Temporal And Spatial Evolution Of Land Use Conflicts In The Poverty Belt Around Beijing And Tianjin From The Perspective Of Ecological Security

Land use conflict is one of the important frontier issues in the field of land science. With the rapid development of urbanization and industrialization process, the dramatic changes of land use pattern have occurred in the past three decades in China. There were a lot of contradictions between human society and natural physical ecosystem, which were presented as land use conflicts. The sustainable development of economy and society and regional ecological security were facing severe challenges,and land use conflict was becoming more and more serious. How to deal with land use conflicts has become an urgent problem in many fields, such as land use, land resources management, ecological protection and so on. Mitigating land use conflicts was effective and essential to improve the sustainability of economic and ecological system. Based on the practical needs of ecological security and the coordinated development of ecology and economy, the concept and connotation of land use conflict was defined from the perspective of ecological security. Then, based on the related theories and methods of ecology, geography, land science and other disciplines, a method system of identification, classification and intensity measurement of land use conflict was built from the perspective of ecological security. The poverty belt around Beijing and Tianjin was selected as case study area, and multi-methods and multi-source data were used to explore the temporal and spatial evolution of land use conflict and its driving mechanism, and simulate the spatial pattern of land use conflict under different scenarios in the future. The data used in this study covered remote sensing image, meteorological observation data, statistical material and field survey data. The methods used in this study included mathematical statistic method, spatial analysis based on GIS, spatial econometric model, geographical weighted regression (GWR), minimum cumulative resistance (MCR)model and Markov- CLUE-S Models. The purpose of this study is to explore how to identify and measure land use conflicts, and investigate the spatial pattern of land use conflicts and their driving factors. The main results are as follows:(1) The concept and connotation of land use conflict were defined from the perspective of ecological security. Under the perspective of ecological security, land use conflict can be defined as the occupation of ecological security space by human economic activities including agricultural cultivation, economic construction, which was mainly manifested in the disharmonious spatial relationship of the competition and contradiction between the spatial pattern of cultivated land and construction land and the space of ecological security, namely the spatial mismatch overlap between the space of cultivated land, construction land and the space of ecological security. The ecological security space refers to the areas that provide important ecological functions such as water conservation, soil conservation, prevention of wind and sand fixation and biodiversity protection, with special sensitivity or potential natural calamity to external interference, which are easily affected by human activities and produces negative ecological effects. It can be divided into different levels according to the sensitivity degree to human development and interference.(2) Evaluate the spatial pattern of ecosystem service function and then identify the land use conflicts in the poverty belt around Beijing and Tianjin. According to the spatial plan and physic-geographical environment, water conservation, soil conservation, windbreak and sand fixation and biodiversity conservation are selected as the key ecosystem service functions. Then using the model of CASA, RUSLE,RWEQ and In VEST to evaluate the aforementioned ecosystem service function, combine them together to generate a layer of ecosystem service function importance and divide it them into 5 ranks. Following that,the sensitivity of soil erosion and geologic hazard are also evaluated and divide into 5 ranks: Next, combine the layer of ecosystem service function importance and the layer of ecological sensitivity, and select the highest rank of them as the ecological source area needed to be conserved. Then evaluate the ecological security by minimum cumulative resistance model to create a layer of ecological security. Finally, the land use conflicts can be measured by weighted summing the share of farmland and constructive land locating in region with different ranks of ecological security at the level of county, fishnet of 3km×3km and grid.(3) The methods of mathematical statistics, spatial analysis, spatial econometric models and minimum cumulative resistance (MCR) model were used to analyze the spatio-temporal evolution of land use conflict and its driving mechanism in the poverty belt of Beijing and Tianjin. The results showed that the characteristics of spatial and temporal differentiation of land use conflict were significant in the period of 1985-2015 in the the poverty belt around Beijing and Tianjin. From the perspective of types of land use conflicts, the area of cultivated land conflict increased first and then decreased during 1985-2015. The type of very serious and serious cultivated land conflict were mainly distributed in Bashang Plateau and the west of Zhangjiakou city, as well as the east of Chengde city, which mainly referred to Zhangbei, Guyuan,Huai'an,Yangyuan,Yuxian County, Wanquan,Pingquan and Chengde County. The area of construction land conflict increased continually during 1985-2015. The distribution of very serious conflict in construction land was scattered, which was distributed in each county and district. Serious and lower serious conflict in construction land were mainly distributed in the west of Zhangjiakou and the south of Chengde. From the aspect of land use conflict intensity, the conflict intensity of cultivated land increased first and then decreased during 1985-2015. From the aspect of the terrain gradient characteristics of land use conflict, the terrain gradient pattern of cultivated land conflict was similar to cultivated land conflict during 1985-2015. The very serious and serious conflict in cultivated land and construction land were mainly distributed in the low terrain gradient zone. The conflict intensity of cultivated land and construction land were significant difference in this terrain gradient zone.(4) The dynamic of spatial pattern of land use conflicts are driven collectively by the forces from natural geographic environment, social economic and policies. At the fishnet level, terrain and location are the key affecting the distribution of land use conflicts. The land use conflict is significantly and negatively associated with terrain niche index, distance to river, distance to major road, distance to building area of county and distance to town building area. At the county level, social economic factors and policies play key roles. The factors have impacts on distribution of cropland use conflicts include share of land irrigated effectively, rate of natural disaster, population density, economic density, and urbanization, share of secondary and tertiary industries, per capita income of farmers, afforestation area, area of grain for green project. The factors have impacts on distribution of constructive land use conflicts include population density, economic density, urbanization, fixed assets investment, per capita income of farmers, road network density, area of grain for green project, and number of policy types.(5) The land use simulation of four scenarios (namely, land use planning scenario, natural development scenario, ecological-oriented scenario, and farmland protection scenario) were designed according to the actual conditions of the poverty belt around Beijign and Tianjin. The model of Markov-CLUE-S were used to simulate the spatial pattern of land use conflict under different scenarios in the future. The results showed that different land use scenarios were suitable for different districts and counties. Land use planning scenario was suitable for Chongli county, and farmland protection scenario was suitable for Yuxian county, and ecological-oriented scenario was suitable for the other districts and counties of Zhangjiakou. The ideal land use scenario was different in different terrain gradient zone. The land use planning scenario was suitable for the 1-5th level terrain gradient zone, and the natural development scenario was suitable for the area of 5-10th level terrain gradient zone. There is no obvious difference in the intensity of land use conflict under the four land use scenarios in the area of 11-15th level terrain gradient zone.This thesis researched on land use conflict in the poverty belt around Beijing and Tianjin at the scale of grid, fishnet, and county administrative unit from the perspective of ecological security. This study realized quantitative, location-based and precise research on land use conflict. This study not only can provide a scientific basis for land use management and ecological infrastructure construction, but also can provide a typical regional case for the global land research plan, which will help to enrich and expand the research content and application scope of land change science.