Spatiotemporal Changes Of Landscape Pattern And Its Vulnerability Of Liangcheng County

With the rapid development of economy and the implementation of a series of major ecological projects in China,the surface landscape has been constantly changing,and the landscape changes will inevitably affect the various ecological processes and functions,which is manifested by the strong division and transformation of the landscape.The landscape changes have caused the ecological environment problems of high sensitivity,vulnerability and frequency.Therefore,the research on landscape dynamic change and its vulnerability has become a hot spot and important field of landscape ecology.The scale problem is not only the basis of landscape ecology,but also one of the core issues of the study of landscape dynamic change and its vulnerability.Taking Liangcheng County as an example,this paper studies the landscape pattern change and its vulnerability in the past 37 years under the premise of analyzing the spatial scale effect of landscape pattern.Liangcheng County,located in the southern part of Ulanqab City,Inner Mongolia Autonomous Region,is now in the stage of rapid urbanization.Behind this bright prospect,it faces the problem of unreasonable configuration of the landscape pattern,and Daihai lies in Liangcheng County,playing extremely important ecological effect,but due to various reasons,the area of Daihai has been shrinking over the years,the situation is grim.Therefore,this paper takes Liangcheng County as a study area,based on GIS,Fragstats,GS+,GeoDa and other platforms,combined with landscape type data,this paper analyzes the change process of landscape type from 1980 to 2017 in Liangcheng,and explores the landscape pattern change on the basis of determining the best spatial analysis granularity.At the same time,we try to select the appropriate spatial extent to evaluate the landscape pattern vulnerability in Liangcheng,focusing on the spatial-temporal differentiation and spatial correlation of landscape pattern vulnerability.The preliminary conclusions are as follows:(1)Cultivated land and grassland were the dominant landscape types in Liangcheng County.From 1980 to 1995,the changes of cultivated land,forestland and grassland were the main changes in Liangcheng,especially the change of grassland to cultivated land.Landscape dynamic changes were the most dramatic in 1995-2010,with significant changes in cultivated land,forestland,grassland,water and residential land,especially in the conversion from cultivated land to grassland.From 2010 to 2017,the landscape change was relatively low.The area of cultivated land,forestland and grassland had basically reached a stable state,and residential land increased rapidly.As far as Daihai is concerned,Daihai was in a shrinking state during the period of 1980-1995.During the period of 1995-2010,Daihai was rapidly shrinking.From 2010 to 2017,the main landscape types around Daihai changed from marsh to water,and Daihai had been expanded to some extent.(2)The study of spatial scale effect showed that the best spatial analysis granularity of Liangcheng was 70 m,and the most suitable spatial amplitude is the grid size of 3km × 3km.The landscape pattern study based on the best spatial granularity showed that the landscape fragmentation degree of Liangcheng County gradually deepened at the landscape level from 1980 to 2017;the landscape shape had been complicated,and the landscape type composition was more diverse,and agglomeration degree of different patch types in the landscape reduced gradually in 1980-1995;while landscape shape had been simplified from 1995 to 2017,landscape type composition was more singular,and some dominant patch types in the landscape formed better connectivity.(3)Landscape pattern vulnerability increased significantly in some areas of Liangcheng County from 1980 to 1995 and decreased from 1995 to 2017.In space,the high-value areas of the landscape vulnerability index were concentrated in the central and southeastern parts of Liangcheng.The reason for the high vulnerability of the central part of Liangcheng is that the landscape system was mainly controlled by cultivated land,and the high degree of dominance led to high landscape sensitivity.Moreover,the lower landscape diversity and uneven spatial distribution resulted in lower landscape adaptability.The reason for the high vulnerability of the southeast of Liangcheng is that the landscape system was mainly controlled by cultivated land and grassland,and higher dominance of cultivated land and grassland resulted in higher landscape sensitivity to a certain extent.At the same time,landscape fragmentation in the study area was serious,especially grassland.(4)On the whole,the degree of landscape pattern vulnerability was dominated by moderate and higher vulnerability in Liangcheng County,especially moderate vulnerability.There was a strong spatial positive correlation phenomenon in landscape pattern vulnerability in Liangcheng County.In 1980,the “high-high” value area of the landscape vulnerability index was concentrated in the central and southeastern part of Liangcheng.Compared with 1980,the distribution of “high-high” value area in the central part of Liangcheng was significantly reduced in 1995.During the period of 1995-2010,the distribution of the “high-high” value area in the central part of Liangcheng was significantly expanded,and the “high-high” value area appeared in the northern part of Maihutu Town.The “high-high” value area in the central part of Liangcheng was almost disappeared in 2010-2017,which indicated that landscape pattern vulnerability in the central part of Liangcheng has been alleviated to some extent during the period.(5)The main suggestions for the optimization and control of landscape pattern in Liangcheng County are as follows: 1)Strengthen the rational use and protection of cultivated land,forestland and grassland,reduce the unreasonable disturbance and destruction of cultivated land,forestland and grassland by human activities,and reduce the degree of splitting and fragmentation of cultivated land,forestland and grassland;2)Enhance the diversity of landscapes and promote the relative homogenization of landscape distribution;3)Focus on the protection of the Daihai and its surrounding environment,reduce the irrational development and utilization of water resources of the Daihai,and strengthen the protection of the Daihai wetland.