草原区露天煤矿开发对草地植被NPP的影响研究

Impact of open-pit coal mining in grassland areas on grassland vegetation NPP

为了定量化评价草原区露天矿开发对草地生态系统影响,以伊敏露天煤矿为例,选择植被净初级生产力(NPP)指标,采用1985—2018年间21期卫星遥感数据进行长时间系列的NPP计算,分析露天矿开采对周边草地生态系统的影响程度及排土场生态恢复效果。结果表明,伊敏露天矿开发影响导致影响区草地NPP损失约10%~30%。随着恢复时间的增加,排土场植被不断向自然植被演替,NPP也不断增加并趋于稳定,稳定后的外排土场NPP已达到未受影响区历年NPP均值的90%左右,植被生产力接近自然植被生产力水平。但恢复时间较短的内排土场、北外排土场NPP均值仅达到未受影响区历年NPP均值的50%左右。露天矿生态重建与恢复是一个长期过程,外排土场的植被演替达到稳定状态需要20年以上,必须与露天开采活动同步推进,并长期坚持。

In order to quantitatively evaluate the impact of open-pit mining on grassland ecosystems,taking Yimin Open-pit Coal Mine as an example,the vegetation net primary productivity(NPP)index was selected,to calculate the long-term series of NPP using 21 satellite remote sensing data from 1985 to 2018,then quantitatively evaluate the impact of open-pit mining on the surrounding grassland ecosystem and the ecological restoration effect of the waste dump.The results indicate that,the open-pit mining has resulted in a NPP loss of approximately 10%to 30%.As the recovery time increases,the vegetation of the waste dump continues to evolve towards natural vegetation,and NPP also increases and tends to stabilize.After stabilization,the NPP of the external waste dump has reached about 90%of the average annual NPP of the unaffected area,and vegetation productivity is close to the level of natural vegetation productivity.However,the average NPP of the inner waste dump and the northern outer waste dump with shorter recovery time only reaches about 50%of the annual average NPP of the unaffected area.The ecological reconstruction and restoration of open-pit mines is a long-term process,and it takes more than 20 years for the vegetation succession of the external dump to stabilize.It must be promoted synchronously with open-pit mining activities and persisted in the long term.