晋北大型露天矿区景观生态风险时空异质性

Spatial-temporal heterogeneity of landscape ecological risk of large-scale open-pit mining area in north Shanxi

矿产资源开采对生态环境产生了剧烈扰动,加剧了矿区生态环境的风险性,严重威胁区域的可持续发展。从景观生态学角度将景观格局与生态风险相结合对矿区生态环境进行评估,从而揭示矿区景观生态风险的时空异质性,促进土地资源的可持续利用。以1990-2018年7期Landsat TM影像解译后的土地利用现状数据为数据源,构建景观生态风险指数,结合空间统计学及地统计学理论,探究1990-2018年平朔矿区景观生态风险的时空异质性。结果表明:1990-2018年平朔矿区景观生态风险的空间分布呈集聚分布模式,Moran’s I指数处于0.53~0.68,Z得分远高于检验阈值1.96,风险的空间集聚效应明显。1990-2018年平朔矿区的景观生态风险等级以中低、中、中高水平为主,占全区总面积的70%~90%,低风险区域主要分布于井坪镇以及白堂乡与向阳堡乡的大片林地,耕地是中等风险的主要分布区域,高风险区域逐渐向矿界内的矿业核心区收缩。1990-2018年平朔矿区景观生态风险空间异质性中的随机变异均小于空间自相关变异,由空间自相关部分引起的空间异质性占据主导地位。研究表明,在0.50 km×0.50 km的研究尺度下,1990—2018年平朔矿区景观生态风险具有很强的时空异质性,时间上呈现先增加后降低的趋势,空间相关性显著,空间分异特征明显。

The exploitation of mineral resources has severely disturbed the ecological environment,which intensifies environmental risk in the mining area and seriously threatens the regional sustainable development. From the perspective of landscape ecology,the ecological environment of the mining area could be evaluated by combining landscape pattern and ecological risk,which could reveal the spatial-temporal heterogeneity of landscape ecological risk in the mining area and promote the sustainable utilization of land resources. Based on the land use data of seven issues of Landsat TM images from 1990 to 2018,the landscape ecological risk index was constructed,and the spatial-temporal heterogeneity of landscape ecological risk in Pingshuo mining area from 1990 to 2018 was explored by combining spatial statistics and geostatistical theories. The results showed that the spatial distribution of landscape ecological risk in Pingshuo mining area from 1990 to2018 was concentrated. Moran’s I index ranged from 0.53 to 0.68. The Z score was much higher than the threshold of 1. 96. The spatial agglomeration effect of risk was obvious. The landscape ecological risk level of Pingshuo mining area was dominated by medium-low,medium,and medium-high,accounting for 70%-90% of the total area in the whole region. The low risk areas were mainly distributed in Jingping Town and the large woodland of Baitang Town and Xiangyangbao Town. Arable land was the main distribution areas of medium risk,while the high risk areas gradually shrank to the mining core areas within the mine boundary. The random variation in the spatial heterogeneity of landscape ecological risk in Pingshuo mining area was less than the spatial autocorrelation variation from 1990 to 2018. The spatial heterogeneity caused by the spatial autocorrelation was dominant. These results indicated that at the scale of 0. 50 km × 0. 50 km,landscape ecological risk in Pingshuo mining area had strong spatial-temporal heterogeneity from 1990 to 2018,with a temporal trend of increasing first and then decreasing,and with significant spatial correlation and obvious spatial differentiation characteristics.