| As an important carrier of human production and life,land is also an important material basis for human survival.Since the 18 th National Congress,China has put forward requirements for the construction of ecological civilization.It is of great significance to combine land use and ecological environment construction to form a life community of mountains,rivers,forests,fields and lakes.Land use change is an important factor causing global climate and environmental change,and the dynamic change of landscape pattern must be accompanied by land use change.At present,most of the research on mega cities such as Tianjin focuses on land use or ecological environment.Therefore,this paper takes Tianjin as the research area,combines image data with socio-economic data,studies the law of land use landscape pattern change in Tianjin,and deeply analyzes the factors affecting landscape pattern change in Tianjin,Combined with the change of ecological environment quality,this paper puts forward some suggestions on the future land use of Tianjin.The main results are as follows:(1)From 2000 to 2020,the dynamic degree of land use type change gradually increased,and the dynamic degrees in the four time periods were 1.06%,3.08%,3.80% and 21.5%respectively.The change of land use types is more drastic,and the overall dynamic degree has reached 5.46% in the past two decades.The maximum and minimum values of single land use dynamics are construction land and forest land,which are 3.83% and0.06% respectively;Among all land use types,the land use type with the highest transfer out amount is cultivated land,and the transfer out amount reaches 166161hm2,of which the area converted from cultivated land to construction land is 85999hm2.The land use type with the highest transfer in amount is construction land,reaching 114092hm2.The main transfer in source of construction land is cultivated land.(2)From 2000 to 2020,the landscape pattern of Tianjin has changed significantly.Based on the landscape level,the NP,PD and LSI indexes have increased significantly,from 4528 to 10712,0.39 to 0.90 and 42.98 to 62.52 respectively.The LPI index as a whole has also increased slightly,from 31.75 to 42.63,indicating that the fragmentation of the whole landscape in Tianjin has deepened and the dispersion between landscape patches has increased,The distribution of various landscape types in the whole city tends to be complex.The remaining cohesion,division,AI,SHDI and Shei indexes show a fluctuating change of first decline and then rise.In addition,the landscape patterns of districts and counties in Tianjin are quite different.The urban landscape aggregation degree continues to focus on about 99,and other districts and counties generally do not exceed 95.(3)The factors driving the change of landscape pattern in Tianjin mainly include population,socio-economic development,composition of local industrial structure and agricultural development level.The driving force of landscape pattern change has shown an upward trend in the past two decades,and the comprehensive score of driving factors has increased from-1.27 to 0.215.There are differences among districts and counties,but it is similar to Tianjin as a whole.(4)From 2000 to 2020,the eco-environmental quality index of Tianjin showed a fluctuating growth,which decreased first and then increased,from 0.35 in 2000 to 0.32 in 2015,and rebounded to 0.34 in 2020;In terms of the contribution rate of ecoenvironmental quality change,the conversion of water area land into construction land has the highest contribution rate of eco-environmental deterioration of 0.0341,and the conversion of cultivated land into water area land has the highest contribution rate of eco-environmental optimization of 0.1005.(5)Based on the above analysis,some suggestions are put forward for the future development of Tianjin,such as improving the land use monitoring and management mechanism,strictly reviewing the transformation of various land use types,improving land use planning and land use zoning construction. |
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