The Study On Landscape Pattern And Ecological Benefits Of Vegetation In Chongming Island

Vegetation includes all vegetable community in the region. And it's the most important part of the earth ecosystem. Vegetation landscape pattern plays a crucial role in the regional entironment, bio-diversity and etc. and it can affect the entironment, eco-security and the sustainable development of the social economy directly on larger scale.Chongming Island, which locates at the north of Shanghai, will be the vital social economic support to Shanghai in the future. Building forest ecosystem is the significant part in the ecological construction of Chongming Island and forest will be the most important ecosystem in Chongming Island. This article integrates the RS and GIS technique and combines the soft Fragstats 3.3 and Citygreen5.0. So that it could analyze the vegetation pattern and its ecological benefit quantificationally. The main results are as followings:(1) The research chooses several landscape indices which are sensitive to different grain as to study the grain size effect of indices, such as patch number(PN),patch density(PD),the average patch area(AREA-MN) and so on. There will get the scale effect curves by using Fragstats 3.3. Then the appropriate grain extent(12～15m) for the 1:50 000 TM image map of Chongming Island is determined by observing the domains of landscape indices which change with different cell size.(2) According to the remote sensing data, to quantificationally analyze the landscape pattern of Chongming Island and its division through the class-level index and landscape-level index.In the terms of the analysis of vegetation landscape types: Wetland and garden plot were the main landscape types in Chongming Island, and there were also some forest belt, attached green space and forestland.In the terms of general landscape pattern level, there were much more small areas in shadow and huge fragments that all most of them were certain complex in the investigative region. And the total vegetation area was 287Km~2 that was 18.1% of whole Chongming Island. The landscape had low dominance; in the point of the class-level, the maximum landscape area of Chongming was wetland which was 51.4% of whole landscape. The landscape area of forestland was the least that was only 1.84% of whole landscape. There were much more small areas and huge fragments that all of them were certain complex in the landscape type of garden plot, forest belt and attached green space. And they were spread in irregular form. The type of wetland and forestland were simple as well as regular that many of them were big areas with concentrated distribution.In the point of the class-level, the vegetation landscape of the function division had certain comparability to the whole vegetation pattern. The type of wetland and forestland had concentrated distribution with simple patch shape, big area and low fragment. There are much more small areas and huge fragments that all of them are complex in the landscape type of garden plot, forest belt and attached green space.In the terms of general landscape pattern level, the patches with big areas had high proportion that all most of them were certain complex in Changxing, Hengsha and the eastern Chongming. The landscape had low diversity,evenness and low fragment. They were just the same as that in west, north, south and middle Chongming, however, there was nothing but huge fragments which was just like that in south and middle area. In the middle and east area the landscape had high dominance compared with that in the south, that is there existed some patch types which had advantage against others.(3) The vegetation contributed greatly to sustain entironment in Chongming Island. The vegetation sequestrated carbon 8337 tons per year, the whole carbon storage reached 107.1 million tons which amount to 17726 million dollars; the vegetation removed air pollution about 2307844 pounds per year which amount to 547 million dollars; and the economic benefit was 1003 million dollars on the aspect of reducing rainstorm runoff. Its specific economic benefit was amount to 19276 million dollars.