Ecological Assessment Of Green Space In Shanghai Based On Land Use Dynamics

Rapid urbanization has brought up much negative effects to city structure and ecology&environment in Shanghai. Green space changes with the extension of built-up area. Since the1990s, many standards, policy and countermeasures have been introduced in Shanghai for better planning and construction of green space. With much efforts on improving green space for more than20years, how about ecological benefits of green space in Shanghai now? With spatial pattern of land-use change, what does green space take part in and how about the contribution to improving urban ecology&environment? So study on green space ecological assessment will be carried out devoting to solve these questions.(1) Spatial distribution of NDISI and NDVI from1997to2008, based on remote-sensing image band calculation, were carried out to indicate impervious surface and green space. Results show:â‘ as to built-up area, the distribution changes from "monocentric" to "multicentric". NDISI got a big decline from1997to2000in all while a little rise in central zone; NDISI of outer zone raise much from2000to2005and was more disperse in downtown area, especially in east of Huangpu River; to2008, NDISI raised continuously, especially in west direction;â‘¡as to green space, higher value located in outer area and NDVI declined expect the central zone. NDVI declined much from1997to2000, while got a rebound to2005and then declined to2008.(2) Study on land-use/land cover spatial pattern and coupling relationship between green space and impervious surface was carried out through geostatistical analysis and profile analysis. Results show:â‘ because of urban construction, NDISI shows nonrandom distribution indicating significant aggregation with high value in central zone and low value in outer area of Pudong District;â‘¡autocorrelation range of NDISI spatial variation decreases first and then increases with urbanization;â‘¢extension of impervious surface caused by human activities is main factor of LUCC; â‘£negative correlation exists between green space and impervious surface and the coefficient in the east-west direction is greater than north-south direction.(3) Based on CITYgreen Model and the TM image analysis of1987,2000,2004and2008, the comparative analysis in different spatial scales was done with basic statistics and the geo-statistical Analyst of ARCGIS. The results showed that:â‘ In large scale, from1987to2008, overall ecological benefit declined because of the encroachment of urban construction; however, from2000to2004, ecological benefit in some of the central districts had a brief rally due to the green-built measures conducted by Shanghai Municipal Government;â‘¡In middle scale, ecological benefit changes of different districts have different range and trend, such as the outer districts keep on higher level and change heavily, while the central were always in a low state. Although some measures about green space building have been brought up, the area in total is still decreasing;â‘¢In small scale, ecological benefit changed linearly from1987to2004while powerly from2004to2008; with surface fitting, the central area had a brief rally during the overall decline trend.Through data analysis, ecological benefits of green space in central zone is lower. And due to limited land resources, the urgent need to improve the overall ecological benefits by increasing the unit area level; negative effects of rapid urbanization, like high-strength development and construction, brought outer area loss of green space ecological benefits. Based on land-use dynamic feature, study on green space assessment and ecological benefit evolution in downtown Shanghai was carried out for better green space planning and construction and some scientific basis will be provided as well for green space planning of large cities like Shanghai.