Evaluation Of The Ecological Effects Of The Expansion Of Construction Land In Rapid Urbanization Areas

The development of urbanization represents the improvement of the level of productivity and the transformation of people's production organization,and is a important way for the development of human society.In recent years,China's urbanization process has been accelerating,and the environmental problems caught by it have seriously affected people's health and life.With the advancement of urbanization,changes in land use structure have also had a huge impact on the ecological environment.This paper takes Tianjin as the research object,and analyzes the three dimensions of population urbanization,land urbanization and economic urbanization.The urbanization level of household registration increasing by more than 2.5 percentage points per year,the urbanization rate more than 45%,the average annual growth rate of construction land more than 3%and the economic growth rate more than 10%per year are defined indicators of rapid urbanization areas.After comprehensive comparison,Dongli District was selected as the representative for further research.This paper uses the urban land expansion coefficient,construction land index and urban expansion intensity metrics to judge the rationality,regional development level and development speed of Dongli District.The ecosystem service value equivalent factor table is used to calculate the change of ecosystem service value in Dongli District.Through comparing the factors of urbanization development,the stress and coordination effects of construction land expansion and other factors on the ecological environment are analyzed,and effective coordination countermeasures are proposed.The research results show that the urban land expansion coefficient of Dongli District is 0.58,the urban expansion speed is extremely unreasonable,and the population and land urbanization are not coordinated.In 2005-2010,Dongli District is in the high-speed period of construction land growth,and its expanded spatial characteristic of construction land is presented as "circle layer".This expansion is affected by the urban center of Tianjin and the main ur'ban area of Binhai New Area.The driving force for the expansion of construction land is affected by nature,policy,economy,population,transportation and other factors.The ecological land in Dongli District decreased from 111.6 km2 in 2005 to 82.6 km2 in 2015,with a decrease of 25.0%.The per capita ecological land decreased from 214.1 m2 in 2005 to 109.7 m2 in 2015.The total value of ecological services was decrease from 104,138,600 yuan in 2005 to 685,585,200 yuan in 2015,with a decrease of 3,576,024 yuan and the average annual reduction rate of 4.1 1%.For an increase of 1km2 in construction land in Dongli District,the value of ecosystem services will be reduced by 4,076,700 yuan.It can be seen from the results that the changes in the ecological environment are closely related to the development of urbanization.As long as we start with the coupling relationship between them and take corresponding measures,the environmental problems brought about by regional development may be improved.