Research On The Impact Of Land Use Change On Urban Ecological Carrying Capacity In The Era Of Urbanization

Nowadays,the world is in the wave of urbanization.High-speed and large-scale urbanization has brought about drastic land use changes,aggravated environmental pollution,tighter resource constraints and other problems,which triggers a crisis of urban ecological carrying capacity(UECC).If these problems could not be identified and solved,the urban sustainable development mission cannot be achieved.In the era of China’s new urbanization and ecological civilization,it is particularly urgent and important to examine the impact of land use change on UECC.However,it seems little attention has been paid to investigate the relationship between land use chage and ecological carrying capacity.Under such circumstance,this paper aims to conduct a research on the impact of land use change on UECC along the road map of "problem raising-theoretical analysis-methodology establishment-empirical study-problem solving".This paper mainly contains the following research contents: 1)Discriminating the connotation of land use change from a multi-dimensional perspective,redefining UECC based on the interaction between the carriers and loads in an urban ecosystem,and analysising the impact mechanism of land use change on UECC.2)Establishing a method for measuring land use change,constructing a model for UECC combined with the net primary Productivity and the In VEST model,and establishing a model to examine the impact of land use change on UECC based on GTWR.3)An empirical case study has been conducted based on the data collected in Chongqing’s from 2010 to 2018 under the5km×5km scale;4)Formulating measures to improve UECC through optimizing land use pattern.This paper mainly draws the following research conclusions: 1)Land use change affects the UECC by changing carrier and load factors in an urban ecosystem and these effects are double-edged.2)From the "direction-speed-pattern" multi-dimensional perspective,land use change can be measured comprehensively and systematically,and the UECC measurement model supports the calculation of high-precision and long-term series;and the GTWR model for examing the impact of land use change on urban ecological carrying capacity can reflect the temporal and spatial instability of the impact effect.3)During the empirical period,the main direction of land use change in Chongqing was arable land to forest,grassland to forest,and cultivated land to construction land,and the overall rate of change has slowed down,and the spatial-temporal differences of land use pattern change were obvious.4)The ecological carrying capacity of Chongqing showed a trend of decreasing at first and then increasing,and the main urban area showed a downward trend but the speed slowed down;Spatially,the overall performance of ecological carrying capacity in the southeast of Chongqing is better than that in the northwest,and the low-value areas of ecological carrying capacity continue to expand around the core urban areas.5)The change direction of cultivated land to forest land has the most significant positive impact on UECC,while the forest to construction land and cultivated land to construction land have obvious negative impact.The effect of land use change rate on UECC changed from negative effect to positive effect from 2010 to 2018 in Chongqing.The change of land use pattern has a dynamic influence on UECC with both positive and negative effects.6)The land use pattern should be optimized from the three-dimensional perspective of "direction-speed-pattern" to improve UECC.As for Chongqing,in terms of direction adjustment,it advocates to promote the conversion of farmland to forest,and strictly controls the occupation of cultivated land and woodland by construction land.In terms of speed controllment,it is suggested to implement the differential control measures of “encouraging”" and “limiting”.In terms of the pattern optimization,it is suggested to controll the disorderly expansion of construction land in the main urban area,and enhance the connectivity of ecological units in the ecological conservation functional area in Northeast Chongqing.Theoretically,this paper analyzes the impact mechanism of land use change on UECC and constructs a theoretical method to measure the effect,which makes up for the current lack of researches on the impact of land use change on UECC,which provides a new research perspective and research paradigm for exploring the ecological effects of land use in the context of urbanization.Practically,the results of this paper is helpful to understand the impact of land use change on UECC.The results of this paper also can provide references for land management and utilization in Chongqing and other citiesm so as to formulate effective measures to reduce the negative impact of urbanization on the ecological carrying capacity and promote urban sustainable development effectively.