Analysis On Land Use Pattern Change And Ecological Security Evaluation In Tianshui City

In recent years,with the level of social and economic development,the land use pattern has undergone significant changes.Since 2009,Tianshui City has been classified into Guanzhong-Tianshui Economic Zone,the economic development speed has increased,and the land use structure has been reduced,Therefore,Tianshui City,land ecological security there is a certain risk,scientific judgment and prediction of land ecological security level has a certain value.In this paper,the land use data of Tianshui City in 2005,2010 and 2015 were used to analyze and analyze the land use type of area with ArcGIS software.On this basis,the CA-Markov model is constructed to predict the land use pattern in 2020.Using landscape ecology,the landscape pattern index and the total ecological environment of Tianshui City during the study period were calculated and analyzed.This paper constructs the PSR model of the study area,combines the actual situation of the study area and the index system of each landscape index to carry out the evaluation of land ecological security in 2005-2020,and obtains the following conclusions:(1)Tianshui City,the advantages of land use types for arable land,woodland,grassland and urban land.Grassland and urban land use change is more active,the maximum change range of 1.3%and 4.8%respectively.Cultivated land and forest land change is relatively stable,the range of change is about 0.5%.The land use type with obvious change trend is unused land and water area.The grassland and unused land were mainly transferred to the cultivated land,woodland and urban land;the urban land and water transfer were less,and the land was transferred to the forest land,the grassland and the urban land were mainly transferred to the grassland.(2)Using the CA-Markov model to simulate the land use pattern of Tianshui City in 2020,this paper analyzes the trend of land use pattern in the next five years and the change of landscape pattern and ecological value in 2005-2020,The trend of land use change is stable,the area of cultivated land and unused land is decreasing,and the area of forest land,grassland and construction land is increasing continuously.Landscape fragmentation is high,the landscape elements tend to agglomeration between.The increase of forest land and grassland increases the total value of ecological environment,but the decrease of per capita ecological environment value is mainly due to the increase of population.(3)The results show that the value of land eco-environmental stress is increasing from 2005 to 2015,and the value of land eco-environmental status is increasing in the period of 2015-2020.Land The eco-environmental response index decreased first and then increased.The classification of ecological security,2005,2010 for the risk level,2015 for the sensitive level,to achieve a good level in 2020.