新疆戈壁矿区生态环境脆弱,极容易受到自然和人为因素的影响,其生态环境也逐渐被广 泛关注。 选取新疆五彩湾露天矿区为研究对象,利用 1990—2020 年 Landsat 影像,在遥感生态指数 IRSE基础上,引入煤尘指数、盐度指标、土地退化指数构建干旱煤矿生态指数(IACME),并运用 M-K 检验与 Sen 趋势分析法揭示研究区 IACME 时空演变特征与规律,评价干旱矿区的生态环境质量状 况,同时利用多元回归、神经网络、随机森林和支持向量机方法分别建立五彩湾矿区气候因素与 IACME 的关系模型,预测得到基于气候条件下的 I′ACME ,结合残差分析与双重差模型定量评估采矿活 动的影响。 结果表明:1 近 30 a 来研究区 IACME 均值为 0.28,总体上 IACME 呈下降趋势,由 1990 年的 0.30 下降到 2020 年的 0.22。 变化幅度方面,退化区面积占比为 62.63%,远高于改善区 28.3%,由 于采矿活动的影响,显著退化面积占比增加 12.96%,主要集中在以矿井为中心向外辐射区域,显著 改善面积占比下降 17.28%。 2 利用多元回归、神经网络、随机森林、支持向量机 4 类方法分别建 立气候因素与 IACME的关系模型,得到基于麻雀搜索算法的随机森林(SSA-RF)精度最高,验证集 R2 = 0.82、ERMS = 0.109,该模型在所使用的建模方法中可靠性更高,适用性较强;3 通过 SSA-RF 预 测基于气候条件的 I′ACME,气候影响下,研究区生态环境以较差(0.2~0.4)和中等(0.4~0.6)为主。 假设不存在采矿活动,研究区 2006—2020 年 I′ACME 在 0.26 ~ 0.59,I′ACME 平均值为 0.4,与同年份实际 的 IACME 空间分布相比,环境显著改善的区域明显增多,主要集中在研究区中部矿井所在区域。 4 利用残差定量分析得知研究区采矿活动对生态环境具有负向效应,平均残差 δ 为-0.116,通过 双重差分模型得出采矿对生态环境的定量影响为-0.112,进一步表明煤炭开采对生态环境存在负 面扰动,导致生态环境质量下降;2 种方法计算结果相近,表明 SSA-RF 与双重差分模型均可用于 定量分析煤炭开采的影响。 5采矿活动导致研究区生态环境退化占比为57.52%,改善占比为34.67%; 气候条件下导致生态环境退化占比为 42.28%,改善占比为 65.33%,采矿导致生态环境退化占比超过 50%,说明采矿活动是影响生态退化的重要原因之一。 综上所述,五彩湾矿区生态系统亟待恢复, 必要时应辅以人工干预,来推动五彩湾戈壁矿区整体的环境保护、生态系统修复与综合治理。

The ecological environment in Xinjiang Gobi open-pit mining area is fragile and easily affected by natural and man-made factors. Therefore,the ecological environment in Xinjiang mining area has been paid more attention. Taking Wucaiwan open-pit mining area in Xinjiang Uygur Autonomous Region as study area,coal dust index,salinity in- dex and land degradation index were introduced to construct arid coal mine ecological index (IACME) based on the remote sensing ecological index (IRSE) and Landsat images from 1990 to 2020. M-K test and Sen trend analysis were used to re- veal the spatial and temporal evolution of IACME in the study area,which evaluated the eco-environmental quality of ar- id mining area. Multiple regression,neural network,random forest and support vector machine methods were employed to establish the relationship between climate factors and IACME since mining and the prediction of IA′CME based on only climat- ic conditions was obtained. The influence of mining activity was quantitatively assessed by the residual analysis and difference-in-difference method. The results showed that:1 the average IACME of the study area was 0.28 during the past 30 years,indicating the quality of ecological environment was poor. The IACME of study area showed a decrea- sing trend from 1990 (0.30) to 2020 (0.22). The percentage of degraded area was 62.63%,which was much higher than that of improved area (28.3%). Due to the influence of mining activities,the percentage of significantly de- graded area increased by 12.96%,mainly located in the outward radiation area around the mine. The proportion of signif- icantly improved area decreased by 17.28%.2 The relationship model between climate factors and IACME was established using multiple regression,neural network,random forest and support vector machine methods in Wucaiwan mining area. The results indicated that the random forest of sparrow search algorithm (SSA-RF) had the highest precision in modeling with R2 being 0.82 and ERMS being 0.109 in verification set. SSA-RF had higher reliability and stronger applicability a- mong modeling methods used. 3 SSA-RF was adopted to predict Quantitative analysis I′ACME based on climatic conditions. The ecological environment of the study area was mainly in poor (0.2-0.4) and medium (0.4-0.6) levels. Assuming no mining activity,the average value of I′ACME in the study area ranged from 0.26 to 0.59 during 2006-2020, and the average value of IA′CME was about 0.4,which was significantly higher than IACME in the same year,mainly concen- trated in the middle of the study area where the mines was located.4 The residual analysis demonstrated that mining ac- tivities in the study area had a negative impact on the ecological environment with an average residual (δ) of -0.116. The results of difference-in-difference method showed that the negative value was -0.112,which further indicated that coal mining had a negative impact on the ecological environment,leading to a decline in the quality of the ecological environment. The results of these two methods were similar,indicating that SSA-RF and difference-in-difference method all can be used to quantitatively analyze the impact of coal mining. 5 The proportion of ecological environment degrada- tion and improvement caused by mining activities was 57.52% and 34.67%,respectively. While the proportion of ecologi- cal environment degradation and improvement caused by climatic conditions was 42.28% and 65.33%,respectively. The proportion of ecological environmental degradation caused by mining was more than 50%,indicating that mining activity was one of the important factors affecting ecological degradation. The ecological environment of Wucaiwan mining area needs to be restored urgently. Manual intervention should be supplemented to promote the environmental protection, ecosystem restoration and comprehensive management in the study area.