Study On Coastal Wetland Landscape Pattern Change And Coastline Change Of Donghai Island

Take the coastal wetland and coastline of Donghai Island in Zhanjiang,Guangdong Province as the research object,and RS,GIS technology as the main research methods,combined with field trips data and multitemporal remote sensing image data,obtaining the area data and the pattern index of the wetland landscape,as well as the fractal feature of the coastline,to analysis the changes of coastal wetland landscape pattern and coastline of Donghai Island.Based on the remote sensing images of the year 1991,2005 and 2014,gain the wetland landscape pattern of Donghai Island,and then calculate the area and dynamic degree.From 1991 to 2005 and 2005 to 2014,the landscape dynamic degree of artificial wetland changed from 1.45%to 2.65%,the landscape dynamic degree of natural wetland changed from 2.64%to-2.65%,the artificial wetland area increased and the natural wetland area decreased.During more than 20 years,the total area of the coastal wetland in Donghai Island increased,and the increased types were mainly the pond area,the artificial slash area and the bodies of water area.The fish farm area kept stable.Patch type level index and landscape level index can reflect the change trend of landscape pattern of the coastal wetland in Donghai Island.In general,the total number of coastal wetland landscape patches increased,which the number of ponds and bodies of water increased the most.The aggregation of wetland landscape became discreted,the diversity and uniformity became larger and towards the direction of crushing.The fractal dimension values of the coastline in Donghai Island had kept growing since 1991,indicating that the coastline became more complex.The north period of the island changed the most,especially from 2005 to 2014.The advanced to the sea of the coastline lead to the change of landscape pattern,making original beach,forest,bareland all into artificial slash.And the same time,the landscape pattern change of the coastal wetland lead to the change of the coastline.The main influence factor which changed the coastal wetland landscape and coastline was human activities,supplemented by natural factors.Human activities mainly included aquaculture,reclamation and building construction etc.,natural factors mainly included storm surges,sea level rise and the easy erosion of topography of the island etc..