Spatiotemporal Evolution And Transmission Effects Of Land Pressure In The Yangtze River Delta Region

Land is an essential material foundation for human life and development,as well as an irreplaceable means of production for human survival.However,the rapid economic and social development has brought enormous pressure on land resources,and as the human demand for land resources is increasing,the conflict between humans and land is gradually emerging and intensifying.The imbalance between the scarcity of land resources and social development demands is progressively becoming a major impediment to regional sustainable development.It is critical to perform research on land pressure in the Yangtze River Delta region to reconcile the conflicts between human activities and land in the region and establish a win-win scenario between economic growth and sustainable use of land resources.This thesis integrates multi-source and multi-scale data to investigate 41 cities in the Yangtze River Delta region.Firstly,a land pressure evaluation method system is systematically created based on the perspective of land production-living-ecology to analyze the total level of land pressure at 1km grid resolution in the Yangtze River Delta region in 1995,2000,2005,2010,2015,and 2020 and reveal the spatial and temporal evolution characteristics of land pressure over 25 years in the Yangtze River Delta region.On this basis,a mechanistic equilibrium model was used to investigate the trade-offs and synergies among land production,living,and ecology pressure,identify regions of dysregulation in land production,living,and ecology pressure,and offer differential regulation strategies.To further explore the effects of land pressure drivers,a center of gravity-GTWR model was established to clarify the degree of contribution of each factor.Finally,to explore the land pressure transmission effects in the Yangtze River Delta region and identify the land pressure transmission paths,a spatial correlation network of land pressure was constructed based on the modified gravitational model,and its structural characteristics were analyzed using the social network analysis method.The following are the key findings and conclusions:(1)The land pressure evaluation method system was built based on the perspective of land production-living-ecology.On the basis of clarifying the connotation characteristics of land pressure and the interactions among land production,living,and ecology pressure,the land pressure evaluation method system was systematically established from the perspectives of land production,living,and ecology pressure integrating the grid scale and administrative district scale.This thesis tested the land pressure evaluation method using Monte Carlo simulation to clarify the reliability and validity of the land pressure evaluation results.The test results demonstrated that the land pressure evaluation results are extremely reliable and that the land pressure evaluation method can accurately reflect the land pressure level in the Yangtze River Delta region.(2)The spatial and temporal evolution characteristics of land pressure in the Yangtze River Delta region were revealed based on the land pressure evaluation system.According to the findings,land pressure in the Yangtze River Delta region is spatially distributed as follows:"high in the east and low in the west,high in the south and low in the north".The level of land production pressure is trending downward,the level of land living and ecology pressure is trending upward,and the spatial distribution of land production pressure and spatial distribution of land pressure are still consistent.Land living pressure is greater in the southeast and provincial capitals and lower in the northwest,while land ecology pressure varies from high in the northwest and central-east to typically higher in the north than in the south.The coordination level of land production,living,and ecology pressure grew from 9.68 to11.77,and it varied between abrasion and antagonistic.The incompatibility between land production,living,and ecology pressure is gradually increasing,mainly in the form of coordination,abrasion,and antagonism to dysregulation,with the proportion of synergistic areas decreasing from 70.34%to 49.73%and the proportion of trade-off areas increasing from 29.66%to 50.27%.The spatial units with varying coordination levels exhibit various features,and antagonistic and dysregulated type areas are mostly found in southern Anhui Province,southern Jiangsu Province,and the majority of Zhejiang Province.(3)The divergent pattern of land pressure drivers in the Yangtze River Delta region was clarified based on the center of gravity-GTWR model.First,a comparison of various models revealed that the R~2 of the center of gravity-GTWR model is 0.96,which is greater than the R~2 of other regression analysis models,demonstrating the feasibility of the center of gravity-GTWR model in the analysis of land pressure drivers in the Yangtze River Delta region and optimizing the method for analyzing land pressure drivers.Next,the study found that the center of gravity of built-up land in the Yangtze River Delta region is gradually shifting to the southeast region where economic development is faster.The drivers of urban spatial expansion,population status,economic development scale,population consumption level,and ecology status influence land pressure in the Yangtze River Delta region with significant spatial and temporal heterogeneity and the intensity and direction of their effects vary from city to city.(4)To reveal the transmission effect of land pressure,a spatial correlation network analysis method was constructed.It was found that the network density of land pressure in the Yangtze River Delta region decreased by 5.97%,network efficiency increased by 6.21%,network correlation remained at 1,and network efficiency remained at 0,indicating that the spatial correlation structure of land pressure in the Yangtze River Delta region is relatively stable and balanced in development,but regional coordination still needs to be improved.It is crucial to consider the prominent bridging functions of Nanjing,Shanghai,Suzhou,Hangzhou,and Changzhou as node cities when establishing a land pressure relief mechanism to reduce land pressure from a more comprehensive regional synergy.The eastern cities of the Yangtze River Delta region absorbed resources from the other cities to meet their own needs.The southern cities relieved the land pressure of the other cities through the overflow of resource elements.The Yangtze River Delta region’s western and northern cities acted as bridges in the spatially linked network of land pressure,facilitating the flow of resource elements and inter-city exchanges and cooperation.The geographical boundaries were disrupted by the Yangtze River Delta region’s transmission effect of land pressure,demonstrating the extension from the coast to the inland,transmission from developed cities to less developed cities,the trend of spreading from central cities to the periphery,and hierarchical transmission characteristics.There are 54 figures,26 tables,and 312 references in this thesis.