土地利用变化的生态环境效应及其时空演变特征——以河西走廊为例

基于河西走廊地区1980—2020年的土地利用数据,运用ArcGIS空间分析方法,计算生态环境质量指数,对1980—2020年长时间序列土地利用类型变化及其生态环境质量的时空演变特征、变化频次、模式、圈层分布和空间聚集特征等进行分析。结果表明: 1980—2020年间,未利用地是研究区主要的土地利用类型,其中,建设用地、林地、草地和水域面积变化较多,土地利用类型之间转换明显。研究区生态环境质量恶化和改善的趋势同时发生,并在一定条件下相互抵消,生态环境质量指数呈先降后升的“U”型演变过程,整体生态环境质量波动变化不大。生态环境质量的空间集聚特征明显,总体分布特征为东南地区较高、西北地区较低,没有出现高频率、大变化;研究区东南象限的生态环境质量最差,西南和西北象限次之,东北象限的生态环境质量最好;生态环境质量类型转换持续下降区的面积大于持续上升区的面积,说明研究期间河西走廊的生态环境保护取得了一定成效。生态环境质量变化热点区域主要分布在河西走廊中部以及西南部,冷点区域主要分布在河西走廊西北部。

Eco-environmental effects and spatiotemporal evolution characteristics of land use change: A case study of Hexi Corridor,Northwest China.

Based on the land use data of Hexi Corridor region from 1980 to 2020, we calculated the ecological environment quality index and analyzed the spatial and temporal evolution characteristics, change frequency, patterns, circles of the long time series land use type changes and its ecological environment quality, using the spatial analysis method of ArcGIS. The results showed that unused land was the main land use type in the study area during 1980-2020. The area of construction land, forest land, grassland, and water changed more, and the transition among land use types was obvious. The trends of deterioration and improvement of ecological environment quality in the study area occurred simultaneously and offset each other under certain conditions. The ecological environment quality index evolved in a ‘U' shape, first decreasing and then increasing, with little change in overall ecological environment quality fluctuations. The spatial clustering of ecological quality was obvious, which was higher in the southeast and lower in the northwest, without high frequency and large change. The ecological quality in the southeast quadrant of the study area was the worst, followed by the southwest and northwest quadrants, while the ecological quality in the northeast quadrant was the best. The area of the continuously decline zone in ecological environment quality type conversion was larger than that of the continuously rising zone, indicating that ecological environmental protection in the Hexi Corridor had been effective during the study period. The hot spots of ecological quality change were mainly distributed in the central and southwestern part of the Hexi Corridor, and the cold spots were mainly distributed in the northwestern part.