| Accelerating urbanization in Hohhot has promoted the regional economic development on the one hand and brought great damage to the regional ecological environment on the other,thus generating problems of regional resources shortage and environment degeneration.Therefore,it is of great significance to protect the regional ecological security and achieve sustainable development of the city through studying the ecological and environmental problems caused by expansion of urban land in Hohhot.Against this backdrop,this paper employs " scenario simulation of urban land expansion-ecological risk effect-corresponding regulation strategy" as the main line of study and takes Hohhot urban area as an example.It draws on theories like landscape ecology,urban planning and other related and utilizes remote sensing,geograpfic information system and CLUE-S model to simulate the change of urban land use in different scenarios of Hohhot in 2025.On this basis,the risk assessment of the area for study is carried out.The aim of this study is to explore the impact of urban land expansion on ecological risks in different scenarios,and to provide regulation strategies for rational urban development.The results are as follows:(1)Based on the CLUE-S model,natural factors,socio-economic factors and distance factors were selected to simulate the land use change in Hohhot in 2010,and the Kappa index was used to verify the actual interpretation data in 2010.On this foundation,the land use change in the four scenarios of natural growth,grain conservation,ecological protection and land planning in the area for study was simulated respectively.The results showed that there were significant differences in land use pattern under different scenarios.(2)The coverage of urban land has expanded nearly three times over 24 years from 1990 to 2014,an increase by 32935.682 hm.The rate and intensity of urban land use are different in the four research periods,but the overall trend is increasing.The study shows the expansion intensity was the strongest in 2001-2010.(3)In 2025,the urban land in each scenario is increasing.Under scenario of natural expansion,urban land expanded the most,mainly in the east and the south of the city.Uunder ecological protection scenario,urban land use is smaller.with food protection scenarios,the layout of urban land mainly demonstrates expansion toward east and south,showing a complex city shape.In land planning scenario,the distribution of urban land is more concentrated.(4)In 2025,the overall ecological risk index of the study area is different,among which the ecological risk index is the lowest in the land planning scenario with only 0.1081 While the risk index amounts to 0.2252 in the grain conservation scenario.(5)The spatial distribution pattern of ecological risk in 2025 is quite different.In the natural growth scenario,the ecological risk is low and rather low,mainly distributing in the western part of the study area,the south of the Great Dahei River and the northeastern mountains.In the case of grain conservation,the proportion of high ecological-risk area is 66.39%,scattering throughout the northeast and south of the study area.In the ecological protection scenario,lower ecology-risk area accounts for 66.83%in the northern mountainous,eastern and southern regions except the Great Heihe River.Under the land planning scenario,ecological risk is even lower,taking up 79.38% of the study area.The high-ecological risk mainly distributes along the Great Heihe River.(6)The land planning scenario is the best urban development program from the perspective of the simulated land expansion and the ecological risk generated.In the future urban development,we should properly implement the policy of returning farmland to forest to ensure the regional ecologicalquality,secure basic farmland area to protect grain supply,rationally plan the urban expansion,and uphold ecological quality while promoting urban expansion. |
PDF Full Text Request