Study On Landscape Pattern Optimization Of Large-scale Surface Coal Base In Semi-arid Steppe Based On 3S Integrated Technology

Human beings have thousands years of civilization history of coal mining and utilization.The important position of coal in energy utilization has been unshakable in China and even the world.The coal resources in eastern China are gradually exhausted.In order to further meet the demand of China's energy,during the“12th Five Year Plan”and“13th Five Year Plan”,the Chinese government proposed to speed up the strategic shift of coal development to the west,and focus on the construction of nine large-scale coal bases in Northwest China,and accelerate the closure and exit of coal mines outside the large-scale coal bases.The semi-arid steppe in Northwest China has the characteristics of cold,drought,poor soil,high evaporation intensity and short plant growth period.The grassland ecological background conditions are extremely fragile,and it is a region with extremely serious landscape ecological degradation.Most of China's surface coal mines are located in arid and semi-arid regions.The exploitation of coal leads to a series of landscape ecological disturbance and ecological environment problems,such as landscape structure defect and dysfunction.Therefore,it is very necessary to optimize the landscape pattern effectively,which includes realizing the maximum overall recovery with the minimum manual intervention,comprehensively understanding the landscape ecological problems and the complexity of the impact of mining on the landscape ecology.However,the impact of surface coal mining on the landscape pattern of semi-arid steppe is not clear,which leads to the existing landscape pattern optimization methods that cannot be targeted and scientific to solve the landscape ecological problems of large-scale surface coal bases in semi-arid steppe.The objectives of this study are:1.study on the theory and method of landscape pattern optimization based on guided self-restoration;2.put forward the landscape classification system of large-scale coal bases in semi-arid steppe;3.carry out full landscape ecological investigation in the study area;4.define the connotation,standard,assessment index system and model of landscape ecological health for large-scale coal base in semi-arid steppe;5.in-depth study on the impact of surface coal mining on grassland landscape pattern;6.determine the landscape pattern optimization plan of large-scale coal base in semi-arid steppe.Finally,the following research results are obtained:(1)Based on the principle of landscape classification of large-scale coal bases,this study fully considers the ecological attributes of land on the basis of genetic land classification,integrates the pattern,process and function theory of landscape ecology,and adopts the top-down decomposition classification method,draws lessons from the hierarchical nomenclature of biological classification,and finally constructs the landscape classification system of large-scale coal bases in semi-arid steppe,which includes 4 categories of landscape community,16 categories of landscape class,62categories of landscape family,and more than 200 categories of landscape species.Moreover,on the basis of landscape classification and investigation,this study conducts an in-depth analysis on the landscape pattern evolution of Shengli large-scale surface coal base in Xilinhot City from 2002 to 2017.The analysis results show that:1)all kinds of human disturbance lead to the increase of grassland landscape patches,the fragmentation of landscape,the decline of landscape connectivity,the increase of landscape diversity,the complexity and irregularity of landscape shape,the dispersion of landscape patches,the enhancement of landscape heterogeneity and complexity,and the decline of landscape stability;2)grassland landscape is the matrix of the study area.Mining landscape,urban landscape,industrial storage landscape and road network landscape expand year by year and occupy a large number of grassland landscape,resulting in the gradual decrease of grassland landscape and the increase of unhealthy grassland landscape year by year.(2)In this study,a Semi-Arid Steppe Desertification Index(SASDI)model based on the Albedo-MSAVI feature space was proposed.The results show that SASDI model has a high correlation with surface soil organic matter(R~2=0.7585).The model makes full use of multi-dimensional remote sensing information,which is conducive to the quantitative analysis and continuous monitoring of desertification in semi-arid steppe regions.At the same time,this study proposes a Semi-Arid Steppe Salinization Index(SASSI)based on SI-Brightness feature space,and analyzes the relationship between SASSI and surface quantitative parameters.The results show that the SASSI model has a high correlation with surface soil salinity(R~2=0.7698),and makes full use of multi-dimensional remote sensing information.SASSI model can obtain soil salinization information of semi-arid steppe regions accurately,effectively and conveniently.(3)In this study,CVORE(Condition,Vigor,Organization,Resilience,and Ecosystem services function)model was constructed for landscape ecological health assessment of large-scale coal base in semi-arid steppe.On this basis,the paper puts forward the index system of landscape ecological health assessment of large-scale coal base in semi-arid steppe,defines the connotation of landscape ecological health of large-scale coal base in semi-arid steppe,and formulates the standard of landscape ecological health for large-scale coal base in semi-arid steppe.At the same time,based on the landscape ecological health assessment,this study also analyzed the impact of surface coal mining on landscape ecological health of semi-arid steppe.The results show that:1)the mild unhealthy landscape is mainly located around the area with more human disturbance.The moderate unhealthy landscape is mainly the industrial square landscape of mining area.The severe unhealthy landscape is basically the open-pit of mining area.The proportion of each health level presents a normal distribution mode of“less at both ends,more in the middle”.The unhealthy landscape increases year by year,and the healthy landscape gradually decreases;2)the spatial and temporal distribution characteristics of landscape ecological health in the study area are extremely obvious and single.The regional landscape ecological health with high water content is excellent,and the regional landscape ecological health with more human interference is poor;3)according to the development mode of large-scale surface coal base,the types of disturbed landscape formed in the process of coal surface mining and the evolution process of landscape ecological health in the study area,the impact of coal surface mining on healthy grassland is divided into four types:disturbed degradation type,disturbed degradation recovery type,stable health type and fluctuating type;4)the driving factors of spatial distribution and change of grassland landscape ecological health in the study area are water,surface mine,city,agriculture,industry,road network and elevation.Coal surface mining has a significant impact on landscape ecological health of grassland.(4)In this study,the concept model of the impact of large-scale surface coal base on the landscape ecology of semi-arid steppe is proposed.The objective,principle and theory of landscape pattern optimization in mining area are clarified.Based on this,the theory and method of landscape pattern optimization in mining area based on guided self-restoration are put forward.In the research process of guided self-restoration of Shengli large-scale coal base in Xilinhot City,the Modified Landscape Disturbance Index(MLDI)was put forward.Combined with the landscape ecological health assessment,buffer zone analysis and the landscape ecological function contribution rate,the spatial distribution of the impact of large-scale surface coal base on the landscape ecological health of semi-arid steppe was established.On this basis,three landscape ecological restoration regions(Engineering restoration patch,artificial maintenance patch and natural restoration patch)and corresponding guided self-restoration suggestions are proposed.Finally,the purpose of overall landscape function improvement and sustainable development is achieved with the minimum cost,and“landscape pattern optimization”is realized.In the research process of the Shengli large-scale coal base landscape pattern optimization in Xilinhot City,the landscape pattern was optimized by constructing a resistance surface based on multi-regulation fusion and adopting the minimum cumulative resistance model.Based on the newly constructed"source"landscape,ecological corridor,ecological node and constructed wetland,this paper puts forward a landscape pattern optimization model of"one ring,two vertical,two horizontal,eight core,ten node and multi corridor".The“landscape pattern optimization”model proposed by this research is based on the inherent restoration ability of the landscape ecology of large-scale coal bases and the impact of mining on the landscape ecology,and“helps”large-scale coal bases to self-repair by constructing a potential landscape pattern to make damaged landscape through its own active feedback,the ecology continues to spontaneously move towards recovery and a virtuous circle,achieving"guided self-restoration".At the same time,this study combines a series of restoration strategies at three scales:coal base,mining group and mining area,and proposes a multi-scale guided self-restoration landscape pattern optimization system.On the basis of landscape ecology,surveying and mapping science and technology,land resource management,geography,ecology,surface mining,restoration ecology,mine ecology,land reclamation and ecological reconstruction,taking Shengli coalfield in Xilinhot City,a typical large-scale coal base in semi-arid steppe,as an example.This paper puts forward the theory and method of guided self-restoration landscape pattern optimization,and the research system of“landscape classification,investigation and monitoring of large-scale coal base?landscape ecological health assessment of large-scale coal base?the impact of surface coal mining on the landscape pattern of semi-arid steppe?landscape pattern optimization of mining area based on guided self-restoration”.This study aims to provide reference for landscape classification,landscape ecological assessment,impact of mining on landscape ecology,landscape pattern optimization,landscape ecological planning,ecological planning,urban planning,landscape ecological restoration and other similar research regions around the world,such as mining cities and large-scale coal bases.This paper has 52 Figures,24 Tables and 390 References.