Landscape Pattern Changes of Coastal Wetland in Nansha District of Guangzhou City in Recent 20 Years

In this paper, 6 types of coastal wetland (River, Dike-pond, Lake, Tidal flat, Swamp, Shallow sea waters) was classified precisely through supervised method and decision trees based on DEM, depth contour, high tide level, low tide level, vegetation coverage and soil map. Landscape metrics including area metrics, shape metric, aggregation metric and diversity metric were used to analysis the coastal wetland changes on class-level and landscape-level in 1995, 2001, 2005, 2009 and 2015. The results showed that the landscape pattern changed greatly in recent 20 years, especially since 2009, the coastal wetland area decreased sharply, distribution of coastal wetlands is becoming more and more uneven and the fragmentation is becoming more and more serious. Our study will provide scientific supports for coastal wetland planning and development policy making.