The Changes of Wetland Network Pattern Associated with Water Quality in the Pearl River Delta, China

In the last 30 years, water environment and wetland patterns have been experiencing dramatic changes resulted from rapid urbanization, industrialization and population growth in the Pearl River Delta. To investigate the changes of wetland network pattern associated with water quality in this region, the structure indices and intercepting amount of pollutant of wetland network were calculated in this paper. The results showed that there were four type corridor wetland networks, inverted V, #, main river-way, man-made ditch according to river wetlands distribution characteristics. During the period of 19792009, river channel indices (Dr, alpha, beta, gamma) of all the four type networks showed a decreased tendency. For water quality parameter CODMn, NO?3-?N, NH?4+?N, TP, the inverted V type had the largest intercepted amount, the second is # type, then is main river-way type. The man-made ditch type also had higher intercepted amount. As to inverted V wetland network, amount of pollutants intercepted by per unit area wetland (Delta AW) was positive correlated with river corridor density, complexity, connectivity, linkage, and near index of paddy field and reservoir. There were significant positive correlations between Delta AW and corridor density, connectivity, linkage in the # wetland network; but significant negative correlation existed between Delta AW and paddy field density. Similar results also appeared in main river-way wetland network besides the significant positive correlation between Delta AW and near index of reservoir.