| A coastal wetland is a transitional zone of the marine ecosystem and terrestrial ecosystem,which contains important material resources and natural resources.It plays an irreplaceable role in promoting the sustainable development of coastal society and economy,protecting biodiversity and maintaining the ecological environment of the earth.A coastal wetland is a zone which has a typical ecological "marginal effect",its development is influenced by land,sea and human activities,the environment of coastal wetlands is easily changed by external factors,which is a relatively fragile ecological environment.In recent years,with rapid development of the social economy in the coastal areas,the increasing impact of human activities and climate change on coastal wetlands has led serious reclamation and degradation of coastal wetlands.Therefore,carrying out the research about dynamic changes of coastal wetlands is very important significance for coastal wetland conservation and sustainable use.In this context considering the coastal wetland environment,obtaining high-precision dynamic monitoring data,revealing its dynamic and spatial evolution process under the background of climate change and human activities,The main driving factors analyzing is the premises of coastal wetland resource protection and management.In this study,we selected Quanzhou Bay in Fujian Province as research area.Regarding remote sensing data of Landsat TM/OLI in 1995,2005,and 2015 as source data,this study,firstly,adopts object-oriented classification method to access the data of Quanzhou Bay coastal wetland area,then,the change of each landscape type is quantitatively calculated by using the transfer matrix,to be continued,the quantitative studies of landscape patterns in the reserve area will be taken by utilizing the landscape index.Finally,the above studies are all integrated into analyzing driving forces which influence the change of the wetland in Quanzhou Bay.The results are as follows:(1)The results of extracting all types of wetland in Quanzhou Bay showed that the trend of total area was decreased from 1995 to 2000.Among them,from 1995 to 2005,the area decreased by 49.28km2 and from 2005 to 2015 the area decreased by 29.69 km2.The decreasing rate of wetland area between 2005?2015 was reduced because Quanzhou Bay estuary wetland protected area was established in 2003(2)Using land use transfer matrix and landscape index,quantitatively analyzed the change of coastal wetland landscape pattern in Quanzhou Bay from 1995 to 2015.The results showed that the highest conversion rate in Quanzhou Bay artificial wetland was a paddy field in 1995 to 2015,and the dynamic change rate of a natural wetland was mangrove.Shannon diversity index and Shannon evenness index were decreased and plaque spread index was increased,which reduce the diversity of wetland landscape.(3)By calculating and analyzing the centroids of study areas in 1995,2005 and 2015,the results showed that the various types of wetlands have different degrees of deviation in the past two decades.Among them,due to the high human disturbance,the centroids of the artificial human wetland is more complicated than the natural wetland,and the direction of migration was more complicated than a natural wetland.The shift direction of mangroves and herbs marsh were the same.They were shifted to the northeast of Luoyang River.(4)The driving force of the change of landscape pattern in this study area was analyzed from both natural and human factors.The natural factors consist of climate factors and invasive alien species,etc.The human-driven factors consist of population pressure,wetland protection,and economic factors,etc.The change of landscape pattern of Quanzhou Bay coastal land was a common factor between human factors and natural factors.Human driving force was the main factor of its change. |
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