荒漠草原金属矿区NDVI时空动态变化与生态质量评价

目的]采用遥感技术明确草原金属矿山开采的影响范围，综合评价矿区及影响区生态质量，为草原矿山及周边区域的生态修复与环境保护提供科学依据。方法]以地处生态脆弱区荒漠草原的金矿区为研究对象，基于长时间序列遥感数据分析研究区植被指数动态变化特征，采用遥感生态指数(RSEI)对研究区生态质量进行综合评价。结果]研究确定荒漠草原金矿开采影响区为矿区边界向外半径5 km范围内；矿山开采期间(2009—2021年)研究区NDVI值呈波动性增加，井工开采运行期矿区内NVDI年平均值比露天开采运行期提高了51.9%,露天开采对研究区植被影响更大；矿区及影响区遥感生态指数表现出先增加后减小随后趋于稳定的变化规律，整体以不显著增加为主；根据遥感生态指数的空间分布，矿区及影响区生态环境质量较差的区域主要为排土场及周边区域。结论]荒漠草原金矿开采对周边植被的影响主要集中在5 km范围内。采取边开采边治理的生态修复方式能使矿区及影响区的生态环境逐步得到改善。荒漠草原金矿生态建设过程中，应重点加强排土场及周边区域的生态修复与环境治理。

Vegetation Spatial and Temporal Dynamic Characteristics and Ecological Quality Assessment in Metal Mine Areas of Desert-Steppe

Objective] The impacts of a metal mine on the surrounding grassland were studied, and the ecological environment was evaluated using remote sensing technology as a significant aid to ecological restoration and environmental protection of mining areas. Methods] The study was conducted at a desert-steppe gold mine located in an ecologically fragile area. Spatial and temporal dynamics of normalized difference vegetation index (NDVI) in the mine area were analyzed based on long time series remote sensing data to conduct a comprehensive evaluation of the ecological quality of the study area using the remote sensing ecological index (RSEI). Results] The impacted area of desert-steppe gold mining was determined as the area with a radius of 5 km outward from the mine boundary. There was a fluctuating increase in NDVI values in the mine and impact areas that varied with the duration of mining in the steppe from 2009 to 2021. The annual average value of NVDI within the mine area during the underground mining operation period was 51.9% higher than during the open pit mining operation period. In addition, the impact of open pit mining on vegetation in the study area was higher compared with underground mining. The RSEI values in the mining area and the impacted area initially increased, then decreased, and then stabilized, resulting in an overall non-significant increase. The spatial distribution of RSEI indicated that the areas with poor ecological environmental quality in the mine and impact areas were mainly the waste dump and surrounding area. Conclusion] Gold mining influenced the surrounding desert grassland within a radius of 5 km from the mine. The ecological environment of the mine and the impacted area gradually improved through management efforts during mining. Ecological restoration and environmental management of the waste dump and the surrounding area should be strengthened during the process of mine ecological construction.