Effects Of Strip Coal Mining On Landscape Pattern,Soil And Vegetation In The Typical Steppe Of Inner Mongolia

The exploitation of mineral resources brings enormous wealth to human being,but also triggered a series of environmental problems.Environmental and ecological problems of mining area has become a hot topic globally in the recent years.This study was conducted in a mining area of Baiyinhua in Inner Mongolia,field samples were collected,analyzed in the lab and data were analyzed with GIS and geostatistics.The objectives of the present study were to evaluate the effects of strip coal mining on landscape,soil and vegetation,and to access the dynamics and driving force of the landscape pattern in the mining area,and to determine the spatial differentiation characteristics of physical and chemical properties of the soil[soil pH,total salt content(SAL),total nitrogen(TotalN),organic matter(OM),available nitrogen(AN),available phosphorus(AP),available potassium(AK)],microelements(AZn,AFe,ACu,AMn),heavy metals(Cu,Cr,Mn,Pb)and vegetation community structure.Our study could provide references for species selection of vegetation restoration and substrate amendment in mining areas.The main findings are as follows:(1)There were no significant differences in landscape types and pattern indices at the beginning of mining.The indices of the patch count,patch density and edge density increased,the average patch area and average shape index decreased,the degree of landscape fragmentation and edge division significant increased with the scale of coal mining increased.In addition,the landscape uniformed and landscape heterogeneity enhanced with the scale of coal mining increased.The water landscape was affected by precipitation.The livestock counts and topography were primary reasons for landscape changes.(2)The content of heavy metals(Cu,Cr,Mn and Pb)in soils were impacted by the distance from the mining area,and they were negatively correlated to the distance.Four groups 0～0.5km,0.5～1.5km,2.0～5.0km and 5.5～8.0km were partitioned based on the degree of influence.The content of heavy metals among the groups differed significantly,and they also differed among different soil layers(0-1cm,10-20cm and 20-30cm)within 2km(p<0.05).(3)Vegetation composition of different disturbance treatments were significantly different,but it did not affect by the distance from the mining area in each disturbance treatment.The RDA analysis and correlation analysis between soil and vegetation indicators showed that heavy metal content was positively correlated to plant density and biomass of annual&biennials such as Setaria viridis,while negatively correlated to perennial bunchgrasses such as Stipa grandis.(4)The heavy disturbance areas were directly affected by the mining,which induced serious damage to the community and resumed succession.The community structure was not affected by the mining and impacted by heterogeneity of topography in other areas.