The succession patter of saltmarsh vegetation in south coast of the Hangzhou Bay and analysis of its influencing factors

MAO Yican; LIAO Yuantao; LIU Xiujuan; WANG Wei; ZHANG Shuai; LIU Jia; FAN Hao

doi:10.13984/j.cnki.cn37-1141.2025.06.015

Abstract：The south coast of the Hangzhou Bay had significant ecological functions such as climate reg-ulation,carbon sequestration and sink enhancement,water purification and so on.However,the tem-poral and spatial distribution pattern of wetland vegetations had changed in recent years,especially the trend was more obvious after the construction of the 11th seawall in 2010,which had a certain impact on the ecological function of the wetland.Thus,our objective was to explore the change and influencing factors of the salt marsh wetland vegetations outside the 11th seawall after its construction.We princi-pally used six remote sensing images from 2010 to 2020 in this paper,we also created and used DSPI formula on the basis of NDVI index to improve the classification accuracy of vegetation,and ENVI ex-pert knowledge decision tree method was used for interpretation and analysis.The results implied that since the construction of the 11th seawall,the vegetation of the salt marsh outside the seawall had been replaced by the distribution pattern of Phragmites australis(high intertidal zone)-Spartina alterniflo-ra(middle and high intertidal zone)-Scirpus mariqueter(middle and low intertidal zone),which was originally dominated by Scirpus mariqueter.The comprehensive analysis showed that the major influ-encing factors of vegetation distribution pattern change in the study area were the environmental fac-tors,the biological factors and the human activities,in which the influencing factors would gradually change from environmental stress to biological competition with the increase of wetland elevation,while human activities would directly interfere with the natural succession of wetland vegetation.