| Rapid urbanization has led a series of ecological environment problems, such as environmental pollution, traffic congestion, densely populated and lack of urban greenspace, etc. Which directly affects the urban ecological environment and sustainable development. However, urban greenspace as the most important part of urban ecosystem, brings all kinds of ecological service function for human, and becomes a balance of urban ecological system and the contradiction of urbanization as well as the most important way to curb urban sprawl. So, quantitative research by multidisciplinary has become the hots for domestic and foreign ecological scholars. It has important application value for living environment improvement and protecting and planning of urban greenspace to researching space-time dynamic evolution and exploring the development law of urban greenspace pattern. The cities around Dianchi lake are core area to build into a regional international city for Kunming, which is western plateau city with unique natural geographical and cultural features, and also experienced a rapid expansion. There are great changes in landscape pattern and ecological environment. In this context, This paper slected three administrative units of the cities around Dianchi lake with different urbanization level (main metropolitan area, Chenggong district, Jinning county) as the research area, then used Landsat satellite remote sensing images of 1974,1992,2002, 2013 years as the basic source of information to extract all urban greenspaces information of the study area, and to explore the dynamic pattern and evolution of the urban greenspace landscape under different urbanization rate, and to take different scenarios simulation and prediction for future urban greenspace from the perspective of different planning policies, by using the methods of LCM model, landscape index and gradient analysis.The results showed a downward trend for urban greenspace at different spatial scales during 1974-2013 year. The farmland was quite obvious shrunk, while forest and urban greening area (forest and shrub/grass) performed a ascension. The urban greenspace and forest landscape showed positive growth and huge negative growth in 1974-2013 year. The built-up land showed a net positive growth, while shrub/grass and farmland showed a net negative growth. The farmland is the main contributor to convert to built-up land. The vegetation coverage showed a fall same as the trend of greenspace. The transfer trend mainly show that high green coverage changed to middle green coverage, high green coverage changed to low green coverage and middle green coverage changed to no green coverage. With the urban expansion, the patch area of urban greenspace is decreased, and the degree of fragmentation is more and more high, and has homogenization trend with a discrete state. The shape complexity was also corresponding higher. Connection degree is relatively decreased. In addition to connectivity, other index of forest showed a growth trend, which suggested that the importance of forest area has improved by the government, while the fragmentation degree is also increased. Analysis of concentric circles and multi-directions of landscape gradient of urban greenspace indicates that the index responds better to illustrate the affected by the concentric and diffirent directional of urban expansion. The change process of urban greenspace experienced the change process types of "aggregation"--"dissection"--"dissection".The relevant driving factors from three aspects of natural geographical factors, social economy and government policy were selected to predict the simulation of land use and greenspace in 2024 based on the existing city expansion rate, ecological constraints and greenspace system planning mode. The results showed that the urban greenspace based on ecological protection constraints is the best, the shrub/grassland and farmland will get the maximum protection, the second is the mode based on the greenspace system planning. Analysis of landscape change process of the predicted results found that urban greenspace still will experience the "dissection" process of which an increase in the number of patches but decrease in area.In this paper, We discussed the relevant relationship between the urban greenspace and the natural, social, economic as well as urbanization. And proposed some recommendations for the future development of urban greenspace in the study area. The research results have important theoretical and practical significance to the future of urban greenspace construction and city sustainable development, at the same time, it can provide scientific basis and reference case for urban greenspace reasearch and urban development in other similar areas with fast urbanization. |
