Landscape Ecological Risk Evaluation Of Lanxi City Cluster And Its Early Warning Research

With the concept of ecological civilization,the country has paid more and more attention to ecological restoration and nature protection,and at the same time implemented a series of prevention and control measures,such as agricultural land protection,desertification prevention and control,water conservation,etc.,aiming to achieve ecological sustainable development.Especially for northwest China,which has a fragile ecological environment,ecological construction has gradually become an important cornerstone for achieving economic development.The natural ecological barrier area of the Qinghai-Tibet Plateau is an important part of China’s ecological pattern,and the Lanxi urban agglomeration not only relies on it but also lies in the upper basin of the Yellow River,which plays an important role in maintaining China’s territorial security and ecological safety.Lanxi urban agglomeration is special among Chinese urban agglomerations because it covers a large area of less developed regions and backward regions,its per capita GDP is lower than the average level of western China and the whole country,and its economic development mainly relies on primary industry,which caused a series of environmental problems.This paper takes Lanxi urban agglomeration as the research object,firstly,by analyzing four phases of image data in 2000,2005,2010 and 2015,the dynamic evolution of landscape pattern is portrayed by analyzing the evolution status of landscape types,and the study mainly selects 10 indicators such as maximum patch index,aggregation degree and spreading degree from two dimensions of patch type level and landscape level,and uses Fragstats software was used for calculation.Secondly,the risk evaluation indexes such as fragmentation degree,disturbance degree,dominance degree and vulnerability degree are used to construct a landscape ecological risk evaluation model,divide the watershed into 1124 risky plots,and racterize the spatial and temporal variation characteristics of landscape ecological risk from 2000-2015 using ordinary kriging interpolation in geostatistics.Finally,on this basis,the FLUS model was used to simulate the landscape types of the Lanxi urban agglomeration in 2030 by combining the data of elevation,temperature,precipitation and road network,and to evaluate and warn the landscape ecological risk of the Lanxi urban agglomeration in 2030.The results show that:(1)Grassland is the landscape with the highest coverage in the Lanxi urban agglomeration.In terms of landscape pattern,the maximum patch index and agglomeration of all types of landscapes varied greatly from 2000 to 2015,mainly due to the fact that the Lanxi urban agglomeration is in a period of high speed economic development and human activities are disturbing the landscape more strongly.(2)From 2000 to 2015,the landscape ecological risk of Lanxi urban agglomeration showed a trend of"high in the west and low in the east".15 years later,the overall landscape ecological risk showed a decreasing trend,and the sum of high,high and medium landscape ecological risk areas decreased from 50,910.88km~2 in2000 to 29,627.64km~2 in 2015.(3)In 2030,the construction land in the Lanxi urban agglomeration is still in the trend of rapid growth,and in 2030,the overall landscape ecological risk of the urban agglomeration decreases,and the very high risk area,high risk area and medium risk area gradually turn into low and very low risk areas.The results of the study indicate that the ecological protection of the Lanxi urban agglomeration has been continuously strengthened,but the areas with higher risks still need to be taken seriously and ecological protection strategies should be implemented according to local conditions.