Correspondence Analysis Of Plant Components And Soil Properties By Layers In Tidal Wetlands

The coastal wetland is an ecotone between land and sea.It is an ecosystem that is very sensitive to disturbance.On the long coastline of our country,the coastal wetland has the ecosystem service functions such as providing habitat,regulating climate and maintaining biodiversity.However,the environmental problems of ecological function degradation faced by coastal beach wetlands in China are becoming more and more serious.Due to the soil nutrient input caused by tides and the influence of water and salt gradients,the dominant species in Yancheng coastal wetlands are often distributed in strips along the elevation.Some of the small plant mosaics are randomly distributed in the mudflat and other plant communities to form mosaic communities.In particular,the gradual expansion of Spartina alterniflora population shows a distinct mosaic pattern with native species.This study took coastal wetland vegetation as the research object,and combines research plots,tidal flat vegetation and soil factors.We examined the soil properties in different soil layers between mosaic level and community level.At the same time,we examined the correspondence relationship between plant spatial patterns and soil factors.The results showed that:(1)In the mosaic community,the large difference was found for DS,TOC,TN,BD,Mz between different plant mosaics and different layers,in particular,S.alterniflora.The difference between the other plants is small.There was no significant difference in TP.The main difference in soil characteristics was observed between 0-10 and 10-30cm,and the difference decreased with the increase of soil depth.But,there is no significant difference in 30-60cm.(2)In the mosaic community,the influence of soil factors on mosaic components is the largest in 0-10cm and the influence decreased as the soil depth increased.The correspondence relationship between plant mosaics and soil properties decreased with the increase of soil depth.There were large differences in soil significant correlative factors between different layers.The significant correlation factor in 0-10cm is the most,and decreased as the soil depth increased.The correspondence at various depths between TN,Mz,TP and plant mosaics distribution is inconsistent.The correspondence at various depths between TOC,BD,DS and plants mosaics distribution is consistent.(3)The environmental factors of Yancheng wetlands have the characteristics of obvious overall gradient and complex and variable local micro-habitats.Therefore,there are differences in plant soil characteristics at different levels.In the plant community,the large difference was found for DS,TOC,TN,TP,BD,Mz between different plant mosaics and different layers,in particular,S.alterniflora.The difference between the other plants is small.(4)In the plant community,the influence of soil factors on community components is the largest in 0-10cm and the influence decreased as the soil depth increased.The correspondence relationship between plant communities and soil properties decreased with the increase of soil depth.There were large differences in soil significant correlative factors between different layers.The significant correlation factor in 0-10 cm is the most,and decreased as the soil depth increased.The correspondence at various depths between DS,TOC,TN,TP,BD,Mz and plant community distribution is consistent,but the effect is different.(5)The difference of DS between different levels was the most significant,followed by TP and MZ,while TOC,TN and BD were only significantly different in S.alterniflora plaque and S.alterniflora community.The separate interpretation rate of soil factors for different layers of CCA in plant mosaics/communities is different,and the trend is also the same.Among them,TN and BD have the largest difference,and DS and Mz have larger differences,while TOC and TP have smaller differences.In general,there are some similar differences in soil properties between different plant mosaics/communities,especially S.alterniflora.There are some similar differences in the correspondence relationships between soil characteristics and plant mosaic/community components.The difference is that:the correspondence at various depths between DS,TOC,TN,TP,BD,Mz and plant community distribution is consistent,and only TOC,DS and BD are consistent at the mosaic level.Considering that different soil factors have different effects on the vegetation succession process of tidal wetland,it is necessary to influence or induce vegetation succession trends and promote the ecological restoration process of degraded tidal flat wetlands by changing key soil factors.And based on the differences in the corresponding relationships between soil factors and plants,the key is to change the soil factors of 0-10 cm.In order to study the succession of plant communities in tidal wetlands,especially the ecological invasion of S.alterniflora and the restoration and protection of vegetation provide a theoretical reference.