1997—2017年南京沿江湿地资源的时空变化分析

Analysis of Spatio-temporal Changes of Wetland Resources along the Yangtze River in Nanjing from 1997 to 2017

湿地作为生态系统的重要组成部分,是连接水体与水体、水体与陆地之间的重要纽带。湿地资源的时空变化特征对于湿地资源的保护开发、城市建设规划有着重要的决策支持意义。该研究以南京长江沿岸3km缓冲区为对象,基于随机森林法,分别对1997、2009、2017年3期Landsat TM/OLI影像进行湿地资源分类。结果表明,1997—2017年南京沿江湿地总面积减少41.91km^2,其中水体总面积减少9.81km^2。湿地类型结构方面,天然湿地面积减少,人工湿地面积增多,主要表现为城市道路交通、港口建设等占用河湖湿地;退耕还湿、建立湿地公园、发展大棚农业等是稻田湿地转变为绿地的主要原因。因此,在未来城市规划建设中,要严格保护湿地资源,在保持湿地资源面积稳定的同时,更应注重优化湿地资源的生态结构。

As an important part of the ecosystem,wetlands are playing a significant role in linking water with water and land.The characteristics of spatio-temporal changes of wetland resources have important decision support significance for the protection and development of wetland resources and urban construction planning.In this paper,the three-stage Landsat TM/OLI images of 1997,2009,and 2017 were used to classify wetland resources based on the random forest method within the 3km buffer zone along the Yangtze River in Nanjing.The results show that,from 1997 to 2017,the total area of wetlands along the Yangtze River in Nanjing decreased by 41.91km2,of which the total area of water bodies decreased by 9.81km2.In terms of wetland type structure,the area of natural wetlands decreases and artificial wetlands increases,mainly manifested as the occupation of river and lake wetlands by urban road traffic and port construction;Returning farmland to wetland,establishing wetland parks,and developing green house agriculture are the main reasons for the conversion of paddy field wetlands to green spaces.In the future urban planning and construction,wetland resources should be strictly protected.While maintaining the area of wetland resources stable,more attention should be paid to optimizing the ecological structure of wetland resources.