随着我国城镇化速度的加快，人口数量增加和城市规模扩张使区域生态环境受到强烈的人为干扰，其中不合理的土地资源利用方式严重影响着区域生态的稳定性。景观生态风险评价是以土地利用景观作为风险评价综合体，通过构建模型并计算风险指数评价区域内景观生态风险变化特征，从而反映人类活动对生态环境造成的影响。因此，基于土地利用变化进行景观生态风险评价研究，对区域合理配置土地资源、生态环境保护及促进资源可持续利用具有重要的现实意义。

本文以西安市为研究区域，基于土地利用数据对研究区土地利用时空变化、景观格局空间异质性特征进行分析；在此基础上，选取适当的景观指数构建景观生态风险评价模型，对西安市1990-2018年四个时期的景观生态风险时空变化特征进行分析，并探究西安市景观生态风险动态变化的主要驱动力。论文主要研究内容及结论如下：

（1）基于土地利用数据，采用土地利用动态度、土地利用转移矩阵等方法分析研究区土地利用时空变化特征，并利用景观指数和移动窗口法对研究区景观格局空间异质性特征进行分析。结果表明：1990-2018年间耕地、草地和水域的面积呈减少趋势，分别减少565.842km²、138.797km²、6.079km²，建设用地、林地和未利用地的面积呈增加趋势，分别增加621.786km²、87.971km²、0.18km²，其中耕地和林地始终是西安市优势土地利用类型。单一动态度中建设用地变化速度最快，最高达3.37%，综合动态度的变化速度随时间推移而持续增加，最高达10.23%。耕地面积转出和建设用地面积转入是西安市土地利用变化的主要形式。景观格局空间异质性分析中各指数均表现出较显著的变化特征，表明各土地利用类型变化与生态效应之间具有明显的关联性。

（2）基于景观格局的方法选取景观干扰度、景观脆弱度、景观损失度等指数构建景观生态风险评价模型，对1990-2018年西安市景观生态风险时空变化特征进行分析，并利用空间自相关模型探究其空间自相关性和异质性。结果表明：1990-2018年西安市景观生态风险等级的空间分布特征表现为东部高于西部、北部高于南部，整体上生态风险处于中等风险等级水平，整体风险指数由0.6935降为0.6753，下降幅度为2.6%，且随时间推移呈持续递减趋势。在面积变化上，高和较高生态风险区呈减少趋势，中等生态风险区为先增加后减少，低和较低生态风险区为增加趋势，其中高生态风险区面积减少440.48km²，低生态风险区增加271.32km²；各生态风险等级的转移速率中，高和较高转出速率较大，低和较低转入速率逐年递增，而中等风险区变化因易受人为干扰的影响，转移速率不稳定。综合以上分析，西安市生态风险状况处于良性的发展趋势。在空间自相关分析中，四个时期中全局自相关指数值均在0.55左右，表明研究区景观生态风险值在空间上具有显著的正相关性；局部自相关显示生态风险空间分布以“高-高”和“低-低”聚集为主，具有明显的“同质集聚、异质分离”的特征。

（3）基于多角度探究西安市景观生态风险动态变化的影响因素及其驱动力，先从自然因素和人为因素两个角度进行生态风险响应分析；然后基于地理探测器模型，选用因子和交互两种探测器定量分析动态变化的主要驱动力。结果表明：生态风险响应分析中，自然因素对生态风险动态变化具有控制作用，而人为因素是推动其动态变化的主要影响因素；因子探测器结果显示，人为干扰度和高程对生态风险动态变化的解释力最大，分别为51.14%和25.24%；交互探测器结果显示，任何两种影响因子的交互对生态风险动态变化的解释力均存在协同增强的作用，其中各类因子在与人为干扰度因子交互后，对生态风险动态变化的解释力均有较大提升。综合分析，在单因子中人为干扰度对生态风险动态变化的解释力最大；交互作用中人为干扰度与地形因素的交互是西安市景观生态风险动态变化的主要驱动力。

With the acceleration of my country's urbanization, the increase in population and the expansion of urban scale have caused strong human disturbance to the regional ecological environment. Among them, the unreasonable use of land resources seriously affects the stability of regional ecology. Landscape ecological risk assessment is based on the land-use landscape as a risk assessment complex. By constructing a model and calculating a risk index, the characteristics of landscape ecological risk changes in the assessment area are evaluated to reflect the impact of human activities on the ecological environment. Therefore, the study of landscape ecological risk assessment based on land use change has important practical significance for the rational allocation of land resources, ecological environment protection and promotion of sustainable use of resources.

Taking Xi’an as the research area, this paper analyzes the spatial and temporal changes of land use and the spatial heterogeneity of landscape patterns in the study area based on land use data. On this basis, a landscape ecological risk evaluation model was constructed by selecting appropriate landscape indices, analyzing the characteristics of spatial and temporal changes in landscape ecological risk in Xi'an over four periods from 1990 to 2018, and exploring the main drivers of dynamic changes in landscape ecological risk in Xi'an. The main research contents and conclusions of the thesis are as follows:

(1) Based on land use data, analyze the spatiotemporal characteristics of land use change in the study area using methods such as land use dynamics and land use transfer matrix, and analyze the spatial heterogeneity of landscape pattern in the study area using landscape index and moving window method. The results show that the area of cultivated land, grassland, and waters showed a decreasing trend from 1990 to 2018, decreasing by 565.842km², 138.797km², and 6.079km² respectively. The area of construction land, woodland and unused land showed an increasing trend, increasing by 621.786km², 87.971km², and 0.18km² respectively, but cultivated land and woodland are always the dominant land use types in Xi’an. Among the single dynamics, the construction land changes the fastest, up to 3.37%, and the change speed of the comprehensive dynamics continues to increase over time, up to 10.23%. The transfer of cultivated land area and the transfer of construction land area are the main forms of land use change in Xi'an. In the analysis of the spatial heterogeneity of landscape pattern, each index showed significant change characteristics, indicating that there is a clear correlation between changes in land use types and ecological effects.

(2) Based on the method of landscape pattern, the index of landscape disturbance, landscape vulnerability, landscape loss, etc. was selected to construct a landscape ecological risk assessment model, and the characteristics of the spatial and temporal changes of landscape ecological risk in Xi’an from 1990 to 2018 were analyzed, and the spatial autocorrelation model was used to explore it Spatial autocorrelation and heterogeneity. The results show that the spatial distribution characteristics of landscape ecological risk levels in Xi’an from 1990 to 2018 are higher in the east than in the west and higher in the north than in the south. The overall ecological risk is at a medium risk level, and the overall risk index is reduced from 0.6935 to 0.6753, a decrease It was 2.6%, and showed a continuous decreasing trend over time. In terms of area changes, high and high ecological risk areas showed a decreasing trend, medium ecological risk areas increased first and then decreased, and low and low ecological risk areas showed an increasing trend. Among them, the area of high ecological risk areas decreased by 440.48km² and low ecological risk areas. Area increase by 271.32km²; Among the transfer rates of each ecological risk level, the high and high transfer rates are larger, the low and low transfer rates increase year by year, and the changes in the medium risk area are susceptible to human disturbance and the transfer rate is unstable. Based on the above analysis, the ecological risk status of Xi'an is in a benign development trend. In the spatial autocorrelation analysis, the global autocorrelation index is around 0.55 for the four periods, indicating that the landscape ecological risk value of the study area has a significant positive correlation in space; The local autocorrelation shows that the spatial distribution of ecological risk is dominated by “high-high” and “low-low” aggregation, with obvious characteristics of "homogeneous aggregation and heterogeneous separation".

(3) Exploring the influencing factors and driving forces of the dynamic changes of landscape ecological risk in Xi'an from multiple angles, and firstly analyze the ecological risk response from the perspectives of natural factors and human factors; then, based on the geographic detector model, select factor and interactive detectors quantitatively analyze the main driving forces of dynamic changes. The results show that in the analysis of ecological risk response, natural factors have a controlling effect on the dynamic changes of ecological risks, and human factors are the main influencing factors to promote its dynamic changes; the results of the factor detector show that the degree of human disturbance and elevation have the greatest explanatory power for the dynamic changes of ecological risks, which are 51.14% and 25.24%, respectively; The results of the interaction detector show that the interaction of any two influencing factors has a synergistic effect on the explanatory power of the dynamic changes of ecological risks. Among them, all kinds of factors have the same explanatory power on the dynamic changes of ecological risks after interacting with the human disturbance factor. There is a big improvement. Comprehensive analysis shows that the degree of human disturbance has the greatest explanatory power for the dynamic changes of ecological risk among the single factors; the interaction between the degree of human disturbance and topographic factors in the interaction is the main driving force for the dynamic changes of landscape ecological risk in Xi'an.

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