Land use/cover change in Yancheng coastal wetland

Yancheng coastal wetland is one of the biggest inter-tidal ecosystems in China,and plays important roles in supporting regional biodiversity and maintaining offshore water quality. Owing to the continuous exploitation in recent decades,this wetland has experienced significant changes. To reveal the dynamic changes of this wetland at landscape level,the land use/cover change (LUCC) since 1975 was investigated,based on the Landsat remote sensing data in 1975,1991,2002,and 2006. From 1975 to 2006,the natural wetland in Yancheng coastal wetland decreased by 56% (1.5×105 hm2),while fish pond and farmland increased by 892% (8.2×104 hm2) and 165% (5.9×104 hm2),respectively. Reclamation and fish pond exploitation were the main forms of LUCC,accounting for 75% of the total changed area,and natural succession and Spartina spp. invasion accounted for 11% and 7%,respectively. In the LUCC in Yancheng coastal wetland,there were three main transition processes,i.e.,intertidal mudflat → Suaeda salsa community → fish pond (farmland),intertidal mudflat → Suaeda salsa cummunity → Phragmites communis community → fish pond (farmland),and intertidal mudflat → Spartina anglica community → fish pond. The large scale shrinking of natural wetland would further reduce the survival space of wildlife and exacerbate the offshore water quality,and accordingly,reclamation controlling and wetland conservation should be strengthened.