基于遥感信息的二十年来上海市滩涂湿地时空动态分析

上海地区滩涂湿地是我国重要的湿地，含有丰富的生态价值。近年来，滩涂湿地受到了自然因素和人类活动的强烈影响，滩涂资源锐减，进一步影响了其生态系统的结构与功能。使用Landsat TM/ETM+遥感卫星数据，并结合大量的地面调查，对上海地区滩涂湿地近20余a的时空动态进行了探讨。结果显示：上海地区滩涂资源丰富，1 m等高线以上滩涂湿地面积33075 km2，主要分布在大陆边滩、长江口岛屿及江心沙洲等处；滩涂湿地淤涨快速，以年均100～300 m的速率不断向海延伸；滩涂湿地圈围强度较大，近20余a累积圈围滩涂65354 km2，严重影响滩涂资源及其生态环境。研究表明，人类活动是影响上海地区滩涂湿地变化的首要问题，为此，应遵循滩涂湿地的自然演变规律，同时加强协调管理，控制圈围，保护与合理利用滩涂资源

TWENTY YEAR DYNAMICS OF TIDAL MARSHES IN SHANGHAI BASED ON REMOTE SENSING DATA

Coastal tidal marshes in Shanghai,which are fragile and sensitive to environmental changes,play very important roles in maintaining biodiversity and estuarine ecosystem stability.However,over the last decades they have severely suffered from human activities such as land reclamation.Consequently,the structures and functions of the ecosystems are greatly threatened.In this study,we carried out field surveys as well as remote sensing analysis using Landsat TM/ETM+ data to demonstrate the development dynamics of the tidal marshes and reveal the impacts of diking on these areas in the past 20 years.The results showed:①the tidal marshes in Shanghai are distributed in the coast of the continent and the islands in the Yangtze River estuary,and the area has reached 330.75 km2;②the marshes have been expanding seaward in the past 20 years,and the coastline has been extending as the average annual rate of 100 ～ 300 m eastwards to the sea with the tidal development;③several large reclamation have taken place in the coast in Shanghai in the past 20 years,and the cumulate area of diked marshes is over 653.54 km2 from 1987.The continuous land reclamation have caused the great reduction of the area of wetland and the intertidal vegetation,which have caused great biodiversity loss and ecological degradation.Therefore,for the purpose of wetland conservation,the utilization of the tidal marshes such as land reclamation must follow the principle of dynamic protection,and ecosystem restoration is necessary in the tidal marshes in Shanghai.〖