Changes in landscape pattern of wetlands in the Pearl Rivers Estuary in the past two decades

The Pearl River Estuary, which is an important relay station and wintering area for waterfowls, is rich in a variety of wetlands resource. However, in recent decades, the industrialization and urbanization in the Pearl River Estuary had been developing rapidly, which changed the wetland landscape there dramatically. In this paper, based on remote sensing (RS) and geographic information system (GIS), several landscape pattern indices with obvious ecological significance were chosen to study changes in landscape pattern of wetlands in the Pearl River Estuary in the past two decades. Results showed that, over the past 20 years, the total area of wetlands in the Pearl River Estuary reduced by 700.62 hectares; the Landscape Diversity Index and Landscape Evenness Index continuously increased, suggesting that the dominance of shallow marine waters in the Pearl River Estuary had been weakened; the extent of the landscape fragmentation was serious, and the Contagion and the Aggregation Index dropped significantly, which suggested that the spatial distribution of wetland was scattered; the significant changes of landscape shape reflected the profound impact on wetland landscape of human activities.