| In recent years,As China's economic strength continues to increase,large-scaled urbanization process and the quickly population growth,the spatial composition of regional land utilization significantly changes,it also leads to the fragmentation and vulnerability of regional landscapes,as well as making the development of the city deviate from the road of harmonious development between human and nature.Studying the changing characteristics of regional land utilization can not only reproduce the dynamic process of surface landscape,but also intuitively and accurately describe the impact of human activities on land utilization.It is an important means of regional ecological environment protection and management,has theoretical and practical meaning for regional landscape protection and sustainable development.Loufan County is the main source of water conservation and ecological barrier in Taiyuan City.With the rapid development of the county,a series of unreasonable land use phenomena have emerged,resulting in environmental erosion,low forest cover,and ecological deterioration,which makes Loufan one of the typical ecologically fragile areas on the Loess Plateau.Based on the relevant theories of landscape ecology,as well as the support of Arc GIS,Fragstats,Geo Da and other tools,this paper analyzes the dynamic changes of land utilization in Loufan County between 1990 and 2018,carries out the spatial scale research of the landscape pattern of the county,and explores the landscape pattern change characteristics of the county on the basis of best analysis granularity.It turns out:(1)Between 1990 and 2018,the area of cultivated land,forest land and grassland in Loufan County showed a decreasing trend,but the changing area of water did not change much and showed a trend of stabilization;The change of land use types in Loufan County is mainly based on the changes of urban and rural industrial and mining residential land and unused land.Due to the acceleration of urbanization,and the rapid increasement of thedensity of human beings,the area of urban and rural industrial and mining residents has increased significantly.The change speed of landscape types in different periods showed different characteristics,overall,land utilization changed rapidly during this period.(2)Through the particle size effect map of landscape pattern index and the model of information loss evaluation,the best spatial analysis granularity of study on the landscape pattern of Loufan County is confirmed to be 40 m.Based on the optimal spatial analysis granularity,I analyzed the landscape pattern changes in Loufan County.At the level of landscape,the landscape of Loufan County is diversified,the shape tends to be simplified,and the fragmentation of the pattern is deepened.At the level of type,among the various landscape types in Loufan County between 1990 and 2018,the dominant degree of forest land is the largest,and the dominance of urban and rural industrial and mining residents has increased greatly.The degree of fragmentation of cultivated land is the highest,and the degree of dispersion is relatively largest,and in the period from 2000 to 2010,the degree of fragmentation of cultivated land is rapidly deepened.The landscape change of urban and rural industrial and mining residential land is most affected by human activities,and the disturbance of grassland by human activities is relatively small.(3)Based on the land utilization change in Loufan County,the regional ecological risk assessment is carried out,and the result turns to be basically in line with the actual situation of land utilization.Between 1990 and 2018,the ecological risk level of Loufan County showed a high-level,four-week-low circle structure in the center of the county.The ecological risk of the forest was gradually reduced by the Miaowan Township-Loufan Town-Majiazhuang Township.The area of the district and the higher ecological risk zone gradually spread from the central part of the county to the west of the county.(4)The ecological risk of Loufan County tends to increase,and the regional environment deteriorates.The main performances are the area ofhigh and higher ecological risk zone have increased significantly,while the area of lower and low risk zone have been decreasing.This is mainly due to unreasonable land utilization patterns and the rapid growth of the regional population and quick development of economy.The ecological risk index of land utilization in Loufan County has a significant positive correlation in spatial distribution,and its spatial distribution presents a pattern of agglomeration distributionBased on the above research,this paper systematically describes the evolution process of landscape pattern in Loufan County from 1990 to 2018,and carries out ecological risk assessment based on land utilization change,in order to optimize the future landscape pattern,protect the ecological environment,and provides reference for its sustainable development in Loufan County.It also provides quantitative decision-making basis and theoretical support for regional ecological risk management.As far as this paper is concerned,the regional ecological risk assessment is still in the preliminary stage of exploration.Since there are no technical guidelines for regional ecological risk assessment that have universal characteristics,it is very urgent and necessary to develop a universal guideline for evaluating regional ecological risks. |
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