Research On The Regional Ecological Landscape Patterns And Optimization Influenced By The Crossing River Channel Construction

Nowadays, China is in the process of accelerating the urbanization, resulting in massive expansion of the city.The situation inevitably changed the urban landscape pattern and disturbed urban ecological security with more ecological problems happening. Thus, keeping the balance between urban development and ecological security has important practical significance.With the development and wide application of RS and GIS technology, landscape ecology become more mature and perfective, and the dynamic process and optimization of the regional ecological landscape pattern have become one of the hotspots. So the papper takes Pukou for example, which promotes crossing river channel construction vigorously in recent years, using Erdas and Envi software of remote sensing to interpret remote sensing images in 1988 and in 1999 and in 2002 and in 2008. After that,using Fragstats3.3 to calculate landscape pattern index in order to analy the dynamic change of the ecological landscape pattern and ecosystem service value.Using the SLEUTH model to predict the dimension of construction land in 2020,in order to hunter for the dynamic changes of future landscape pattern and ecosystem service value.Using the gray multi-objective linear programming and the theory of landscape ecology to optimize the landscape quantity structure and spatial distribution in order to protect ecological safety. The main results include:(1) On the change of quantitive structure,the main patch types in the study area are farmland and vegetation in1988 and in 1999 and in 2002,whose area occunted for more than 60 pecent;Since 2002, with the development of urbanization process,the percentage of construction land increased corresponding with the reduction of the other types.The part of the reduction transformed into construction land,in the result the area of it became the second,just below the farmland.(2) On the change of ecological landscape pattern, landscape shape index in the southwest and northeast of the study area along the Changjing River and near the city was higher than other regions,the most obviouse towns were Yongning and Jiangpu and Xingdian and Qiaolin.The Shannon's Evenness Index and Shannon's Diversity Index in the northeast of study area was higher than in the southwest, in the meantime the towns along the river had higher result than others not along the river.Change of ecological landscape pattern abviousely led to the change of the ecosystem function, and the most significant variety of the ecosystem service values happened in the riverside regaion. Except the LaoShan forestry center and the town of Tangquan and Yongning, the others decreased during 1988-2008.(3) On the background of crossing river channel construction, urban expansion will occuer mainly in the towns along the Changjing River,re-added construction land is 4128.61 hectares with the percent of 14.76.The quantity structure and spatial pattern and the ecosystem service values had changed heterogeneity.Except consruction land, area of other landscape types decreased. Landscape shape index had notable decreaseing trend in Jiangpu, Pancheng,Dingshan,indicating that shape became simple and trimness.The Shannon's Evenness Index and Shannon's Diversity Index decreased mostly in the region along the river, and the difference of proportion among landscape types and the dominance increased, but heterogeneity decreased. The ecosystem service values had an decreased trend and the region along the riverside had the maxsium reduction.(4) Under the principle of maximizing overall efficiency, the paper had tried to optimize the quantitative structure of ecological landscape.Afer that, the farmland increased and construction land and water and other land area did not change and vegetation decreased.According to the basic landscape patterns"matric-corridor-patch", took the JiangPu street for example in the optimization of the ecological landscape spatial layout,through improving the agricultural and woodland matrix, reforming ecological corridor layout and protecting sensitive and ecological area and so on.On the precondition of regional urbanization being advanced rapidly, ensure the ecological safety.