【作者】 刘莉莉；

【导师】 杨瑾；

【作者基本信息】 长安大学 ， 土地工程学， 2024， 硕士

【摘要】 生态安全是国家安全体系的重要基石,对区域生态环境进行及时评价并根据区域实际情况构建生态安全格局,是实现生态安全的基础。咸阳市是黄河流域生态安全屏障格局的中心地带,生态区位重要,本文通过对咸阳市土地生态安全变化及生态安全格局构建进行研究,旨在推进咸阳市生态环境持续好转,平衡区域发展与保护。首先从咸阳市土地利用变化情况出发,根据2000、2010及2020年三期土地利用数据,结合土地利用动态度和转移矩阵,分析各地类的规模变化和转移情况;其次基于人类活动压力、土地状态变化以及管理决策响应三者之间的相互作用关系,采用PSR模型构建评价指标体系,分析PSR三大要素和整体土地生态安全变化情况;然后为了缓解景观破碎问题,加强生态空间联系,采用MCR模型提取并补充生态廊道,识别生态节点,构建生态网络;最后为了充分发挥生态网络功能从而精准建设生态空间,基于已构建的生态网络,结合实际情况,将廊道与节点分为重要和一般两类,确定其空间建设范围,优化生态网络,综合构建生态安全格局,并提出优化策略。研究结论如下:(1)2000-2020年间,咸阳市耕地面积大量减少且减速变慢,草地减少幅度小于耕地但减速加快;建设用地面积大量增加,林地增加略少于建设用地,水域和未利用地增加很少,增速均有所降低。总体看来地类变化平稳但有转变速度加快的趋势,地类转移中最突出的是大量耕地转为建设用地以及草地、耕地、林地间的相互转化,这与城市化加快、产业结构调整以及生态安全保护等因素密切相关。(2)2012-2020年间,咸阳市土地生态安全等级从较不安全提升到比较安全,土地生态安全综合值由0.2120上升到0.7536,其中响应层增加最多,压力层次之,状态层最少。从整体指标看来城镇化和景观破碎是对咸阳市生态安全影响最大的负面因素,需要加强景观斑块之间的联系从而提升生态安全水平。(3)为了使源地同时具备空间连通与功能完整的优势,运用MSPA法和In VEST模型生境质量模块并人工补充后综合识别出20个生态源地,包含了研究区内重要的自然保护区和自然公园。基于MCR模型提取并补充后形成191条生态廊道,识别47个生态节点,构建以源地、廊道和节点为核心的生态网络,研究区中部和北部生态网络分布密集,表明咸阳市中部和北部地区生态连通和完整性较高。(4)将廊道与节点分为重要和一般两类,确定廊道宽度分别为140m和120m,节点建设范围分别为420m和240m,在此基础上综合构建生态安全格局。针对研究区生态源地和廊道分布不均匀现象,提出保护北部并发展南部生态源地,建设廊道缓冲区及发展道路河流廊道,维护管理生态节点的优化策略,以期形成更完整的生态格局,提升区域生态服务功能。更多还原

【Abstract】 Ecological security serves as a crucial cornerstone of the national security system.Timely evaluation of the regional ecological environment and the construction of an ecological security pattern based on the actual situation of the region are the foundation for achieving ecological security.Xianyang City is the central area of the ecological security barrier pattern in the Yellow River Basin,with an important ecological location.This article studies the changes in land ecological security and the construction of ecological security patterns in Xianyang City,aiming to promote the continuous improvement of the ecological environment in Xianyang City,balance regional development and protection.Firstly,starting from the changes in land use in Xianyang City,based on the three periods of land use data in 2000,2010,and 2020,combined with the dynamic degree of land use and transfer matrix,analyze the scale changes and transfer situations of various categories in each region;Secondly,based on the interaction between human activity pressure,land status changes,and management decision responses,a PSR model is used to construct an evaluation index system,analyzing the three major elements of PSR and the overall changes in land ecological security;Then,in order to alleviate the problem of landscape fragmentation and strengthen ecological spatial connections,the MCR model is used to extract and supplement ecological corridors,identify ecological nodes,and construct an ecological network;Finally,in order to fully leverage the functions of the ecological network and accurately construct ecological spaces,based on the already constructed ecological network and combined with the actual situation,the corridors and nodes are divided into two categories: important and general.The spatial construction scope is determined,the ecological network is optimized,a comprehensive ecological security grid is constructed,and optimization strategies are proposed.The research conclusion is as follows:(1)Between 2000 and 2020,the cultivated land area in Xianyang City significantly decreased and slowed down,with a smaller reduction in grassland compared to cultivated land but an accelerated slowdown;The area of construction land has increased significantly,while the increase in forest land is slightly less than that of construction land.The increase in water bodies and unused land is minimal,and the growth rate has decreased.Overall,there is a steady but accelerating trend in land type changes.The most prominent aspect of land type transfer is the conversion of a large amount of arable land to construction land,as well as the mutual transformation between grasslands,arable land,and forest land.This is closely related to factors such as accelerated urbanization,industrial structure adjustment,and ecological security protection.(2)Between 2012 and 2020,the land ecological security level in Xianyang City increased from relatively unsafe to relatively safe,and the comprehensive value of land ecological security increased from 0.2120 to 0.7536.Among them,the response layer increased the most,the pressure layer was the second,and the state layer was the least.From the overall indicators,urbanization and landscape fragmentation are the most negative factors affecting the ecological security of Xianyang City.It is necessary to strengthen the connection between landscape patches to improve the level of ecological security.(3)In order to achieve the advantages of spatial connectivity and complete functionality of the source areas,the MSPA method and In VEST model habitat quality module were used and manually supplemented to comprehensively identify 20 ecological source areas,including important nature reserves and parks in the study area.Based on the MCR model extraction and supplementation,191 ecological corridors were formed,47 ecological nodes were identified,and an ecological network with source areas,corridors,and nodes as the core was constructed.The distribution of ecological networks in the central and northern parts of the study area was dense,indicating high ecological connectivity and integrity in the central and northern parts of Xianyang City.(4)Divide the corridor and nodes into two categories: important and general.Determine the width of the corridor as 140 m and 120 m respectively,and the construction scope of the nodes as 420 m and 240 m respectively.Based on this,comprehensively construct an ecological security pattern.In response to the uneven distribution of ecological source areas and corridors in the research area,optimization strategies are proposed to protect the northern and develop the southern ecological source areas,construct corridor buffer zones and develop road and river corridors,maintain and manage ecological nodes,in order to form a more complete ecological pattern and enhance regional ecological service functions.更多还原