Ecosystem Health Research Of Zhejiang Province Coastal Zone Based On Remote Sensing Data

Coastal areas are located in the transitional zone between lands and seas, and greatly affected by the focused land-sea interactions. In recent years, due to global climate change and increasing anthropogenic activities, emphasis has been drawn to the ecosystem health in coastal areas, which requires detailed and systematic studies.For the purpose of further stimulating the protection and management in coastal ecosystems, concepts of ecosystem health are overviewed and indicators which control the health of coastal ecosystems are discussed in this thesis. Further, remote sensing data and information from published statistical yearbooks and bulletins are collected and extracted to quantitatively evaluate the ecosystem health along the Zhejiang coastal areas. The main contents of this thesis are:(1) The connotation and denotation of ecosystem health are reviewed and discussed, and the concept of coastal zone ecosystem health is presented. An assessment system, which is easily operated in practice, is established in this thesis to quantitatively reflect the status of ecosystem health along the Zhejiang coastal areas. The procedure of establishing the above evaluation system includes selecting of models and indicators, as well as choosing baseline values and indicators weights.(2) Using remote sensing data as the main information source, the geographic information system (GIS) is employed to analyze the impact of indicators which control the ecosystem health along the Zhejiang coastal areas in the past two decades. The coastal zone is divided into three fractions, i.e., the near-shore land subsystem, the coastline subsystem and the near-shore aquatic subsystem. The effects of different indicators to the ecosystem health are studied in these three subsystems. In near-shore land subsystem, indicators such as the annual average NDVI, vegetation area decrease, vegetation centroid movement and the slope of ten-year maximal annual NDVI, which are derived from SPOT/VEGETATION NDVI through the 10-day composited data from 1998 to 2007, are introduced to establish the vigor-organization-resilience evaluation system. In coastline subsystem, indicators such as the changed coastline, the increased land area and the fractal dimension values in three periods, which are all deduced from 1985 and 1995 TM,2005 ASTER, are incorporated. In aquatic subsystem, a series of indicators such as suspended particulate concentration, the chlorophyll concentration, the harmful algae bloom frequency, seawater transparency and temperature, which are retrieved from remote sensing data in 2005 and 2007, spatial distribution of sewage, ports and channels, as well as statistical materials are included, finally an aquatic ecosystem health evaluation system is established in the frame of anthropogenic pressure, physical, chemical and biological responses.(3) The intergrated assessment system is established based on Pressure-State-Response theoretical model, which is used to assess the ecosystem health along the Zhejiang coastal zones in recent years. Furthermore, the relevant determinant indicators are analyzed. The results show that from 2005 to 2007, the Zhejiang coastal zone ecosystem has been in an unhealthy state as a whole, but a trend of slight improvement was observed.According to the above three contents, the main contributions of this thesis about coastal zone ecosystem health are:(1) Based on studies worldwide, the assessment system is established to study the ecosystem health along the Zhejiang coastal zones, under the consideration of the natural environments and characters of the human activities in the study areas.(2) Based on remote sensing and GIS methods, a number of possible indicators affecting the ecosystem health in the coastal areas are identified and evaluated. The remote sensing retrieved indicators are involved in the assessment system, by which the spatial distribution of coastal ecosystem health status can be analyzed and shown by GIS.(3) The ecosystem health along the Zhejiang coastal areas can be dynamically evaluated by multi-year monitoring data, and the health changes can be analyzed in the coastal ecosystem health assessment system.