Mapping and evaluation of landscape ecological status using geographic indices extracted from remote sensing imagery of the Pearl River Delta, China, between 1998 and 2008

This paper presents a method of mapping and monitoring ecological quality and environmental change using an ecological evaluation model (EEM), which is based on remote sensing data of the Pearl River Delta region in Guangdong, China. Five geographical indices were selected: Impervious Surface, Normalized Difference Vegetation Index, Land Surface Temperature, and Greenness and Brightness generated from the Tasseled Cap Transformation. These geographical indices are of ecological significance and they were used as variables to build the EEM through factor analysis. In addition, land use maps derived from remote sensing data were overlaid on these five index maps to analyze the effects of land use change on ecological status. Based on the EEM values, five levels of ecological zones were identified using a standarddeviation segmenting method. The results showed that the areas of the first and second levels decreased significantly, those of the third and fourth levels increased, and the area of the fifth level remained unchanged. It was established that the remote sensing method is practical for the analysis of ecological change, thus this work could be considered a case study for other ecological monitoring research.