黔中喀斯特山地城市土地利用/覆被变化及其生态效应评价——以贵阳市花溪区为例

快速城市化发展对脆弱喀斯特山地城市生态环境造成严重威胁，系统监测评价城市土地利用/覆被格局变化及其生态效应，协调生态保护与城市发展的关系是新时期喀斯特山地城市生态文明示范城市建设的重要命题。以贵阳市花溪区为对象，以2013年和2018年Landsat ETM/OLI遥感影像为主要数据源，运用遥感和GIS技术，采用遥感生态指数（Remote Sensing Ecological Index，RSEI）模型，在系统分析研究区土地利用/覆被类型和生态环境质量时空动态变化的基础上，剖析土地利用/覆被变化的生态效应。结果表明：（1）2013-2018年花溪区土地利用/覆被格局发生明显变化，形成以林地、建设用地和耕地3种类型占优的格局态势，以耕地的大量减少（减少约15353.37 hm²）且90%转为建设用地或林地、灌木地为主要特征，并伴有局部林地退化（约2683.80 hm²）的现象；（2）5年间，花溪区生态环境质量呈下降趋势，RSEI从2013年的0.622下降到2018年的0.499，下降约20%，反映植被覆盖度和不透水建设用地的绿度指标和干度指标对花溪区生态环境质量的贡献最大；（3）土地利用/覆被与生态环境质量的分布和变化在空间上基本吻合；林地面积或林地与灌木地面积的增减对生态环境质量的变化具有显著影响，林地或林地与灌木地面积增加10%，可使生态质量好转面积增加约15%-20%，或减少生态质量恶化面积约4%；而林地的退化面积增加10%，可导致生态质量恶化面积增加约14%。研究可为喀斯特山地城市国土空间格局优化、城市生态环境改善、生态文明城市建设提供科学依据。

Assessment of land use/cover changes and its ecological effect in karst mountainous cities in central Guizhou Province: Taking Huaxi District of Guiyang City as a case

Rapid urbanization poses a serious threat to the ecological environment in the fragile karst mountainous cities. Systematic monitoring and evaluation of urban land use/cover pattern changes and its ecological effects, and coordination between ecological protection and urban development are important propositions for the construction of demonstration cities of ecological civilization in karst mountainous cities. Taking Huaxi District of Guiyang City as the object, Landsat ETM/OLI remote sensing images in 2013 and 2018 were the main data source. Based on remote sensing and GIS technology and using remote sensing ecological index (RSEI) model, the land use/cover types and eco-environment quality were systematically analyzed, and the ecological effects of land use/cover change were accessed. The results show that:(1) The land use/cover pattern of Huaxi District has changed significantly from 2013 to 2018. The cultivated land was decreased nearly 15353.37 hm², and 90% of the transferred cultivated land were converted to construction land or woodland and/or shrubbery land, accompanied by partial forest land degradation (2683.80 hm²), which formed a pattern dominated by woodland, construction land and cultivated land types. (2) In the past five years, the ecological environment quality in Huaxi District showed a downward trend with RSEI value decreased from 0.622 in 2013 to 0.499 in 2018. The greenness index and dryness index were the most contribution factors to the quality of ecological environment in Huaxi District. (3) The spatial distribution and change of land use/cover and ecological environment quality were coincided with each other. The increase or decrease of forest land or forest land and shrub land area had the significant impact on the change of ecological environment quality. The 10% increase of forest land or forest land+shrub land area could increase the area of ecological quality improvement by 15%-20%, or reduce the area of ecological quality deterioration by 4%. However, the forest land degradation area increased by 10% might lead to the ecological quality deterioration area increased by about 14%. The research can provide scientific basis for the optimization of land use space pattern, the improvement of urban ecological environment, and the construction of ecologically civilized cities in karst mountainous cities.