近20年来长江三角洲海岸带典型区土地利用变化与生态环境效应研究

【研究目的】近20年来，长江三角洲海岸带地区土地类型结构发生显著转化，海岸带开发与保护的矛盾凸显。本文旨在开展长江三角洲海岸带典型区土地利用变化与生态环境效应研究，为海岸带地区的土地资源可持续利用、海岸带环境保护提供科学依据。【研究方法】利用美国Landsat卫星系列遥感影像和中国资源卫星系列遥感影像，采用自动监督分类并结合目视解译，获取了研究区1995—2015年共5期土地利用分类数据，分析土地利用变化特征和趋势，探讨长江三角洲海岸带典型区城镇发展、围填海时空变化及生态环境效应。【研究结果】长江三角洲海岸带典型区（南通、上海、嘉兴、宁波和舟山）1995年至2015年，土地利用变化明显，耕地大幅度减少，比例从1995年的68.8%降为2015年的55.7%；城镇建设用地迅速扩张，年平均增加192.8 km²。【结论】在快速城市化过程中，人口、单位面积能源消耗等快速增加，环境问题凸显，大量的耕地转为建设用地，围填海使滨海湿地面积快速减小和消失，导致CO₂和污染物释放与吸收严重失衡，海洋环境受流域和沿海城镇化建设的影响明显，长江口及邻近海域近20年来赤潮频发，研究区陆域和海洋环境压力增加。创新点：选取长江三角洲海岸带典型区，首次以1995—2015年5期序列遥感影像数据为基础，采用空间叠加分析方法，着重分析了建设用地和围填海区域的时空演化特征；以人类活动为主线，综合多种海洋环境指标，分析快速城市化进程中，建设用地和围填海导致的生态环境效应。

Land use change and ecosystem effect in typical coastal zone of Yangtze River Delta in the last 20 years

This paper is the result of the environmental and ecological survey engineering.Objective]In the past 20 years, the land type distribution in coastal areas of the Yangtze River Delta has been significantly transformed, highlighting conflicts between coastal zone development and protection.This study examines land use changes and eco-environmental effects in coastal areas of the Yangtze River Delta and seeks to provide a scientific basis for the sustainable use of land resources and environmental protection in the coastal areas.Methods]Automatic supervised classification combined with visual interpretation of remotely sensed images from the Landsat satellite series of the United States and the resource satellite series of China was used to obtain land use classification data for the study area over five periods between 1995 and 2015. The data were analysed to determine the characteristics and trends in land use changes and explore spatial and temporal changes in urban development, reclamation, and eco-environmental effects in typical coastal areas of the Yangtze River Delta.Results]From 1995 to 2015, the typical areas (Nantong, Shanghai, Jiaxing, Ningbo, and Zhoushan) experienced significant changes in land use, with a notable decrease in arable land from 68.8% in 1995 to 55.7% in 2015, whereas urban construction land expanded rapidly, with an average annual increase of 192.8 km².Conclusions]With rapid urbanisation, the population and energy consumption per unit area increased rapidly, environmental concerns became pronounced, a large area of arable land was converted to construction land, and reclamation caused a rapid decline in coastal wetland areas, resulting in high CO₂ and a severe imbalance between the release and absorption of pollutants. The marine environment has been significantly affected by the construction of watersheds and coastal towns, and red tides have occurred frequently in the Yangtze River estuary and adjacent waters in the past 20 years, thereby increasing pressure on the land and marine environment in the study area.Highlights: (1) This study examined typical coastal areas of the Yangtze River Delta and used remotely sensed image data of five periods between 1995 and 2015 and performed spatial overlay analysis to identify spatial and temporal evolution characteristics of construction land and reclamation areas. (2) With a focus on human activities, we used a combination of marine environmental indicators to analyse the eco-environmental effects of construction land and reclamation in the course of rapid urbanisation.