Quantitative analysis of driving factors for wetland degradation based on hydrology balance

Abstract

Wetlands are among the most important ecosystems on Earth, which provide plenty of ecological services, and supporting the sustained development of the human being. However, with the development of our society and the change of natural conditions, lots of wetlands is degrading and disappearing. According to the conclusion from Millennium Ecosystem Assessment, the degradation speed of wetlands is faster than any other ecosystems. In order to protect wetlands, it is very important to monitoring degradation of wetland and analysis the driving factors resulting in degrading, then recognize the contribution of these factors by turns. Firstly, extracting exactly wetlands from satellite images is the key in this paper. In the hill region, with the help of spatial analyses function in geographical information system software and DEM simulation method, the simulated images of hill shade is gained according to the solar radiation conditions of remote sensing image, then the mixture of hill shade and wetlands in satellite images can be recognized, and influence of hill shade on wetland can be removed successfully. In the flat urban region, because there is the similar digital number scope of old residential areas and wetlands in urban region, the digital number is replaced with surface reflectance to extract urban wetland information,