| As one of the major production areas of energy resources in China,Northern Shaanxi boasts abundant reserves of coal,oil and natural gas,becoming an important supply area as well as an energy and heavy chemical industrial base in China’s West-to-East Coal Transportation and West-to-East Gas Transmission.However,located in the arid-semiarid region,this region is one of the areas with the most serious water and soil erosion on the loess plateau.The ecological environment is very fragile,susceptible to damage and difficult to recover.The development of energy resources has destructive effect on the fragile ecological environment in Northern Shaanxi and makes the ecological condition even worse in some areas,resulting in irreversible impact on the ecological environment.In this study,with ecologically fragile Northern Shaanxi as the object,we have established the ecological security database,model library from the perspective of regional ecological environment security,energy security and sustainable development.We have processed data and made dynamic model analyses in terms of time and space using GIS technologies;identified the ecological environment and dynamic change characteristics of the ecological environment effect in the energy development zone;made comprehensive and quantitative assessment of the ecological efficiency and ecological security dynamics of energy development in ecologically fragile areas and worked out the influencing process and influencing mechanism of energy development on ecological security in fragile environments.The findings hold theoretical significance and practical effect to the deepening of the theories of and approaches to the study of relationship between population and land,and to the promotion of a coordinated and sustainable development of environment in key energy areas in West China.The main conclusions are as follows:(1)The land use is in a degradation and a development phase in Northern Shaanxi and its energy development zone from 1980 to 2010,respectively.① In Northern Shaanxi,the grassland is superior in the occupied area,which is over 40%;the cultivated land area and forest land area are in the second place.In a period from 1980 to 2010,the areas occupied by the cultivated land,water area and unutilized land are decreased,in which the cultivated land is under the biggest change.Quantitatively,during 30 years,the area occupied by the cultivated land has been decreased 476797.86 hm2;the area occupied by the forest land has been increased 661400.49 hm2.Structurally,with the change contribution rate of 46.55%,the forest land is the biggest item,which is followed by cultivated land and unutilized land.② During the period from 1980 to 2010,the land use in Northern Shaanxi is in an adjustment phase.In the view of working section of different energy resource,the land use in northern coal working section is in a development phase,which has the highest land use degree change rate 8.65%;the land use in southern coal working section and petroleum working section is in an adjustment phase;the land use in natural gas working section is in a development phase all the time,but its development rate gradually decreases.(2)The vegetation cover increased in Northern Shaanxi and its energy resource zone from 1980 to 2010.From the perspective of different land-use type,the vegetation cover change rate of forest land is-0.013/10a during the period from 1980 to 2010,which shows a degradation trend;it is greatly obvious that the vegetation cover of unutilized land has been improved,secondly it is followed by construction land,cultivated land and grassland.From the perspective of working section of different energy resource,the vegetation cover in southern coal working section shows a degradation trend;the vegetation cover in northern coal working section has obvious improvement,secondly it is the natural gas working section and petroleum working section.(3)The change rate of average value of ecosystem integrated service function has a rising trend in Northern Shaanxi and its energy resource zone over 30 years.From the perspective of different land-use type,the forest land has the largest integrated service function,secondly it is followed by cultivated land,grassland,construction land and unutilized land;during the period from 1980 to 2010,the average value quantity and the total value quantity of various land-use show a rising trend,in which in terms of the average value quantity change rate of ecosystem integrated service function,the forest land occupies the largest change rate,secondly it is cultivated land,construction land,grassland and unutilized land.In view of energy resource working section,the integrated service function in all energy resource working sections shows the rising trend,in which the increasing degree of petroleum working section is the most obvious,secondly it is followed by southern coal working section.The integrated service function of northern coal working section and natural gas working section changes slowly.(4)The soil heavy metals has a high ecological risk in Northern Shaanxi and its energy resources zone.① There is obvious aggregation of various heavy metals in the soil of Northern Shaanxi.The pollution is relatively severe.Among the heavy metals of soil in Northern Shaanxi,except the average content of Cd reaches the national secondary standard and its maximum content exceeds the national secondary standard,the average content of other heavy metal,such as Hg,Pb,Zn and Cd,has exceeded the soil background value of Shaanxi Province;the maximum content of As,Cu and Ni has also exceeded the soil background value.② In Northern Shaanxi,the different heavy metals risk all increases from south to north and from southeast to northwest,and indicates the homology.The heavily hazardous area of heavy metal covers the largest scope with 33.21%of total area;it is followed by slightly hazardous area,relatively hazardous area,medium area and hazardous area.③ From the perspective of working section of different energy resource,the heavy metal risk successively decreases in sequence of natural gas working section,northern coal working section,petroleum working section and southern coal working section.The diffusion of soil heavy metal in southern coal working section is severe,and the diffusion in other working section is relatively weak;the influence of heavy metal pollution in petroleum working section is small.④ The ecological hotspot zone mainly locates the south central of Northern Shaanxi,which covers 22.66%of the total area.The medium-low hotspot zone occupies 79.07%of the total area in hot spot region.In the medium-low hotspot zones,the central part of the Yan’an region and Luochuan county in the southern part of Northern Shaanxi shall become the conservation priority zone of corresponding soil heavy metal pollution.(5)The ecological security comprehensive index is not in a safety level in Northern Shaanxi and its energy resource area from 1980 to 2010.① The southern coal working section is in the medium level,and the other working sections all are in unsafe level.②During the period from 1980 to 2010,the MK test value of ecological security index in Northern Shaanxi is 0.33,and shows a rising trend.From the perspective of energy resource working section,the ecological security of the southern coal working section shows a declining trend,but ecological security of the petroleum working section,northern coal working section and natural gas working section all show a rising trend.③ It is greatly obvious influence of ecological response change of Northern Shaanxi on the ecological safety.From the perspective of energy resource working section,all working sections shall enhance the enforcement of environmental protection measures,except that the northern coal working section shall decrease the energy resource development,which makes the ecological safety switch to higher level;on the basis of ecological stress decrease for the southern coal working section,it shall strengthen the ecological environmental protection and prevent the continuous degradation of ecological environment;the natural gas working section shall control the ecological stress,ecological state and ecological response,as well as improve the environment and rate;if the ecological stress of petroleum working section is not beyond the controlled scope,it shall take the environmental management and protection as the principal thing,and maintain the improvement rate of current ecological environment.③ The land ecological security comprehensive index in Shenmu-Fugu mining area is 0.35 and is in unsafe level.The land ecological safety along both sides of the riverway is generally low.The proportion of relatively unsafe zone is the largest 33.16%,which mainly locates mu su desert in the downstream basin of Tuwei river and the western part of midstream of Kuye river;the critical safety zone mainly locates on the downstream and southwest part of Kuye river(Wulunmulan river);the proportion of extremely unsafe zone is the smallest,and mainly locates on the midstream of Kuye river.The innovations and breakthroughs made in this study are as follows:① In this study,data processing is based on the MATLAB programming language.Executable files(EXE)for multiple analysis methods have been established with considerations from various angles and through GUI design and development.Improved grid computing efficiency has enabled the intelligent processing of the time series geographic grid data.② In this study,we combine the biodiversity protection value with the potential risk level of soil heavy metal and examined the ecological hotspot areas in Northern Shaanxi for the perspective of the possibility of eco-diversity and soil heavy metal pollution.Depending on the actual ecological environment,it gives the conservation priority zone of corresponding soil heavy metal pollution on the basis of hotspot zone.This approach offers a new thinking mode for the determination of areas with conservation priority in ecological environment,and provides theoretical basis for competent authorities to conduct ecological rehabilitation and to further manage and protect the ecological environments.③ In this study,we attach importance to the dynamic evaluation of ecological efficiency and ecological safety of energy resource development.The ecological security index of energy zone in Northern Shaanxi is calculated on the basis of time series grid data.Its ecological safety evaluation possesses the continuity.It indicates the difference in time and space.In addition,the result is specific.Therefore,it can analyze the dynamic change process of ecological safety,has a good guidance to the practice and benefits to protection and management of ecological environment. |
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