Characteristics of Plant Diversity and Heavy Metal Enrichment and Migration Under Different Ecological Restoration Modes in Abandoned Mining Areas

Abstract

In order to select plant materials suitable for the ecological restoration of abandoned mining land, ecological restoration experiments were set up in landfills. The effects of different ecological restoration measures on plant diversity and heavy metal enrichment and migration characteristics were studied. The results showed that under different ecological restoration measures, a total of eight families and 10 species of surviving plants appeared, most of which were herbs. The restoration effect of the arbor shrub and grass plots was the best; the plant coverage reached 100%, and the survival rate was over 69%. The diversity index of the plant community was as follows:arbor shrub grass > shrub grass > joe grass > grass. The dominant plants under different ecological restoration measures were Pinus elliottii, Ligustrum lucidum, Boehmeria nivea, Lagerstroemia indica, and Plantago asiatica. The contents of most heavy metals in plants were higher than the normal values. Among them, the enrichment and transfer coefficients of the leaf stems of P. elliottii and L. indica were close to or greater than 1, showing a strong ability of enrichment and transfer to Cd; these two plants belong to Cd-enrichment type plants. The roots of L. lucidum Ait and P. asiatica, which are root-hoarding plants, had a high retention rate of heavy metals. Boehmeria nivea was a heavy metal-avoidance plant with a low content of heavy metals in each part and had the ability to fix and repair potential soil heavy metal pollution. Considering the diversity of plants and the ability of plant enrichment and migration, the combination of trees, shrubs, and grasses was the best restoration mode. Pinus elliottii, L. indica, and P. asiatica can be the target plants for ecological restoration in the abandoned land of mining areas.