内蒙古某铁矿尾矿库生态修复区的植被恢复效果

Effectiveness of vegetation recovery in an ecological restoration area around an iron tailings pond in Inner Mongolia

尾矿库生态修复可以在一定程度上阻隔库内污染物扩散,适宜植物种选择不仅有利于确保坝体地质安全,还是构建区域生态安全屏障的重要措施。本研究选取内蒙古某铁矿尾矿库的坝体边坡绿化、库外道路、人工湿地3个类型生态修复区,运用植物群落生态学的调查方法,分析与探讨了尾矿库外“边坡-道路-人工湿地”环境梯度下生态修复的适生植物种及物种多样性变化特征。结果表明:尾矿库生态修复区共发现植物31种,隶属13科30属,以菊科、豆科、禾本科和藜科为主,占总数的71.0%。边坡绿化区和库外道路区的草本优势种为狗尾草[Setaria viridis(L.)Beauv]、冰草[Agropyron cristatum(L.)Gaertn]、猪毛菜(Salsola collina Pall)、黄芪[Astragalus membranaceus(Fisch.)Bunge],共有灌木优势种为白刺(Nitraria tangutorum Bobr);人工湿地区的建群种为芦苇[Phragmites australis(Cav.)Trin.Ex Steud]。边坡绿化区物种多样性的Shannon-wiener指数(H值)和Pielou均匀度指数(J值)最高,分别为0.983和0.347,人工湿地区的H值和J值最低,分别为0.049和0.030;边坡-道路之间的相异性指数为0.647,道路-湿地之间的相异性指数为0.818,物种组成的替代速率前者大于后者。研究结果可以为相似类型的铁矿尾矿库生态修复的植物种选择和稳定群落构建提供参考。

To a certain extent,the ecological restoration of tailings ponds can prevent the seepage of pollution into reservoirs and is an im⁃portant measure for constructing a regional ecological security barrier.Three types of ecological restoration areas,including a sloped green area,road area beside the reservoir,and artificial wet area,were selected for an iron tailings pond in Inner Mongolia.A vegetation communi⁃ty survey was conducted,and the suitable plant species and species diversity variation in the ecological restoration process under the envi⁃ronmental gradient of“slope-road-artificial wetland”outside the tailings pond were investigated and analyzed.The results showed that a total of 31 species of plants were found in the ecological restoration area of the tailings pond,which belonged to 13 families and 30 genera;Compositae,Leguminosae,Gramineae,and Chenopodiaceae accounted for 71.0%of the total.In the sloped green area and road area beside the reservoir,the dominant herbaceous species were Setaria viridis(L.)Beauv,Agropyron cristatum(L.)Gaertn,Salsola collina Pall,and Astragalus membranaceus(Fisch.)Bunge,and the dominant shrub species was Nitraria tangutorum Bobr.Meanwhile,Phragmites australis(Cav.)Trin.Ex Steud was established as the group species in the artificial wet area.The Shannon-wiener index(H value)and Pielou in⁃dex(J value)of species diversity were the highest in the sloped green area with values of 0.983 and 0.347,respectively,and the lowest in the artificial wetland area with values of 0.049 and 0.030,respectively.The anisotropy index between the slope and road was 0.647,and that between the road and wetland was 0.818;The rate of substitution of species of the former was larger than that of the latter.The results can provide a reference for the selection of plant species and the construction of stable communities for the ecological restoration of similar iron tailings ponds.