Study Of The Ecological Environment Effect On Construction Land Spatial Expansion In Shijiazhuang

Since the reform and opening up,the urbanization process has been increasing gradually,and the rapid expansion of urban construction land is regarded as one of the most obvious characteristics of urbanization.However,throughout the history of China's urban growth planning,the research period of urban construction land spatial expansion is relatively short,and the theory is still improving,and the mode of construction land expansion is mostly "incremental marginal" mode.This mode of construction land expansion,usually at the expense of ecological land and agricultural land around the city,will cause irreversible damage to the ecological environment.As the basis of human social activities in cities,the decline of ecological environment quality will not only reduce the livability of cities,but also threaten human life and health.Therefore,it is very important to clearly understand the spatial expansion mode of urban construction land and its ecological environment effect.In this paper,the urban area of Shijiazhuang and the adjacent key development counties(Zhengding County)in the north are selected as the research areas.The clear and cloudless Landsat images in the summer of 1979,1988,1998,2009 and 2019(May-August)are selected as the research data,supported by sustainable development theory,system theory,human land relationship theory and ecological economics theory,based on envi 5.3 and Arc GIS 10.5 statistical analysis platform,using single window algorithm,ecosystem service value estimation model and RS and GIS spatial analysis method,two research contents are discussed in depth:(1)identify and extract the construction land patches in Shijiazhuang City,characterize the scale and area of construction land in Shijiazhuang City,and then select relevant index model to expand the construction land space in Shijiazhuang city Quantitative analysis of changes and ecological land transfer analysis;(2)analysis of the thermal effect changes and the spatial and temporal changes of ecosystem service value in the process of construction land expansion in Shijiazhuang City in the past 40 years,and a detailed analysis of the relationship between construction land expansion and ecological environment effect in Shijiazhuang city.The main conclusions of this paper are as follows:(1)from 1979 to 2019,the area of construction land in Shijiazhuang city expanded obviously,and the area of construction land in Shijiazhuang City Center expanded year by year,and gradually connected to the surrounding areas.Based on the anisotropy of the expansion scale,it is found that the expansion of construction land in Shijiazhuang to the East is obvious in the past 40 years,but the anisotropy of the expansion dynamic degree in each direction is not obvious.In the sixteen expansion directions,the eastern region has the largest contribution rate;(2)from the perspective of the transfer relationship between construction land and ecological land,the main transfer source of construction land is cultivated land.From the perspective of the transfer out relationship,the cultivated land area gradually decreased,and more than 75% of the reduced area flowed to the construction land;(3)the thermal effect range of Shijiazhuang City showed a trend of "first decreased then increased" in 1988-2019.Comparatively speaking,the ecosystem service value of Shijiazhuang has declined steadily in the past 40 years.The results show that the trend line of construction land expansion intensity index is in direct proportion to the trend line of thermal effect and in inverse proportion to the trend line of ecosystem service value.