Correspondence Analysis Of Plant Composition And Soil Properties In Yancheng Coastal Wetlands

Coastal wetlands are regional ecological barrier of vital importance,which play an irreplaceable role in regulating climate,providing rare species habitat,protecting biodiversity and maintaining ecological balance.The growth of coastal wetland plants has changed the material cycle and soil environment,and the soil properties in turn will affect the growth and reproduction of plants.Coastal wetland plants and soil interact and interconnect with each other,forming a unique coastal wetland ecosystem.There is an obvious corresponding relationship between plants and soil factors in coastal wetlands,but in different community types,the corresponding relationship is quite different.The study of the relationship between plants and soil properties in different community types and the analysis of the relative importance of different soil factors on the community composition characteristics play an important role in exploring the function characteristics of different soil factors and identifying the key soil factors affecting the community composition characteristics.At the same time,it also provides a theoretical basis for the ecological restoration of coastal tidal flats based on the regulation of soil habitat.In this study,the core area of Jiangsu Yancheng Wetland National Nature Reserve was selected.The typical plant communities including Spartina alterniflora,Scirpus triqueter,Suaeda salsa,Phragmites australis and two mosaic communities including Spartina alterniflora-Scirpus triqueter-P.australis mosaic community(SSP)and P.australis-Scirpus triqueter-Suaeda salsa mosaic community(PSS)were selected as sampling sites.The plant species data of each sampling point were recorded and the soil factors such as soil salinity(SS),bulk density(BD),grain size(MZ),total organic carbon(TOC),total nitrogen(TN),total phosphorus(TP)and available phosphorus(AP)in 0-10 cm,10-30 cm,30-60 cm deep soil layers were measured.The soil properties of different plant patches in the monodominant and mosaic communities were analyzed by one-way ANOVA,and the corresponding relationship between soil factors and plant components in monodominant and mosaic communities was analyzed by CCA.The purpose of this study was to explore the key soil factors affecting the composition of plant communities in Yancheng coastal wetlands,and the results revealed that:(1)The differences of soil characteristics among different plant patches in monodominant plant communities were generally greater than those among different plant patches in mosaic communities,but the differences of main soil physical and chemical indexes among different soil layers were more significant in mosaic communities.In general,there were significant differences of SS,MZ among different depths in the monodominant communities and mosaic communities,and was no significant difference of TP.And there were significant differences of TOC,TN,AP and BD among different depths only in mosaic communities.(2)The corresponding soil characteristics of the same plant are relatively consistent in the monodominant community and mosaic community.The contents of TOC,TN,TP and AP in the three soil layers of Spartina alterniflora patches were higher than those of the other three plant patches,while the contents of BD were lower than those of the other three plant patches.The contents of SS in surface soil of Suaeda salsa patches were the highest in both monodominant and mosaic communities.(3)The correlation between soil factors and plant distribution was the highest in the surface layer in monodominant communities and mosaic communities.With the increasing of soil depths,the corresponding relationship between plants and soil factors weakened,and the weakening range was larger in mosaic communities.(4)The corresponding relationship between plant components and soil factors was different due to the community types and soil factors.SS had a high consistency with plant components in monodominant communities and mosaic communities,and the simple effect of SS in surface soil ranked high in both monodominant and mosaic communities.The corresponding relationship between TOC,AP,MZ and plant components was stronger in monodominant communities than in mosaic communities,and the simple effect of TOC,AP,MZ ranked higher in monodominant communities.The corresponding relationship between TN,BD and plant components was relatively weaker in the monodominant communities,and the simple effect of TN,BD ranked higher in mosaic communities.The corresponding relationship between TP and plant components was weak in both monodominant and mosaic communities,and the simple effect of TP was relatively low in monodominant and mosaic communities.According to the results of the relative consistence of the corresponding relationship between plant components and soil factors and the simple effects of soil factors on the characteristics of plant components,we held that SS was the key soil factor to affect the spatial distribution of coastal vegetation.TOC,AP and MZ played a leading role in the formation of plant community types and spatial distribution,while TN and BD are more likely to change due to the interaction between plant patches and soil.TP had a relatively low impact on the composition of vegetation in the study area.