Landscape Change Characteristics And Vegetation Restoration In Uranium Mining Area

The mining of mineral resources will cause certain damage and impact on the ecological environment,and the restoration and management of mining wasteland has become a common concern.Taking an leaching uranium mine in Erlianhot city as the research object,this thesis analyzes the characteristics of ecological landscape changes before and after the construction of the mining area based on remote sensing technology.Through the field experiments of different modes of vegetation restoration in the mining area,the growth characteristics of vegetation under different treatments are compared,and the suitable vegetation restoration mode for the mining area is selected which can be used as a reference for ecological restoration in different areas after decommissioning.The main results are as follows:1.The main land use type of the study area is grassland,accounting for more than83%of the total area.With the operation normalization and modelization of mining area,the influence of human factors on grassland ecosystem is weakened,and the NDVI inside the mining area and around the river increases significantly with the values from 0.21before the mining area construction to 0.25.A large number of bare land is restored to grassland,and 30.64 hm~2 of bare land is transformed into grassland after the construction of the mining area;The fragmentation and shape heterogeneity of the mining area decreases,the ecological environment shows obvious restoration characteristics,the habitat quality improved,and the habitat quality index increased by about 0.8.2.Considering the emergence days,emergence rate,biomass,plant number density,seedling height,coverage and other indicators of each plant species,the growth of each plant species is the best under the treatment of foreign soil,and is significantly higher than that of the control(P<0.05).Considering all kinds of indicators,Medicago sativa,Hedysarum mongolicum and Elymus dahuricus can be used as the candidate plants for vegetation restoration,Caragana microphylla and Caragana intermedia are native plants,and can also be used as the candidate plants for vegetation restoration according to the actual growth situation.3.According to the site conditions of different areas in the mining area,different vegetation restoration methods are selected:the topsoil backfill method can be used for vegetation restoration in evaporation pool area;In the production area and office area,after the buildings are removed and cleaned up,it can be directly covered with different mature soil to fix the surface soil layer for vegetation restoration;The lower part of the pumping and injection well is backfilled with waste rock and construction waste,which is naturally accumulated,and the upper part is sealed with reinforced concrete slab,which is covered with topsoil and then planted with vegetation;Shrubs and herbaceous seeds can be directly planted and sprayed around the pumping well.After the vegetation restoration of the abandoned land in the mining area,it is necessary to monitor and maintain on schedule,and adjust and improve the vegetation restoration scheme in time.