基于CA-Markov模型的乌江下游地区土地利用变化情景分析

以乌江下游的涪陵等6个区县为研究区,基于1995年、2005年、2015年的Landsat影像解译数据,综合运用GIS空间分析技术、CA-Markov模型和MCE模型,实现研究区土地利用时空格局模拟。结合情景分析方法,探讨在"快速城镇化情景"、"现状延续情景"和"生态保护情景"三种模式下研究区2020年、2035年、2050年的土地利用格局。结果表明:(1)在"快速城镇化情景"下,建设用地急剧扩张,35年间其面积增加了一倍,达到1 390.46km2,且主要来源为耕地,约占转出耕地面积的一半;林地增长十分缓慢,草地和未利用地持续减少,到2050年分别减少了186.58km~2和69.40km~2,未利用地减少了一半。(2)在"现状延续情景"下,建设用地增长仍然较快,2050年增加了347.92km~2,增幅达37.92%;耕地减幅有所下降,林地增加也比"快速城镇化情景"要快,但草地和未利用地仍在持续减少,35年间分别减少了25.9%和44.3%。(3)在"生态保护情景"下,林地、草地、未利用地等生态用地不断恢复和增加,到2050年,生态用地总面积占研究区的64%;建设用地无序扩张得到限制,到2050年其总面积为1 171.42km~2,比同期"快速城镇化情景"减少了219.04km~2;耕地虽有减少,但逐渐趋于平衡,始终保持在6 000km~2以上。因此,"生态保护情景"是研究区未来经济、社会和环境协调发展较为理想的模式。研究结果可为该地区土地规划、区域可持续发展提供科学参考。

Scenario Analysis of Land Use Change in the Lower Reaches of Wujiang River Based on CA-Markov Model

Based on interpretation data of Landsat images in 1995,2005 and 2015,we carried out the simulation on spatiotemporal patterns of land use by integrating GIS spatial analysis technique,CA-Markov model and MCE model,and taking the lower reaches of Wujiang River as the study area,such as Fuling district and so on.With the method of scenario analysis,the land use patterns of 2020,2035 and 2050 in the study area were discussed under such three scenarios as'rapid urbanization scenario','status quo continuation scenario'and 'ecological protection scenario'.The results show that:(1) in the rapid urbanization scenario,the construction land has expanded sharply,doubling its area in 35 years to 1 390.46 km2,and the main source is cultivated land,accounting for about half of the area of cultivated land transfer;forestland grows slowly,grassland and unused land continue to decline,which will be reduced by 186.58 km2 and 69.40 km2,respectively,by the year of 2050,the unused land reduced by half;(2) in the status quo continuation scenario,the growth of construction land is still growing rapidly,construction land will increase by 347.92 km2 in 2050,an increase rate is 37.92％;the decrease of cultivated land has damped down,and the increase of forest land is faster than that of rapid urbanization scenario,but the grassland and unused land continue to decrease,which will be reduced by 25.9％ and 44.3％ during 35 years;(3) in the ecological protection scenario,the ecological land,such as forestland,grassland,unused land and so on,continue to recover and increase,by the year of 2050,the total area of ecological land will account for 64％ of the study area;the construction land sprawl is limited,and its total area will be 1 171.42 km2 by the year of 2050,and will be reduced by 219.04 km2 compared with the same period rapid urbanization scenario;although the reduction of arable land,it gradually tends to balance,and always remains above 6 000 km2.Therefore,the ecological protection scenario is an ideal model for the coordinated development of economy,society and environment in the future.The results can provide scientific reference for land planning and regional sustainable development in this area.