Study On Landscape Ecological Risk Assessment Of Western Jilin Based On Land Use Change

Land resources are the basis for human survival and development.,however,with the acceleration of urbanization,complex natura l activities and human activities have a series of adverse effects on regional ecosystems.Land use change is an important carrier of human activities on the surface.The western part of Jilin,in a semi-humid and semi-arid climate zone,is a typical agro-pastoral ecotone.The ecological environment is fragile and sensitive,which is highly susceptible to human activities and climate change.Relied on the coupling perspective of geography and ecology,Landscape ecological risk assessment uses regional landscape as the evaluation object to quantitatively evaluate the ecological effects of land use change.Based on the land use data of 1975,2000 and 2015,this paper analyzes the temporal and spatial variation of land use in western Jilin by using land use degree and land use dynamics model,and analyzes the ecological problems caused by land use change.On this basis,the study area is divided into much risk assessment community and the landscape pattern index such as landscape fragmentation degree,landscape dominance and landscape separation degree are selected to construct the landscape ecological risk assessment model,which analyzes the spatial and temporal changes of ecological risk in western Jilin Province from 1975 to 2015.On this basis,we can analyze the impact of climate and human activities on them,and provide suggestions for land resource management in different ecological risk zones.The main conclusions drawn are as follows:(1)The spatial pattern of land use in western Jilin Province has changed greatly from 1975 to 2015: in the past 40 years,the land use degree in western Jilin increased,the land use development degree in the eastern part of the study area was higher;the land use diversification index declined,and the level of diversification of land use in the western part of the study area was relatively higher,the land use structure was more complicated;the land cover status index was declined,the macroscopic ecological condition was worse,and the ecological status in the north central part of the study area was better;the land use dynamic degree was higher in the eastern and southwestern parts of the study area from 1975 to 2000,and was higher in western and southern regions from 2000 to 2015;the land use diversification index and the land cover status index decreased,which show the regional macro-ecological conditions deteriorated.The study area faces a series of ecological environments problems such as land salinization,grassland degradation,and wetland shrinkage.(2)From 1975 to 2015,the landscape fragmentation degree in western Jilin increased,the landscape separation decreased,and the landscape superiority increased,which shows that in the past 40 years,the land landscape of the study area has become more diversified,the degree of landscape fragmentation has intensified.And the degree of fragmentation in the west is higher in the study area;(3)The low-risk areas of landscape ecology are mainly distributed in the northeast and northwest of the study area.And the high-risk and higher-risk areas are concentrated in the central and southwest of the study area.From 1975 to 2000 the high-risk areas and higher-risk areas were expanding.From 2000 to 2015 the low-risk areas showed a contraction trend,and the ecological risks were positively correlated in space;the temperature had a positive impact on the landscape ecological risks,and precipitation had a negative impact on it.