Ecosystem Health Research Of Jiangsu Coastal Zone Based On Landscape Pattern

As the transition area between ocean and terrestrial ecosystem, coastal zone becomes one of the optimal regions for human production and life because of its abundant natural resources and superior location. However, in recent decades, the pressure on coastal zone has been gradually increasing due to the rapid economic development and population growth, which has resulted in some adverse factors influencing the stability of coastal zone and the sustainable development of regional economy, such as environment degradation, damaged ecosystem structure and function. Therefore, there is an important theoretical and realistic significance to research coastal ecosystem health and its evolution characteristics of driving force for the reasonable development and utilization of coastal resources, recovery of coastal ecosystem and regional sustainability.The coastal zone of Jiangsu Province was selected as the study area. Based on the remote sensing image data received from Landsat in 1995, 2002, 2009, 2013, we analyzed the change of landscape pattern and its relationship with human disturbance in study area with the aid of RS and GIS technologies and in line with the principle of landscape ecology. In addition, the system of ecosystem health assessment indicators was developed using “P-S-R” model at the landscape scale to analyze the temporal and spatial variation of ecosystem health. The major results are as follow:(1)The different landscape area in different time was found out by the image process with the combination method of supervision classification and visual interpretation. The results indicate that landscape types changed greatly. The area of water and bottomland were significantly reduced; the area of farmland was also in decline; while there was a completely inverse trend for the area of construction land and artificial pond. The fluctuation was found for forest land and grassland, which firstly decreased and then increased.(2)The landscape pattern index in landscape scale show that landscape pattern changed dramatically. Both landscape fragmentation and spatial heterogeneity were increased. Landscape shape became more complex.(3)Human disturbance index was calculated using HDI for the four periods. Human disturbance has varied to some degree over 19 years for 12 counties. There is a significant increase in five counties, which are Binhai, Sheyang, Rudong, Qidong and Haimen. The other counties also present slightly higher than before. It can be inferred that the human disturbance keeps increase in this area. Regarding to spatial changes, the human disturbance of the counties located in the central region are stronger than those in northern and southern regions. The correlation analysis between landscape index and human disturbance degree indicates that SHDI has the positive correlation with human disturbance,while AREA_MN, SHEI has the negative correlation. There are no strong correlations between LPI and human disturbance degree. It indicates that the strong human disturbance not only increase landscape fragmentation but also makes landscape diversity increase and landscape evenness decrease.(4)The system of ecosystem health evaluation index was established with the evaluation index selected by PSR model, and the index weight was determined by analytic hierarchy process and Entropy weight method. evaluation index was used to analyze the temporal and spatial variation of pressure, status and response factors of the coastal zone ecosystem. For the pressure part, Pressure factor value kept decreasing during 19 years, which suggests that pressure and stress of ecological system continues to increase, Northern region is under greater pressure than the central region and on the increase during study period. In terms of status part, the lower value of State factor in the central region illustrates that health condition of ecosystem was poor, while northern mountainous area and southern county(such as Qidong) were better. However, the State factor value of five sub-regions decreased Significantly. Regarding the response part, in 2002, the increasing of responses factors values were mainly attributed to establishment of conservation areas in Dafeng and Sheyang, but the values are lower in other period. The results demonstrate that there is a long way for human to protect and restore ecosystem.(5)Based on the system of ecosystem health evaluation index, synthetical index method was used to calculate comprehensive value of every sub-region and make an evaluation and comparison of the health condition. At the temporal scale, except that ecosystem health grade of Dafeng was better in 2002, other regions are good or worse grade in other stages. The synthetical index has been decreased since 2002, which indicated that the health condition of ecosystem continues to deteriorate. As for spatial distribution, regional area with worse grade accounts for 34%~45% of the total area and mainly distributes in the northern and the southern regions of coastal zone including Lianyungang, Ganyu, Guanyun, Nantong and Haimen. Regional area with good grade occupies 54%~66% of the total area and mainly distributes in the central regions including Xiangshui, Binhai, Sheuyang, Dafeng, Dongtai, Rudong and Qidong. In the region with greater population pressure and better economic situation, the ecosystem health condition was worse and worse due to the heavier stress, less protection and management. On the contrary,the regions with smaller population density and slower economic development, the situation is opposite. It can be concluded that human activity is the major drive force to cause the temporal and spatial differences of ecosystem health in the study area.