1977-2014年江苏中部滨海湿地演化与围垦空间演变趋势

通过野外实地调研与遥感影像解译相结合的方式,研究1977-2014年（1977、1984、2000、2007与2014年）江苏中部滩涂湿地演化与围垦空间演变的规律。结果表明,1977-2014年江苏中部滨海湿地射阳河口以南岸线段总体以淤长为主,但是也存在侵蚀的岸线段,总体淤长/侵蚀速度在±20 m/yr左右,最高值出现在东台和如东洋口港附近。研究区湿地围垦的速度远高于岸线淤长的速度,基本维持在50 m/yr以上。1977-2014年江苏滨海湿地的生态关键区面积出现了快速的退化趋势,特别是盐生植被空间的快速萎缩,主要出现在射阳南部和大丰市。调查发现研究区传统的湿地围垦开发演变模式是光滩→盐生植被→养殖水面→耕地→建设用地。但是现在由于新技术和新方法的应用,极大地缩短了围垦演变路径和周期,有助于围垦经济效益的提高。江苏滨海湿地围垦后土地开发利用强度呈较为明显的上升趋势。同时,江苏滨海湿地开发的热点空间在区域上主要集中于几个重要的港口及其腹地建制镇附近,但总体规模不大。

The changes and dynamics of coastal wetlands and reclamation areas in central Jiangsu from 1977 to 2014

Five remote sensing images (1977, 1984, 2000, 2007 and 2014) were obtained to study the spatial dynamics of coastal wetlands and reclamation area in central Jiangsu province. The results indicated that most of the coastal wetlands showed an accretion trend from the south of Sheyang estuary, while there still existed some erosion phenomena in the past 40 years. The mean rate of accretion/erosion of Jiangsu coastal wetlands was ±20 m per year, and the highest value was observed at Dongtai and Yangkou ports. Meanwhile, the reclamation rate was significantly higher than the accretion ones, and the former kept a level of 50 m per year. In addition, the key ecological areas of Jiangsu coastal wetlands reduced rapidly from 1977 to 2014, which can be found from the shrinkage of natural halophytic vegetation in the southern part of Sheyang County and the whole part of Dafeng County. It was found in field surveys that the evolution pattern of reclamation in coastal wetlands was in the order of bare flat → halophytic vegetation → aquaculture pond → cropland → built-up land. However, with the aid of new technology, the period of evolution pattern was shortened. Moreover, the development of coastal wetlands has been intensified due to reclamation activities. The hotspots of reclamation were presented at major ports and central towns.