近百年福州市区河流湿地景观演变分析

 以1950、1977和1996年海图为数据源,利用ArcGIS 10及FRAGSTATS 3.3,选取NP,CA,MPS,MSI,FD,LPI,FN,SHDI,SHEI及CONTAG等指标,对福州市区河流湿地南港(乌龙江)近百年来景观演变进行定量分析。依据岸线及0m等深线把河流湿地景观划分为河床、滩涂和岛屿沙洲三种类型。研究发现,研究区河流湿地面积减少,以河床减少最快,岛屿沙洲面积因并岸而微减后又增加,滩涂面积增加后略减少。总体景观异质性下降,河床从原来的连结为一体的基质转变为互相分割的廊道,其内部联系变弱,滩涂从原来被河床分割为零散的数十个斑块而连接成为面积较大联系较强的几个大斑块,成为研究区的基质,内部联系增强,岛屿沙洲经由分割合并而面积增加且形状日趋规整,对河床及滩涂的阻隔作用加大。

Landscape Pattern of the River Wetland in Fuzhou during the Last Century

The wetland is one of the most important ecosystems on earth. It plays an important role in the urban formation and its sustainable development. With the geographical expansion of cities, the wetland area is greatly reduced all over the world. The landscape pattern of the urban wetland experiences great changes at the same time. Fuzhou, the provincial capital of Fujian, the national level famous historical and cultural city, is located in southeast China, along the Minjiang estuary. The estuarine wetland around Fuzhou is seriously dwindled during the expansion of the city. A study of the spatio-temporal characteristics of its river wetland change may provide an important guideline for dealing with the conflict between the protection and the exploitation during the future urban development. Wulongjiang (Nangang), the south branch of Minjiang river, is mildly disturbed during the urbanization of Fuzhou. With three nautical charts supported by GIS technologies and Fragstats 3.3, the landscape pattern change of the river wetland of Wulongjiang in the last century is quantitatively studied in this paper. The river wetland is classified as the riverbed, the tidal flat and the island(shoal). The shorelines and 0m isobaths are taken as the demarcation lines in the classification. On the whole, the total area in the study is in a slightly declining state. The extent of the landscape heterogeneity is decreased. And various kinds of changes could be observed. For the riverbed, the internal connection is weakened; for the tidal flat, the internal connection is strengthened; and for the islands and shoals, their areas are increased and the shapes are simplified. The river wetland landscape pattern change is closely related to the human activity such as the split and merge of islands and shoals.