Study On The Impacts Of Yellow River Estuary Sand Mouth Geomorphological Characteristics On Vegetation Distribution Pattern

The Yellow River Estuary is located in Dongying City,Shandong Province.It is a typical warm temperate semi-humid continental monsoon climate zone.It is one of the most important estuary wetland in China.It is also the fastest growing estuarine wetland in China and even the world.In the field of Ecology,it has great significance of studying the relationship between vegetation community and geomorphological development in the Yellow River Estuary as it can increase understanding of the relationship between vegetation community and non-zonal environmental factors.The results show that there is a clear correlation between vegetation community distribution and micro-geomorphology types.In this paper,two pairs of Sentinel-1A synthetic aperture radar(SAR)data in the two seasons,winter and summer are used to carry out the DEM construction test in the mouth of the Yellow River.The vegetation community distribution information and land cover patterns are extracted from images captured by Sentinel-2A,Landsat8 OLI in 2018 and Landsat5 TM in 2010.Different micro-geomorphic types are extracted from the DEM made in 2010.The relationship between vegetation communities and micro-geomorphology was discussed from the perspective of landscape and community.The main results show that:(1)The results of optical remote sensing image interpretation showed that the water area in the study area accounted for the larges t proportion with more than 40%.The followings are tidal flat or Tamarix chinensis-Suaeda heteropera community,Tamarix chinensis-Phragmites australis community,Suaeda heteropera,and Phragmites australis community.Artificial objects have the smallest proportion and are scattered.The vegetation community of the newly-developed wetland in the Yellow River Delta showed a concentric annular distribution trend along the river to the sea.From the Yellow River watercourse to the coast,the Phragmites australis community,Tamarix chinensis-Phragmites australis community,Tamarix chinensis-Suaeda heteropera community,Suaeda heteropera community and Spartina alterniflora Loisel community were distributed in order.(2)The yellow river estuary landform distribution can be qualitatively extracted from the DEM created from Sentinel-1A data.While affected by cloud and plant canopy,the elevation precision is low and it is difficult to meet the quantitative analysis requirements.(3)The landform types in the Yellow River Estuary are mainly tidal flats,extending along the coastline to inland for 7-8 km.Secondly,it is a river-forming highland formed by the sedimentation of the Yellow River,followed by depressions and ponds,which are distributed around the Yellow River channel and occupy a relatively small area.(4)Vegetation in the Yellow River Estuary is affected by the dual effects of water from ocean and land rivers.Plants such as Spartina alterniflora Loisel and Suaeda heteropera are affected by the ocean and are mostly distributed in the estuarine coastal area.Phragmites australis communities are greatly affected by the river,and are mostly distributed around the river banks and farther away from the coast.