基于GIS的石漠化山区县域土地利用空间变化的生态风险测度

Assessment on Ecological Risk of Land Use Spatial Change at County Level in the Rocky Desertification Mountainous Area Based on GIS

为深入探寻石漠化山区土地利用动态变化的空间规律和土地生态环境的演变方向,利用晴隆县1988年、2000年、2016年3期遥感影像数据,在RS与GIS技术支持下运用土地利用动态变化空间分析模型、空间变化率指数、土地生态风险指数、土地利用变化综合生态风险度来测度土地利用变化对土地生态环境造成的风险。结果表明:(1)耕地、草地、未利用地三种用地类型间的剧烈转化,使研究区土地生态环境逐渐恶化;(2)人口上涨、城镇化进程加快、城乡工矿及居民用地极速扩张等对研究区的土地生态安全造成威胁;(3)近30年间土地生态风险程度呈先增大后减小趋势,但后16年间土地利用程度综合指数的增大、植被覆盖指数和多样性指数的减小,说明研究区存在石漠化程度加深、景观类型单一、生态稳定性差、土地生态风险概率加大等问题,晴隆县土地生态状况仍有恶化的趋势。土地利用变化的综合生态风险度与土地生态风险指数的测算结果相互印证,说明将上述方法用于评价石漠化山区县域土地利用变化的生态风险是可行的。

In order to explore the spatial evolution law of land use dynamic change and the evolution direction of land ecological environment in rocky desertification mountain area,the basic data were obtained from the 3 remote sensing images of Qinglong County in 1988,2000 and 2016.With the support of RS and GIS technology,the land ecological environment risks caused by land use change in the study area were calculated by using the spatial analysis model of land use dynamic change,spatial change rate index,land ecological risk index,comprehensive ecological risk levels of land use change.The results showed that with the drastic transformation following cultivated land,grassland and unused land,the regional land ecological environment gradually deteriorated;the rising population,acceleration of urbanization process,and urban industrial land rapid expansion were threatening the ecological security of the land in the study area;in recent 30 years,the degree of land ecological risk increased first and then decreased,but in the last 16 years,the increase of comprehensive index of land use degree,the decrease of vegetation coverage index and diversity index proved that there were some problems such as the rocky desertification degree,the single landscape type,the poor ecological stability and the increasing probability of land ecological risk,the land ecological condition in Qinglong County was still deteriorating.Mutual corroboration between the results of comprehensive ecological risk levels of land use and land ecological risk index certified that it is feasible to use these methods mentioned above to evaluate the ecological risk of land use change in counties of rocky desertification mountainous area.