A landscape approach for wetland change detection (1979-2009) in the Pearl River Estuary

Based on landscape data produced from integrated Landsat MSS/TM/ETM+ images and spatial metrics, this paper presented a synthesis of wetland landscape changes in the Pearl River estuary from 1979 to 2009, and explored the spatio-temporal characteristics of wetland change. The classified images were used to generate maps of wetland degradation, and spatial metrics were calculated and analyzed across class level every five years. Results indicated that (1) the main wetland types in study area were shallow marine water and irrigated land. The total area of wetlands in the study region decreased by a quarter (4598km2), and the area of irrigated wetlands decreased more than that of other wetland types. (2) Artificial wetland had higher fragmentation than natural wetland, coming from the increasing patch density, and a decreasing of edge density. (3) Most of natural wetlands changed to artificial wetland, and artificial wetland changed to urban land and other land. More than 50% of urban land came from changed wetland. Urban development, as a main reason, caused the reverse succession of wetland landscape in the Pearl River Estuary.