Research On Coordinated Development Of Urbanization Based On Land Ecological Sensitivity

Among the many problems of global Change,Land Use/Cover Change(LUCC)has increasingly become the core field of global environmental change research.LUCC can cause changes in many natural phenomena and ecological processes,such as soil erosion,surface runoff,soil nutrient and water changes,etc.The study of the relationship between LUCC and soil has gradually become a new and important topic in the study of LUCC and land degradation.Urbanization is the main content of LUCC research.Regional natural conditions are an important factor affecting the land condition,but with the increase of human activities,the regional topographic conditions change,soil characteristics deteriorate,vegetation resources are destroyed,thus aggravating soil erosion.The intensification of soil erosion,in turn,restricts the way and structure of land use,leads to the degradation of land productivity,further intensifies the contradiction between man and land,and restricts the sustainable development of cities.In China,the rapid economic growth,the acceleration of urbanization and the huge population base all aggravate the land degradation related to soil erosion,which is the focus of the international community at present.China is one of the regions with the largest and most serious soil erosion.Therefore,how to coordinate the relationship between economic growth and land ecological environment is one of the urgent problems.Ganjiang Valley is one of the main tributaries of Yangtze River and an important area for the development of economy and culture in our country.The main soil type is red soil with high erodibility.It is a typical red soil hilly distribution area in southern China.With the development of new urbanization,land degradation is becoming more and more serious.Therefore,it is necessary to further study the coupling and coordination relationship between urbanization and land degradation,which is conducive to the improvement of regional ecological environment and sustainable urban development.Based on the theories of management,ecology,human geography,regional economics and other relevant disciplines,this paper starts with the discussion of man-land relationship in the basin,carries out an empirical study on the basin land ecosystem,and puts forward management and control plans for the future sustainable development of the basin.In this paper,the Ganjiang River Basin with typical red soil in the Yangtze River Basin was selected as the research area to study the response relationship of urbanization to land degradation pattern at the basin scale.On the basis of high-precision spatial characterization of basin land degradation pattern and identification of erosion hotspots,the mechanism of basin urbanization and land degradation is discussed to construct a regulation and management system for coordinated development of urbanization at the basin scale,and formulate basin land use and protection policies for theoretical and data support.Based on remote sensing image data of Ganjiang River basin in 2000,2005,2010,2015 and 2020,GIS technology was used to provide data support for analysis.The general soil loss equation(RUSLE)was introduced to calculate the intensity of soil erosion and the evolution of spatial pattern in the basin.Land degradation hotspots were identified by land ecological sensitivity assessment.Then,the coupling coordination degree model(CCDM)was used to study the interaction stress relationship between basin urbanization and land ecological sensitivity assessment(ESA),and the dynamic simulation and prediction of urbanization and soil and water loss were carried out by establishing the system dynamics model.After that,the paper simulates the urban development pattern of Ganjiang River Basin in order to provide reference for the implementation of land ecological protection and the formulation of urban sustainable development strategy in the future.The following research results were obtained:(1)Soil erosion intensity in the Ganjiang River Basin was calculated based on the modified general soil erosion model,and the evolution of spatial pattern was analyzed.Based on the technical support of Remote Sensing,Globe Position System and Geographic Information System,The RUSLE soil erosion model based on ArcGIS 10.0 was used to obtain the soil erosion amount of Ganjiang River Basin in different periods and different land use patterns.The change of land use mode and its characteristics in the basin during the 20 years were analyzed,and the change law of soil erosion in different periods of the basin was simulated.The influence of the change of land use mode on soil erosion in the basin was emphatically discussed,in order to provide scientific guidance for the optimal allocation of land resources and effective control of soil erosion in the Ganjiang River basin.In 2000,2005,2010,2015 and 2020,the soil erosion of Ganjiang River Basin was 8.57×10~7,1.27×10~8,1.51×10~8,1.47×10~8 and 1.24×10~8t.2000,2005,2010,2015 and 2020,average in ganjiang river basin soil erosion modulus were 1026.80,1519.31,1803.78,1759.15,and 1479.84 t/(km~2a).The soil erosion modulus of Ganjiang River Basin increased by47.96%during 2000-2005.From 2005 to 2010,the soil erosion modulus of Ganjiang River Basin increased by 18.72%.From 2010 to 2015,the soil erosion modulus of Ganjiang River Basin decreased by 2.47%.The soil erosion modulus of Ganjiang River Basin from 2015 to 2020 was 15.88%.From 2000 to 2020,the soil erosion modulus of Ganjiang River Basin increased by 44.12%.On the whole,soil erosion in Ganjiang River Basin has been intensified.(2)The coupling coordination degree model was used to measure the coordination relationship between urbanization and land ecological sensitivity in the Ganjiang River Basin from 2000 to 2020.The coupling coordination index of urbanization and land sensitivity evaluation in Ganjiang River Basin showed a spatial distribution pattern of high in the east and low in the west,high in the north and low in the south.The results show that:The overall degree of urbanization in the Ganjiang River Basin is highly consistent with the spatial distribution pattern of land degradation.The high-high coupling aggregation is concentrated in the northwest of Jiangxi,while the low-low coupling aggregation is concentrated in the southeast of Jiangxi,showing a pattern of"high northwest and low southeast".The coupling evolution of Ganjiang River Basin urbanization and land ecosystem is complex,and the synergistic development of urbanization development level and land degradation shows a"U"shape in the time series,which is consistent with the development law of environmental Kuznets curve(EKC).The spatial difference of urban land degradation in the Ganjiang River Basin is decreasing gradually.There is a significant spatial autocorrelation of urban land degradation,and the urban land degradation in the Ganjiang River Basin shows a weakening trend of spatial agglomeration.From 2015to 2020,with the effective regulation of urban land expansion,Ganjiang River Basin has gradually shifted to the mode of land intensive and ecological protection.(3)The Defense Meteorological Satellite Program(DMSP)/Operational Line-Scan System(OLS)night light data were used to identify the urban core and marginal areas in the Ganjiang River basin.Taking the urban core area and urban fringe area of the Ganjiang River basin as the research object,an index was constructed to measure the level of urbanization land degradation,and the spatio-temporal variation characteristics and change mechanism of land sensitivity in the core area and urban fringe area of the Ganjiang River basin were discussed.The results show that:From 2000 to 2020,the land degradation probability of rapidly urbanized areas in the lower reaches of Ganjiang River Basin is relatively high;However,some rapidly urbanizing areas in other regions have not experienced such severe land degradation.Urbanization does not necessarily lead to large-scale land degradation.The driving mechanism of land degradation in urbanization is spatio-temporal non-stationary.During the study period,as urban area,road density,slope,and population density increased,the urban periphery expanded into highly sensitive land and land degradation decreased(reflecting,in terms of land degradation,a more sustainable pattern of urbanization);As the distance from adjacent urban centers increases,land degradation increases,and the urban periphery expands to better land.The compact development model of spatial coordination of rural planning has proved to be an appropriate strategy for coping with land degradation.In the future urban construction of Ganjiang River basin,according to the requirements of green development,the function of old city and reasonable compact type should be strengthened to promote the use of urban land.The towns and cities in the Ganjiang River basin should adhere to the transformation of the economic system,adjust the industrial distribution,and shift the focus of development from quantity and quantity to development.(4)The coupling between regional urbanization and land ecological environment was simulated by system dynamics method,and different sustainable development scenarios were compared.The system dynamics model integrates human and nature elements,including five sub-models:economy,population,water,food and land.The model can identify the optimal sustainable regional development model by feedback recognition to represent the nonlinear interaction between submodels.The results show that:giving priority to urbanization will accelerate economic growth and increase the area of soil erosion.Putting land ecological environment in the first place will have a negative impact on population and cultivated land.With policy and technical support,urbanization will not further deteriorate the land ecological environment.Four schemes reflecting the needs of sustainable development are constructed.The simulation results of different scenarios show that the key to ensure sustainable development of the basin is to improve the level of land governance and financial policy support,rather than further restrict urbanization.The model is of great significance for improving sustainable regional development planning.(5)Based on the land use change pattern and ecological sensitivity of Ganjiang River Basin in the next 20 years,the future urban development pattern of Ganjiang River Basin is simulated.After land sensitivity was incorporated into the simulation system as a driving force in Markov-FLUS model,the land use prediction of Ganjiang River Basin has a high accuracy,and can better fit the future land use pattern of Ganjiang River Basin in 2030.System verification shows that the total accuracy of FLUS model reaches 93.75%and Kappa coefficient is 0.8796,much higher than 0.8.The future land use prediction of Ganjiang River Basin can use this model.