嘉峪关市城市化进程及景观格局动态变化

绿洲城市是中国干旱区人类活动最集中、人地关系最为敏感和复杂的代表性区域。本文以快速城市化绿洲城市——嘉峪关市为例,基于RS和GIS技术等从人口、经济、城市空间布局3个方面来分析嘉峪关市城市化水平,同时从斑块特征指数、景观多样性指数和景观空间构型指数等对绿洲城市景观格局进行定量分析。结果表明:1978—2009年间嘉峪关市城市化过程明显,城市人口比重从1978年的69.9%升至2009年的90.3%,城市建设用地年均扩张指数高达5.6%;嘉峪关市景观格局变化显著,景观多样性和异质性增强,耕地、林地和建设用地破碎度增加,草地和水域呈波动状态,未利用地破碎度减少;各斑块受干扰的程度增大,斑块几何形状更趋向规律性,基质成分减少;嘉峪关市城市化过程强烈影响着城市景观格局及其变化,人类活动对城市生态环境的影响作用逐渐增加。

Urbanization process and landscape change of Jiayuguan City, Gansu Province of Northwest China

Oasis city is the most sensitive and complicated area in arid regions of China,due to the fragile environmental system and intensive human activities.Based on the 1978-2009 remote sensing images and social statistical data,this paper analyzed the urbanization process and landscape change of Jiayuguan,a typical desert oasis city,aimed to reveal the effects of urbanization on the landscape pattern change of oasis city.In 1978-2009,Jiayuguan City had an evident urbanization process.The proportion of urban population was increased from 69.9% in 1978 to 90.3% in 2009,and the mean annual expansion index of urban area was up to 5.6%.In the meantime,the urban landscape pattern had an obvious change.The landscape diversity and heterogeneity increased,presenting in the increased fragmentation of arable land,forest land,and construction land,fluctuated grassland and water area,and decreased fragmentation of unused land,and the landscape patches were increasingly disturbed,their shapes becoming more regular,and matrix components being reduced.The urbanization process in Jiayuguan City strongly affected the urban landscape pattern and its change,and the impacts of human activities on the urban ecological environment had a gradual increase.