In this project, taking Yantai City for example, a coastal city lying in hill area, based on remote sensing, Geographical Information System (GIS), spatial modelling and landscape ecology analysis methods, the spatio-temporal variability characteristics of urban spatial expansion mode and its impact on regional landscape ecological risks were analyzed. Analysing comprehensively of different scenario simulation results and landscape ecological security pattern, the optimization mode of Yantai urban spatial expansion was established. The results were as follows,
(1) During 1974-2010, the area of arable land has been reducing continuously while the sustain increase in urban area was more and more visible, resulting in the dramatic change of the urban landscape patten index. The urban spatial expansion intensity was up to the peak value from 2004-2010 and the 8 km range between coastline and inland was the main expansion area. Resulting from spatial logistic regression, spatial differentiation analysis and social statistics multivariate analysis, the major driving factors of urban spatial expansion included the natural condition and coastal development activities related to coastal location, population growth, economic growth and policy management factors.
Resulting from the spatio-temporal variability characteristics of Yantai urban spatial expansion, accomparied by the leap-group expansion and low-density spread expansion, the strip-axis expansion was the leading orientation of Yantai urban growth.
(2) Resulting from the spatio-temporal variability characteristics of the landscape ecological risk under different historical poriods and urban spatial expansion scenarios, the area of higher ecological risk increased and the lower ecological risk decreased. The spatial distribution of landscape ecological risk was taken on circle-layered rank, and the risk value became smaller from the coastline to inland. Urbanization and the urban growth intensity index had a positive effect on the change of landscape ecological risk level. The larger the urban spatial expansion intensity was, the higher the lanscapte ecological risk was.
(3) To analyse and compare the future urban expansion patten and its potential regional landscape ecological risk, three urban spatial expansion scenarios were designed, which were historical trend scenario (Scenario HT), ecological protection scenario (Scenario EP) and coastal development scenario (Scenarion CD). The results showed that Scenario HT would have the fastest speed of urban spatial expansion, and correspongding the worst ecological risk and the highest-level space fragmentation degree. Scenario EP would have the lowest-level ecological risk but restrict the rate of urban spatial expansion to a certain extent. The ecological risk of Scenario CD was in the middle of these three scenarios. Its difference lied in that urban spatial expansion would promote along the coastline.
(4) The landscape ecological security pattern reducing “Source-Sink” ecological processe was designed. Combined with the urban spatial expansion scenario simulation results, the optimization mode and the management strategies of Yantai urban spatial expansion were established and advanced. These measures would provide decision- making support for other coastal cities development and integrated coastal zone management.
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