Dynamic change of utilization and environmental pressure assessment of development in the sea area near Changxing island

This study to Changxing island sea area as the research area, and the high resolution remote sensing images of 2005 and 2015 are used as data sources, and the information of reclamation distribution, area and utilization type in Changxing island and its adjacent sea area is extracted and analyzed by means of GIS technology. The dynamic degree of utilization type of sea area, utilization transfer matrix of sea area, utilization structure information entropy of sea area and sea area development resource environmental pressure index are calculated. The comprehensive index of development and utilization intensity is used to analyze the dynamic changes of the development and utilization of the sea area near Changxing island from 2005 to 2015, so as to evaluate its development resource environment pressure intensity. The results show that: (1) in 2005－2015, the sea expansion rate of harbors near Changxing island was the fastest, with the dynamic attitude as high as 11.09%, followed by the unutilized expansion rate, while the sea area for salt industry showed a negative growth with a dynamic degree of −0.16%; (2) In the past 10 years, the main types of reclamation changed from sea area to reclamation, harbor and unused type; (3) During the study period, the information entropy increased from 0.96 in 2005 to 1.40 in 2015. The balance degree of sea area utilization structure was strengthened, and the structure of sea area utilization tended to be diversified and balanced; (4) In 2005 and 2015, 56.14% and 62.97% of the sea areas with moderate or higher environmental pressures on resources development in Changxing island, 80.7% of the area with the change of the environmental pressure index greater than zero, and the intensity of the environmental pressure is gradually increasing