Spatio-temporal Evolution Characteristics Of Land Use Change And Ecological Impact In A Large Opencast Coal Mine Area

Land use change is a basic parameter to quantify the changes in the natural environment and human activity,which has become one of the focuses of global environmental change research.Large opencast coal mines are mainly located in the ecologically fragile area in the northwestern in China,and opencast coal mining has severely destroyed the vegetation in the mining areas,changed the physical properties of the soil,causing land degradation,decrease in biodiversity and other ecological environment problems.At present,there is insufficient research on spatio-temporal evolution characteristics of land use in large opencast coal mine areas,and little attention is paid to ecological response changes.The study takes Pingshuo opencast coal mining area as an example to study the land use change and ecological response in large-scale opencast coal mine areas based on complex networks and the theory of landscape ecology,and systematically reveals the spatio-temporal evolution mechanism and ecological changes of land use in mining areas.On this basis,the land use in the opencast mining area is optimized.It is of great significance to the ecological environment protection and efficient and sustainable land use in coal mining areas.The main results are as follows:(1)From 1986 to 2015,with the dual influence of coal mining and high-speed urbanization,the area of agricultural land decreased by 10171.17hm~2.Agricultural land was the main output land type,and construction land and industrial and mining area land were the main input land types.In the process of land use in coal mining areas,the key land use types varied in different periods.Large-scale opencast mining activities severely affect land use change,and the overall stability of the land-use system was poor.(2)The vegetation fractional coverage of the whole coal mine area increased from 1992 to2015,and it was the lowest in 2009.The vegetation fractional coverage of four dumps in the study area were the lowest at the initial reclamation time,and increased with increasing reclamation time.The global Moran’s Index in the study area increased,and the local Moran’s Index showed that the vegetation fractional coverage of the whole stage was mainly high-high clustering and low-low clustering in 2015.(3)The study area was in the period of land use development and socio-economic conditions increased steadily.The shape boundary of the regions in each land use type tends to be complex,the degree of landscape fragmentation increased,and ecological functions were affected.The correlation between the nodes inside a complex network became larger,the network became tighter,and the stability became stronger.The nodes of landscape shape index were most closely connected with other nodes and played the most important role in the process of network information transmission.(4)Overall,the ecological environment of the study area is of poor quality.The change of land use type is the Granger reason for the change of ecological environment quality.The conversion of cultivated land to industrial and mining land has a strong side effect on the quality of ecological environment.At the same time,the loss of ecological environment quality is different with various types of land use change.(5)Comprehensively considering land use and ecological environment of the study area,the land use of Pingshuo opencast mining area is mainly ecological land,and the construction land is increasing continuously.The order degree of regional land use is low,and the structure is poor.According to the characteristics of land use and social development in the study area,the optimization scheme of land use structure with priority given to maximizing ecological benefits can be adopted.