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.