| In this paper, through interpretation, analysis and statistic to the three temporal TM remote sensing images in 1986, 1996 and 2006 with the collation and analysis of the field investigation and historical data, the landscape status of Yancheng costal wetland in Jiangsu Province were analyzed, the landscape pattern changes and their driving factors were researched, and also the habitat quality was assessed, based on the Red-crowned Crane monitoring records in Yancheng Nature Reserve and the changes of Yancheng costal wetland landscape. The results showed that:(1) Yancheng Coastal wetland landscape changed significantly in the period from 1986 to 2006. The characteristic of landscape changes in Yancheng coastal wetlands are shown as the natural wetlands declined substantially, such as the reed(Phragmites autralis) beaches, cogongrass (Imperata cylindrical varnajor) beaches and Suaeda glauca beaches, and the area with high intensive human activities increased significantly, such as the farmlands, aquaculture ponds and building sites. The loss area of natural wetlands from 1996 to 2006 was larger than the size of the loss from 1986 to 1996, and the loss of natural wetlands was significantly faster than the rate from 1986 to 1996. Among them, the area of spartina alterniflora beaches increase nearly 25 times from 1986 to 2006. The area of Suaeda glauca beaches dropped by 79.65 percent, the area of reed and cogongrass beaches dropped by 83.25 percent, the area of river wetlands dropped by 32.19 percent, and the bare flat beaches dropped by 44.08 percent. The area of bare flat beaches should decline less than 44.08 percent, for which was influenced by tide level in huge impact. The area of artificial wetlands, such as the aquaculture ponds, and farmlands increased gradually, and the area of salt fields changed little. The aquaculture ponds and farmlands were the main kinds of utilization mode in coastal area, the increasing rate of which were 169.50 percent and 106.09 percent respectively. In addition, the area of building sites increase by 445.75 percent.(2) According to the landscape pattern index in studying area during the three periods, the area of the single patch decreased, the complexity of it increased a little bit, the mean distance between the patches is reduced, the Interspersion and Juxtaposition Index changed little, the landscape diversity increased, and the evenness changed unnoticeable, which indicated that the disturbances in this area increased continued in the period, and the landscape fragmentation was increased with time.(3) The landscape of Yancheng Coastal wetlands in different regions changed significantly. The area of natural wetlands of the five coastal counties in Yancheng reduced continuously with different changed rate. There are less area of natural Wetlands in Xiangshui County and Binhai County and the area changes smaller also. The coastal wetland is widely distributed in Sheyang County, Dafeng County and Dongtai County. The wetland distributed in Dongtai County is the largest in this area, for the radial sand ridges area in the South Yellow Sea were put under Dongtai County in this study. The natural wetlands in Dafeng County reduced most and next to Dongtai County and Sheyang County. In the core, buffer and experimental zones of Yancheng Nature Reserve, the natural wetlands in core zones are still well preserved with the area of them reduced least, and the nature succession occupy the dominant position in the twenty years. During 1986-1996, the landscape change of buffer zone in Yancheng Nature Reserve relied mainly on the natural succession, and the natural wetlands reclamation of a large area became the main influence factor of landscape change during 1996-2006. The landscape change of experimental zone was shown as the natural wetlands were reduced sharply in the period from 1986 to 1996, and the losses of the natural wetlands were further aggravated during the period from 1996 to 2006. Among them the natural wetlands lost mostly in the 5th experimental zone during the twenty years, and the natural wetlands reclamation was the main influence factor of landscape change in the experimental zone.(4) The main factor of landscape change of Yancheng coastal wetlands was the natural wetlands reclamation, followed in descending order by natural succession of wetlands, land use changes and Spartina alterniflora invasion, and the artificial landscape naturalization only took quite small proportion. The reclamation intensity of natural wetlands in the period from 1996 to 2006 increased a little bit beyond the period from 1986 to 1996. The driving mechanism of landscape changes took human activity as the leading factor, which included reclamation policy of natural wetlands, technological progress, demographic changes and economic development. The landscape changes of natural driving factors included the costal wetland ecosystem succession, also included coastal erosion and siltation, spartina alterniflora invasion, and sea level changes, which held a subordinate position compared with the human activities.(5) Four major habitat factors for Red-Crowned Crane were identified by fieldwork, including disturbance, food, water regime and shelter in the study area,and these four habitat factors have indirect relationship with vegetation types, disturbance degree, food richness, water depth and shelter condition can reflect indirectly by vegetation types. The habitat factor changes were mainly reflected in the following: the increase of disturbance intensity and area, the abundance decline of foods, the appropriation decline of vegetation condition, the shrink of shallow water area and moist area, and the increase of deep water area and drying area. The habitat types with less disturbance, abundant foods and suitable vegetation cover decreased continuously, and the reduction rate of the patch numbers of different habitat types was smaller than it of the area of different habitat types, which showed that the habitat fragmentation degree strengthened gradually. The changes of landscape index showed that the habitat complexity increased and the landscape index change from 1996 to 2006 is faster than it from 1986 to 1996, which indicated that the disturbance is more serious. A habitat suitability index (HSI) model reflecting habitat factors and human impacts in landscape scale were built and five units were considered in the model, which were human disturbance, food richness, water regime in wetlands, vegetation shelter types and distance from road and residential area. According to the result of the habitat assessment, the field investigation and the historical records of the Red-Crown Crane investigation, the habitat types and distribution of the Red-Crowned Crane had changed greatly in the past twenty years: the area of suitable habitat reduced on a large area, the suitable habitat distributed continuously had changed into island-like distribution with significant habitat fragmentation, the distribution of the Red-Crowned Crane concentrated on the core zone of Yancheng Nature Reserve gradually, and the artificial wetlands has become a major habitat types of the Red-Crowned Crane.At last, according to the analysis of the landscape change of coastal wetlands in Yancheng and the result of habitat assessment of the Red-Crowned Crane, the protecting countermeasures of coastal wetlands and the habitats of the Red-Crowned Cranes in Yancheng were put forward.
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