Spatial And Temporal Differentiation Of Landscape Ecological Environment Risks In Ili Region And Analysis Of Its Influencing Factors

Landscape ecological environment risk assessment is based on the change of surface landscape,and through the analysis of the coupling relationship between landscape pattern and ecological environment process,the landscape ecological environment risk index is constructed to reveal the impact of human activities and natural environment on regional landscape environment from multiple scales and long time series.Landscape ecological environment risk assessment can reveal the changes of ecological environment caused by the changes of landscape elements and ecological processes in the region,which plays an important role in the improvement and sustainable development of regional ecological environment.Ili is located in the arid region of Xinjiang Uygur Autonomous Region.It has rich natural and cultural resources and diverse landscape types,but its ecological environment is fragile and sensitive.In the past 20 years,with the change of natural environment and human activities,the landscape in Ili has been disturbed more and more,which makes the potential ecological environmental problems in this area increasingly prominent.In this context,this article to Ili area as the research object,in the region 2000,2005,2010,2015 and 2018,five series of Landsat remote sensing image data as the foundation,extraction of landscape types and landscape pattern index and calculation,and building the landscape ecological environment risk assessment model,analysis and evaluation of Ili region in 2000-2018 space-time evolution of landscape structure and landscape ecological environment risk degree,to reflect the status of Ili region ecological environment change.At the same time,climate data,elevation data,human disturbance index and other information are used to explore the influencing factors of landscape ecological environment risks from two aspects: natural factors and human activities,so as to provide scientific decision-making basis for ecological environment protection,governance and ecological risk avoidance in the later period of Ili region.The main conclusions are as follows:(1)During the study period,grassland and cultivated land were the most important landscape types in Ili,accounting for more than 78% of the total area.The area of forestland and grassland showed a trend of continuous decrease,while that of construction land,water area and cultivated land showed an increase trend.There was a strong shift among various landscape types,among which the out-turn area of grassland was the largest,accounting for 3.20% of the total area of the study area.On the whole,in the past 20 years,the change rate of land use in Ili was 0.1299,and the overall landscape pattern changed little.(2)On the whole,the degree of separation,connectivity and fragmentation of the landscape in the study area all show an upward trend.The areas of different types of landscape tend to be even,the shape of patches becomes more complex,and the overall landscape pattern is diversified.In the overall landscape pattern,the dominance degree of farmland,construction land and water area landscape is on the rise,while the dominance degree of grassland,woodland and unused land landscape is on the decline.Different landscape types have obvious differences in patch heterogeneity,fragmentation and shape complexity.(3)During the study period,high,medium and low ecological environmental risks were widely distributed in Ili.In terms of spatial distribution,the spatial distribution of ecological environmental risks in the study area is mainly characterized by the spatial distribution pattern of high in the east and low in the west,high in the north and low in the south,and low and high in the center.In the shift of the center of gravity,there are great differences in the direction and distance of the ecological environmental risk levels at different time periods.There is a certain rule in the transformation between the levels of ecological and environmental risks.The most transferred area is medium ecological and environmental risks,and the transferred area accounts for 8.04% of the total area of the study area.However,the higher ecological environmental risk has a wide range of transfer to other levels.On the whole,the landscape ecological environment risk in Ili area is decreasing.(4)In 2000-2018,Ili region landscape ecological environment risk and negatively correlated with temperature,and was positively correlated with precipitation,shows that high temperature for the landscape ecological environment in the area of Ili have a positive impact,while higher rainfall in Ili region of landscape ecological environment have a negative impact,at the same time,different levels of ecological risk in different terrain gradient distribution difference is obvious.Human activities also have a certain impact on the landscape ecological environment risk in Ili area.The landscape ecological environment risk in the heavily disturbed areas is the greatest,while the landscape ecological environment risk in the moderately disturbed areas is the lowest.