黄土丘陵区景观格局动态研究

发布时间：2018-04-08 20:12

本文选题：黄土丘陵区　切入点：景观格局动态　出处：《宁夏大学》2015年硕士论文

【摘要】：植被覆盖率低、水土流失严重、沟壑密度大等是黄土丘陵沟壑区的主要特点。宁夏彭阳县属于典型的黄土丘陵沟壑区,不合理的土地利用方式使土地生态系统面临巨大压力。小流域是黄土丘陵沟壑区社会经济和水土流失综合治理的基本研究单元,研究该区县域和小流域尺度上的土地利用/覆被格局变化具有重要的理论及现实意义。本研究广泛总结前人研究成果与经验,结合“景观生态学”的理论与方法,通过野外实地调查,利用遥感、全球卫星定位系统和地理信息系统技术手段,以黄土丘陵区典型县域和小流域作为研究区,在大尺度上较为全面的探讨彭阳县近20年土地利用景观格局与动态,并对相应时段土地利用格局变化的主要驱动力做了详细分析；小尺度上以黄土丘陵区的典型小流域为代表,按流域生态恢复措施划分景观类型,揭示各景观类型的空间分布与海拔、坡度、坡向等地形因子的相互关系,为合理利用自然资源和流域生态恢复提供依据。论文研究结果表明：(1)20年间,彭阳县未利用土地转化率最高,主要向草地和耕地转化。耕地景观是彭阳县1995-2000年的优势景观,草地是该区域2005-2014年的优势景观。2000～2005年间彭阳县土地利用整体变化的幅度最大,速度最快,此阶段也是退耕还林草工程快速推进阶段,人类活动对自然环境的影响较大,草地景观在该阶段增加速度最快,2010～2014年间城镇建设用地增加速度最快的地类,体现该区域受生态移民等政策的影响。彭阳县景观破碎化程度逐年减少,2005-2014年草地景观成为了该区域的优势景观。从研究区的土地利用变化类型,速度以及景观格局变化数据都显示了相应时段国家退耕还林草政策,生态移民政策以及政策调整是彭阳县土地格局变化的主要驱动力。(2)高建堡流域生态恢复景观空间分布与地形因子显著相关,垂直分布特征明显。海拔由低到高,景观类型的分布表现为沟底防冲林→经果林→退耕还林(草)→荒山自然封育→水平梯田→鱼鳞坑整地→荒山造林的顺序；坡度对流域的各景观组分空间分布影响很大,分布比例均呈先逐渐增大后逐渐减小趋势；坡向由阴坡转向阳坡的过程中,退耕还林(草)、水平梯田、荒山造林景观的分布比例减小,荒山自然封育和经果林的分布比例增加,鱼鳞坑及沟底防冲林景观基本不受坡向影响。
[Abstract]:Low vegetation coverage, serious soil erosion and high gully density are the main characteristics of loess hilly and gully region.Pengyang County in Ningxia is a typical loess hilly and gully region. The land ecosystem is under great pressure because of unreasonable land use.Small watershed is the basic research unit of social economy and comprehensive management of soil and water loss in loess hilly and gully region. It is of great theoretical and practical significance to study the change of land use / cover pattern on the scale of county and small watershed in this area.Based on the theory and method of landscape ecology and field investigation, this study summarizes the achievements and experiences of predecessors, and uses remote sensing, global positioning system and geographic information system (GIS) technology, which is based on remote sensing, global positioning system (GPS) and geographic information system (GIS).Taking the typical counties and small watersheds in the loess hilly region as the study area, the landscape pattern and dynamics of land use in Pengyang County in recent 20 years were comprehensively discussed on a large scale, and the main driving forces of the change of land use pattern in the corresponding period were analyzed in detail.On the small scale, the typical small watershed in loess hilly area is taken as the representative, the landscape type is divided according to the ecological restoration measures of the watershed, and the relationship between the spatial distribution of each landscape type and the topographic factors such as elevation, slope, slope direction and so on is revealed.It provides the basis for rational utilization of natural resources and ecological restoration of watershed.The results show that the conversion rate of unused land in Pengyang County is the highest in the past 20 years, and it is mainly converted to grassland and cultivated land.The cultivated land landscape is the dominant landscape in Pengyang County from 1995 to 2000, and the grassland landscape is the dominant landscape in Pengyang County from 2005 to 2014. The overall change of land use in Pengyang County was the largest and the fastest between 2005 and 2005. This stage is also the rapid progress stage of the project of returning farmland to forest and grassland.The impact of human activities on the natural environment is great. The grassland landscape has the fastest increasing rate in this stage and the fastest increase of urban construction land in 2010 and 2014, which shows that the region is affected by ecological migration and other policies.The degree of landscape fragmentation in Pengyang County decreased year by year and grassland landscape became the dominant landscape in Pengyang County from 2005 to 2014.According to the data of land use change type, speed and landscape pattern change in the study area, the national policy of returning cropland to forest and grassland has been shown in the corresponding period.Ecological migration policy and policy adjustment are the main driving force of land pattern change in Pengyang County.From low altitude to high altitude, the distribution of landscape type is shown as the sequence of afforestation of forest with flushing forest at gully bottom and returning farmland to forest (grass) through fruit forest and barren mountain.The gradient has a great influence on the spatial distribution of the landscape components in the watershed, and the distribution ratio is gradually increasing first and then decreasing gradually, and during the process of the slope changing from the shady slope to the sunny slope, the cultivated land is returned to forest (grass and grass, horizontal terrace).The distribution ratio of afforestation landscape of barren mountain decreased, the distribution proportion of natural closure of barren mountain and the distribution proportion of forest through fruit forest increased, and the landscape of fish scale pit and flushing forest at the bottom of gully was not affected by slope direction.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P901

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