Landscape Changes Of The Wetland In Yueqing Bay Based On RS And GIS

Yueqing Bay is located at the southern coast of Zhejiang Province, which is a half-closed bay with rich wetland resources. Based on RS and GIS, the temporal and spatial landscape changes of the wetland in Yueqing Bay were studied by using two periods of landsat TM images, which were obtained in 1993 and 2003 .Because of the increasing anthropogenic interference, wetland landscape patterns and ecological environment in Yueqing Bay changed dramatically during the past decade. The total area of wetland landscape reduced substantially, but the area of construction land, belonging to non-wetland landscape, increased greatly. The whole landscape mean fractal dimension showed downward trend and all the landscape patches showed simplistic, low shape complexity and high self-similarity. Diversity index changed from 1.599 to 1.619,which illustrated the proportion of landscape types got more and more differently. The dominance index and evenness index were 0.703 and 0.695 respectively in 1993, which indicated the disparity among the proportion of various landscape types was quite large. But they reached 0.684 and 0.703 respectively in 2003, which means the dominant position of certain landscape types declined, and the whole landscape developed towards equalization.By extracting the landscape types of the two image data, a primitive conversion matrix and transferred rate matrix of the two period landscape were worked out with the aid of GIS9.2 software. Then, future tendency of the landscape was predicted based on Markov Model. At first, the practical data of 2003 was used to validate the model, showing that there were no significant statistical differences between the monitoring value of the landscape and the theoretic results of Marlkov process, which proved Markov Model is efficient and suitable for prediction of landscape changes of the wetland area. The result of prediction for Yueqing Bay indicated that if keeping the intensity of interference, wetlands will be dramatically decreasing, except the increasing of paddy field; woodland will decrease greatly and construction land will increase sharply.Meanwhile, the value of ecosystem services were estimated by using Costanza's and Xiegaodi's methods .The ecosystem service value of Yueqing Bay landscape types showed decreased trend in the past ten years. Except fish pond and farmland landscape increased, water area, marine, tidal flat and forest landscapes all decreased. Due to tidal flat and forest landscapes which had high ecosystem service value were reclaimed to farmland for the need of food , the total ecosystem service value of Yueqing Bay declined. In all of eight evaluating landscape types, the ecosystem service value of wetland landscape was up to 57.24%, which indicated wetland landscape ecosystem contributed the most to the whole ecosystem in ecosystem services value ratio. According to the results of the prediction, human disturbance is the most important influential factor that caused the temporal and spatial landscape changes of the wetland in Yueqing Bay.