil water and salt is of great significance to understand the environmental plasticity mechanism of plant communities in salt marsh.In order to study the Xiaosugan lake wetland plant community spatial distribution pattern and the relationship between the main environmental factors,the Xiaosugan lake nature reserve,considering the wetland types,plant cover a variety of factors,such as to set up the 45 samples,on the basis of community learning in the field investigation,with Xiaosugan lake wetland natural vegetation as the research object,separately the number of classification and sorting,species diversity,dominant species of interspecific relationship research,the results are as follows:?1?The main wetland types in the study area include inland salt marsh,seasonal saltwater marsh,marshy meadow,herbaceous marsh and fresh water spring.Among them,inland salt marsh is the wetland type with the largest distribution area,and there are significant differences in soil physical and chemical properties among each wetland type.The vegetation was mainly gramineae,sedge and compositae,and the main plants were Phragmites australis?Leymus secalinus?Saussurea salsa?Sophora alopecuroides?Kobresia capillifolia and Scirpus pumilus et al.Different types of wetland have different plants.?2?The results showed that there were six main community types of wetland plants in Xiaosugan lake namely:Phragmites australis+Leymus secalinus;Leymus secalinus;Sophora alopecuroides+Saussurea salsa;Saussurea salsa+Leymus secalinus;Triglochin palustris+Triglochin maritima;and Kobresia capillifolia+Carex altaica.There were significant differences in the biological characteristics of each plant community.The average height and abovemeal biomass of Phragmites australis+Leymussecalinus community were the highest in all communities,respectively 103.66cm and 1809.73 g/m².The average coverage of Kobresia capillifolia+Carex altaica community was 67.5%.The aboveground biomass of Triglochin palustris+Triglochin maritima communities was the lowest among all communities,which was only 193.98g/m².Leymussecalinus?Sophora alopecuroides+Saussurea salsa and Saussurea salsa+Leymus secalinus are mainly distributed in salt marsh,and their average height,average coverage and average aboveground biomass are in the middle level.Each community showed significant spatial difference by adapting to the movement law of soil water and salt in its own region.?3?The comparison of species diversity among the six community types showed that the diversity index?H'?and evenness index?J?of the communities of Triglochin palustris+Triglochin maritima were the highest?1.85 and 0.89,respectively?,but the dominance index?C?was only 0.19,which was the lowest among all communities.The diversity index?H'?and evenness index?J?of Leymussecalinus community were the lowest among all communities,only 0.33 and 0.48,but the dominance index was the highest,reaching 0.68.?4?Advantages of Xiaosugan lake wetland,according to the analysis of the connection between plants,integrated?² test and the calculation of the AC,PC index,were very significant or significant correlation found between dominant species of the less,the overall correlation between species is weak,this is probably due to habitat differences,there are the inland salt marshes and freshwater spring season,the river,and the salt marsh,swamp meadow and marsh habitat,and salt-tolerant plants with A greater difference between meadow plant life habits.At the same time,the positive correlation logarithm of 66 pairs of dominant species was less than the negative correlation logarithm,which indicated that the plant community was not stable enough.?5?The acquired by using DCA sorting result and TWINSPAN classification community types,basic instruction sorting result is good,can reflect the plant community characteristics,sort and CCA figure obviously reflect the ecological significance of sorting axis,the first axis prominent reflect the change of the moisture gradient,from left to right along the first axis,the change of community types and characterization of the changes of wetland types;The second axis mainly shows the influence of soil Cl^-and Ca²⁺and other key ions on plant community distribution.Soil moisture content,soil Cl^-,Ca²⁺and groundwater depth have a great influence on the spatial distribution of plant communities in the salt marsh in Xiaosugan lake.