Faculty of Silviculture and Forest Engineering, Transilvania University of Brasov, Eroilor no, 29, Brașov, Romania.
Environ Monit Assess. 2021 Jan 5;193(1):30. doi: 10.1007/s10661-020-08834-w.
Surface mining represents the dominant driver of land coverage changes in the Jiu Valley mining area in Romania. Detecting and quantifying active mines and reclaimed areas are very important tasks given the effects of surface mining on the environment. In this paper, Landsat imagery for the years 1988, 1998, 2008, and 2017 was used to map the extent of surface mining and reclamation in the Jiu Valley mining area. The satellite images were classified using the Support Vector Machine (SVM) algorithm to map land cover classes, including mined areas, and post-classification comparison (PCC) technique to track changes through time. In order to identify and quantify active mines and reclaimed areas of mined areas, we used indices such as Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), and Modified Soil-Adjusted Vegetation Index-2 (MSAVI-2). For the entire area studied, during the period 1988-2017, the extent of surface mining was 6.5%, with peaks in the periods 1988-1998 and 1998-2008, namely, 205.2% and 4.0%, respectively, as a result of the extension of surface exploitation as distinct from that underground. Land cover conversion to mined areas was almost exclusively from agricultural, forest, and pasture. The results show that NDVI estimated the largest surfaces with active mines, reclaimed grassland, and reclaimed woodland, within the mined areas. SAVI and MSAVI-2 estimated larger surfaces classified as reclaimed forest. As a result of the expansion of surface mining areas, the landscape was considerably degraded through mining scars, landscape fragmentation, degradation, and pollution. However, during the past few years, reclamation activity has intensified in the affected areas through the occurrence of spontaneous vegetation, but also through forestation.
露天开采是罗马尼亚久伊河谷矿区土地覆盖变化的主要驱动因素。鉴于露天开采对环境的影响，检测和量化活跃矿区和复垦区是非常重要的任务。本文利用 1988 年、1998 年、2008 年和 2017 年的 Landsat 图像，对久伊河谷矿区的露天开采和复垦范围进行了制图。使用支持向量机（SVM）算法对卫星图像进行分类，以绘制土地覆盖类别图，包括矿区和后分类比较（PCC）技术，以跟踪时间变化。为了识别和量化活跃矿区和矿区复垦区，我们使用了归一化差异植被指数（NDVI）、土壤调整植被指数（SAVI）和改进土壤调整植被指数-2（MSAVI-2）等指数。在整个研究区域，1988 年至 2017 年期间，露天开采面积为 6.5%，1988 年至 1998 年和 1998 年至 2008 年期间分别达到峰值，增长率分别为 205.2%和 4.0%，这是由于露天开采的扩展而不是地下开采。土地覆盖向矿区的转化几乎完全来自农业、森林和牧场。结果表明，NDVI 估计了矿区内活跃矿区、复垦草地和复垦林地的最大面积。SAVI 和 MSAVI-2 估计了更大面积的复垦森林。由于露天开采面积的扩大，矿区景观因采矿伤疤、景观破碎化、退化和污染而严重退化。然而，在过去几年中，受影响地区的复垦活动通过自然植被的出现以及造林活动得到了加强。
