Change of Jingxin Wetland in the Lower Reaches of Tumen River Based on Corona and Spot-5 Images

Based on several Corona images in 1964 and Spot-5 images in 2004,combined with the utilization of GIS,RS and GPS technologies to extract and classify the information about Jingxin wetland in the lower reaches of Tumen River while done with the contrasting wetland classification maps of the research area of 2 years in this paper.By constructing the dynamic change model of this area,characteristics of the changes of the wetland landscape in this area have been studied from the perspectives of the area and fragmental change of various wetland types respectively and the causes for the changes also have been analyzed.The results indicated that all wetland types in the area have changed under the influences of climate change and human activities.The area of artificial wetland has increased by 16.923 km2 by the reasons of the establishment of Longshan Reservoir as well as the expansion of fishing ponds and hatchery ponds,whereas the natural wetlands have been destroyed severely,with an area reduction up to 17.33 km2.Apart from the drastic area changes,the fragmentation degree of wetland patches were also altered tremendously,which was shown in the sharp reduction of patch number of rivers and the highly fragmentation of marsh patches.The obvious drop of fractal dimension of Lacustrine and Riverine wetlands reflected both the weakening of the spatial similarity of these two and the huge disturbance by human activities.The study further found the lake areas in the area had increased during their transformation into artificial reservoirs partially in that the local residents expanded the lakes constantly for fishery and agricultural irrigation purposes.