Evaluation of land ecological environment in Zhoushan Islands by remotely sensed impervious surfaces

摘要

Coastal islands are located in a transitional environment where land and ocean interact. During the past 20 years, large areas of the natural landscape of Zhoushan islands have been replaced by human features. There is limited research detailing the amount of impervious surface growth in the Zhoushan islands and trends in the land environment using remotely sensed technologies. The purpose of this paper is to assess the influences of anthropogenic activities on land ecological environment in Zhoushan islands based on remotely sensed impervious surfaces. First the impervious surfaces information of 1986, 1995 and 2006 were estimated using Landsat Thematic Mapper (TM) images, and then an integrated state indicator was built. The results reveal that imperious surfaces areas (ISA) of Zhoushan islands remarkably increased from 19.2 km~2 (2.73%) in 1986 to 29.5 km~2 (4.20%) in 1995, and to 58.2 km~2 (8.27%) in 2006. The average state value for the total area was 0.70, 0.65, and 0.55 respectively for 1986, 1995, and 2006. Of the surrounding islands, the Lujiazhi, Xiaogan, Panzhi, and Cezi suffered the most land disturbance intensity from human activities, followed by the Jintang, Xiushan, and Damao, and the Changbai and Changzhi had the lowest disturbance values. It indicates that the land ecological environment of Zhoushan islands was variously disturbed by growing human activities over time. Further, we found that the topography, island size, spatial location from Zhoushan Island and economic policy had an influence on change of impervious surfaces for each island.