Landscape Comprehensive Assessment Of Urban Green Space Based On The Ecological Suitability Theory

Urban green space is a kind of urban land which with the ground surface existing forms ofnatural and artificial vegetation. It's the unique living infrastructure of urban and play animportant role in maintenance of the urban ecological balance, improving the urban landscape,reflecting the city's character, it's the important symbol of urban spirit and culture. Ecologicalsuitability assessment of urban green space could coordinate the conflict between urbandevelopment and ecological environment protection and have important significance inevaluating the layout of urban green space scientifically, protecting the urban vegetation,planning the urban green space system and enhancing the function of urban ecosystem.This paper summarized numerous domestic and international research about the ecologicalsuitability, meanwhile combined with the situation of urban green space in Chang zhou andprobed the main methods of urban green space's ecological suitability assessment based on RSand GIS technology. The green space locations were identified in the study area frominterpretation of aerial photographs and field surveys, and a spatial attribute information databasewas constructed from each special graph. The spatial analyst model in ArcGIS9.3was used toanalyze the key factors which influence the green space suitability, such as land use, vegetationindex, population density, distance from road and water. This study used FR (frequency ratio)model and AHP (analytical hierarchy process) approaches to analysis urban green spaceecological suitability in Chang zhou. Correlation were examined among the two models throughthe Relative Operating Characteristic (ROC) and gave advance to the green space systemplanning of Chang zhou. The results showed that:(1)The author conducts visual interpretation for the1:10000aerial images of the built-uparea in Chang zhou city and extract the green space information of the built-up areas. Accordingto the patch areas, green space patch of Built-up areas is relatively fragmentized, the total numberof medium and small size green space patches accounts for98.25%of the total number of greenspace patches, but their total area only takes up72.17%of the total green space area. Accordingto the green space type, occupancy green space, other afflicted green space and manufacturedgreen space which accounts for87.81%of the total number of green space patches, but their totalareas only takes up81.84%of the total green space area; According to the composition ofvegetation, the number of trees and shrubs account for92.54%of the total number of the greenspace and their areas occupy83.24%of the total area of green space; meanwhile using theQUEST decision tree classification to extract5ground feature information from the TM imagesof2005, namely urban green space, farmland, construction area, water body and other sites. The total precision degree after classification is91.12%; the kappa coefficient is0.88. The greenspace patches that have relatively large areas in the study area mainly are located in the westernand southern areas of Wujin district, western areas of Xinbei district.(2)This study selected7factors include the industrial pollution distribution, waterdistribution, road distribution, land use, historic vestige and old trees, population density andvegetation index based on ecological principles and the impact to the layout of urban green space.The ROC area under the curve of AHP model (3groups weights) and FR model were:0.604,0.612,0.597and0.724. The AHP model's sensitivity was low and the FR model's sensitivity washigh relatively; The high suitable region of FR model mainly distributed in the west and north ofthe city, the unsuitable region mainly distributed in the center and the surrounding areas; the highsuitable and unsuitable region were accounts for13.14%and17.75%of the total arearespectively. Through validation and comparison of the two ecological suitability model, wecould effectively analyze the merit and fault of the models and provide a reference for theoptimization of the model.(3)This study analyzed the landscape pattern of the high and low suitable green patch ofthe FR model, the green patch of high suitable regional presented lower heterogeneity, lesshuman interference, more large patch, higher aggregation degree and lower fragmentation degree;the green patch of low suitable regional presented a serious anthropogenic interference, the lackof large patch, lower aggregation degree and higher fragmentation degree; this result validatedthe green space's situation of Chang zhou. This study analyzed the landscape pattern about thegreen patch of different suitability, combined with the current situation of urban green spaceobtained from the high-resolution remote sensing image, we can evaluate the layout of urbangreen space effectively and provide scientific advice for urban green space system planning.