人类围垦活动对上海崇明东滩滩涂发育的影响

由于长江口泥沙的淤积，使上海崇明东滩成为一个不断淤涨的土地资源。近50年来，崇明岛共进行了多次大规模的围垦。此项研究以近20年来的Landsat TM和ETM遥感卫星数据为主要数据源，并结合实地景观调查，对不同时期的人类围垦面积和滩涂发育面积之间的关系进行探讨。结果显示，滩涂湿地的面积在逐年变小：从1987年的19705.09 hm2 锐减到2002年的4773.08hm2，减少了75.78%；并且滩涂湿地面积的年减少率为995.47 hm2/a，比年围垦率的729.08hm2/a增加了36.54%。过度围垦后，滩面宽度变窄，自然植被破坏，影响自然促淤，淤涨速率明显减慢。随着滩涂围垦的加剧、未来海平面的上升和河流泥沙大量减少，将会导致潮滩植被进一步破坏。随着崇明东滩每年向外延伸，滩涂湿地也将会发生演替。因此，充分运用“3S技术”，探讨湿地发育和形成的机理，指导科学围垦和土地利用规划，是非常迫切也非常实用的方法。同时，还可以通过动态保护管理，进一步对围垦在经济、生态和环境上的得失作出正确的评价。

The Effect of Reclamation on Mud Flat Development in Chongming Island, Shanghai

Due to the deposition of silts at the Yangtze River estuary, the eastern beach of Chongming Island in Shanghai continues to expand. Several large-scale reclamations have taken place on the Chongming Island in the last 50 years. The aim of this study was to investigate the relationship between reclamation size and mud flat development size during different period of time. It was achieved by a combination of field surveys and the use of Landsat TM and ETM remote sensing satellite data of the past 20 years as the key data source. The result showed that the size of mud flat wetland decreased rapidly: from 19705.09 hm2 in 1987 to 4773.08hm2 in 2002, a 75.78% drop in 15 years. In addition, the annual reduction rate of the mud flat wetland size was 995.47 hm2/a, which was 36.54% more than the annual reclamation rate, 729.08hm2/a. The decrease in the width of beach, the destruction of natural vegetation and the decreasing of silt deposition rate are three negative effect of excessive reclamation. The destruction of beach vegetation will be more aggravated with further mud flat reclamation, the rise of sea level and a drop of silts. Biological succession at the mudflat wetland occurs as the eastern beach of Chongming extends further each year. Therefore, it is important to use " 3S technology " to investigate and monitor the mechanism behind the formation and development of wetland. The same technology should also be used in managing controlled reclamation and the plan in land use. Moreover, the effect of reclamation on the local economy, ecology and environment can be evaluated correctly by a dynamic management plan.