20世纪60年代以来6个时期长江三角洲滨海湿地变化及其驱动因素研究

Changes of Coastal Wetlands in the Yangtze River Delta for 6 Periods since 1960s and Their Driving Factors

以长江三角洲滨海湿地为研究区,利用长江三角洲地区1∶10万地形图数据、Landsat遥感影像数据和其它专题统计数据,采用人机交互的遥感解译方法,参照滨海湿地分类系统,对长江三角洲滨海湿地进行了分类;应用地理信息系统,分析研究区滨海湿地变化、围填海活动和景观格局变化。对比20世纪60年代、1980年、1990年、2000年、2010年和2015年6个时期的长江三角洲滨海湿地分布和面积发现,随着时间的推移,其总面积在减小,其中,天然湿地面积在减小,人工湿地面积在增加;研究区内的湿地类型转变主要是天然湿地转变为人工湿地,在天然湿地中,泥质海滩多转为淡水沼泽和盐水沼泽,在人工湿地中,水田主要变为城镇建设用地、工业用地和养殖用地,2000年之后,水田面积开始减少;影响长江三角洲滨海湿地变化的自然驱动因素主要为长江流域径流量、输沙量的变化,长江三角洲淤积量的增、减造成了长江三角洲滨海湿地演化,其人为驱动因素主要是围填海活动。

The change of the coastal wetlands in the Yangtze River Delta was investigated based on the1∶100 000 topographic map, Landsat remote sensing image and other thematic statistical data. The coastal wetlands in the Yangtze River Delta were classified using the method of the man-machine interactive interpretation based on the classification reference system for the coastal wetlands. The changes of the coastal wetlands, reclamation activities and landscape pattern were analyzed by GIS spatial analysis method. By analyzing the distribution situations and areas of the coastal wetlands in 1960 s, 1980, 1990, 2000, 2010 and 2015,the total area of the coastal wetlands was decreasing, in which the area of natural wetlands was decreasing and the area of constructed wetlands was increasing. The main internal transformation of the wetlands was that natural wetlands to constructed wetlands. In the natural wetlands, muddy beach was transferred to freshwater marsh and salty marsh. In constructed wetlands, the area of paddy fields began to decrease after year of 2000,which was mainly transferred into construction land, industrial land and aquiculture land; the main natural factors were runoff and sediment transport of the Yangtze River, which caused the siltation volume change. The most important factor of human activities was reclamation.