赣南6县稀土矿区分布及其植被恢复的遥感动态监测

Remote Sensing Dynamic Monitoring on Rare Earth Mining Area and Its Vegetation Restoration of 6 Counties in Southern Jiangxi

稀土资源的开采在促进地方经济发展的同时对矿区生态环境带来了不良影响,为此有必要开展稀土矿区的分布动态及矿区植被恢复的监测。以江西省赣州市安远、龙南、定南、全南、信丰和寻乌6县为研究区,利用Google Earth平台的高分辨率影像,目视解译稀土矿分布范围,然后以多时相Landsat遥感数据来计算归一化植被指数和植被覆盖度,通过回溯法确定1990—2015年稀土矿开采范围的变化及矿区植被恢复状况。结果表明:稀土矿区总面积为58.23 km^2,其中定南和寻乌县的开采面积分别为18.23和16.27 km^2,分别占开采总面积的31.31%和27.94%;稀土矿开采的工艺以堆浸法为主,对地表植被破坏大;稀土开采在1990—2000年呈快速扩张趋势,在国家采取矿区管控措施后,稀土矿无序开采得到一定程度的遏制,2000—2005年开采面积减少,2010—2015年开采面积减少到9.21 km^2;以原地浸矿法为主开采稀土的龙南县,矿区植被恢复效果较好,其他各县的矿区植被恢复效果不明显。

The rare earth mining has promoted the local economic development but also has adverse effect to the ecological environment of mining area. Therefore,it is necessary to monitor the dynamic distribution and vegetation restoration of rare earth mining. Taking 6 counties of Anyuan,Longnan,Dingnan,Quannan,Xinfeng and Xunwu of Ganzhou City in Jiangxi Province as a studied area,using the high resolution images of Google Earth platform and visually interpreting the distribution range of rare earth mining. The paper determined the spectral vegetation index and vegetation coverage by using multi-temporal Landsat remote sensing data. The variation of mining scope and the conditions of vegetation restoration of the mining area from 1990 to 2015 were determined by using backtracking method. The outcomes show that a) the total area of rare earth mining is 58.23 km^2,of which,the mining areas of Dingnan and Xunwu are 18.23 km^2 and 16.27 km^2 and account for 31.31% and 27.94% of the total respectively; b) the mining technology of rare earth mainly is heap leaching method which is the most common method for rare earth mining and it will damage the vegetation coverage dramatically; c) the rare earth mining shows rapid expansion trend during 1990-2000 and the disorderly exploitation has been contained at a certain degree after taking management and control measures by the state. The mining area began to reduce in the period of 2000-2005 and was reduced to 9.21 km^2 during 2010-2015 and; d) the effect of vegetation coverage of mining area of Longnan County is better that mainly uses the method of in situ leaching and the effects of vegetation coverage of mining area of other counties are not satisfying.