Based on historical remotely sensed data covering the city of Shanghai between 1980 and 2018, we conducted quantitative studies on wetland landscape change and its driving mechanisms. In order to do ...so, we calculated landscape pattern indices by Fragstats 4.2.1 and analyzed the grey correlations between wetland landscape patterns and social, economic, and natural environments using grey relational analysis in data processing systems. The results showed that(1) the total area of wetlands, especially paddy fields, have been decreasing since the year 1980. By the year 2018, the wetland area has been reduced by 21.06×10~4 hm~2. The total area of wetland in Shanghai was 38.22×10~4 hm~2, and 85% of the area was the constructed wetland, the rest was the natural wetland. Constructed wetlands were mainly comprised by paddy fields, while natural wetlands were mainly river wetlands. The average areas of paddy fields and river patches showed fluctuated decreasing trends. The shape of river wetland patches was the most complex, and the total area of the river patches had been decreasing over the study period. The fractional dimensions index of the river patches fluctuated over the years but did not have a clear trend. The fractional dimension index of paddy fields fluctuated and had an increasing trend, and their landscape patterns had become more complex.(2) The degree of fragmentation of wetland landscapes intensified between 1980 and 2010, and the maximum patch index showed a fluctuated decreasing trend. Around the year 2010, the degree of fragmentation of wetland landscapes reversed, and the maximum patch index had become increasing. Between 1980 and 2015, the contagion index showed a fluctuated decreasing trend and the Shannon diversity index showed a fluctuated increasing trend. The year 2015 was the tipping point for the changes of the contagion index and the Shannon diversity index. The patch shape of reservoirs was relatively simple, and they had small inter-annual fluctuations and structural self-similarity.(3) The landscape patterns of wetlands were influenced by natural and human disturbances. Urbanization caused the decrease of constructed wetlands. The change of natural wetlands was mainly driven by the variations of temperature and precipitation. Natural factors usually had dominant influence on wetland landscape in large spatial and temporal scales. In the context of rapid economic development, human factors, such as national policy, had increasingly stronger influence on wetland landscape patterns in short temporal scale. In the future, the implementation of national policies on urban wetland conservation can help urban landscape patterns move toward better directions.
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