【作者】 赵静；

【导师】 周志翔；

【作者基本信息】 华中农业大学 ， 生态学， 2008， 硕士

【摘要】 土地利用/土地覆被变化(LUCC)在全球环境变化与可持续发展研究中占有重要地位。遥感技术因其具有宏观、动态、快速、研究面积广等优点,已成为监测土地利用/覆被变化的主要手段。植被覆盖是土地覆盖最主要的部分,现已成为广大专家学者研究的热点和重点内容。本文以三峡库区为研究对象,基于1988年、2000年和2007年三期遥感影像,采用非监督分类的方法提取近20年来该地区的植被覆盖变化信息。通过面积转移矩阵、土地利用动态度及动态趋势变化指标和土地利用程度指标分析了三峡库区这20年来植被覆盖的时空变化,并分析了影响植被覆盖变化的主要驱动力因子,得出如下结论:(1)运用非监督分类方法提取三峡库区1988年、2000年和2007年三期的植被覆盖信息。分类结果表明,总体精度保持在85%左右,可以满足一般分类图像精度要求。(2)三峡库区20年来植被覆盖总面积呈下降趋势,下降趋势在逐渐减缓。库区内乔木林(针叶林、阔叶林、针阔混交林)面积减少且变化量较大,而灌木林面积呈增加趋势,反映了库区内森林保护和植被恢复的任务依然艰巨。(3)通过面积转移矩阵获取了各种植被覆盖类型内部及其与其他土地利用类型间的相互转化关系。结果表明,1988-2000年的转化趋势主要是各植被覆盖类型内部及其与耕地间的转化。针叶林主要向耕地和灌丛转移;阔叶林的主要转出类型为针叶林;针阔混交林主要转出类型是耕地;灌丛主要向耕地转换。2000-2007年的转换趋势主要是各植被覆盖类型与耕地间的转换,针叶林、阔叶林、针阔混交林及灌丛对耕地的转移率分别为8.27%、60.33%、47.24%和29.11%,贡献率分别为3.92%、10.15%、1.04%和13.18%。同时研究发现,这个时期各植被类型向城镇村及工矿用地的转移率及贡献率均明显高于上一研究期。(4)引入单一土地利用动态度、动态变化趋势状态指数及综合土地利用动态度、综合变化趋势状态指数等指标对植被覆盖变化的速度和趋势进行分析,研究结果表明,三峡库区内单一植被覆盖类型在2000～2007年间转换较频繁,变化速度较快。由于各植被类型间的相互消长,整体植被覆盖变化仍处于平衡状态。(5)计算了三峡库区1988年、2000年和2007年土地利用程度指数,发现三峡库区整体土地利用程度处于中等以上水平,高于全国平均水平,研究得出三峡库区土地利用的强度呈明显增大的趋势。同时定性描述了影响三峡库区植被覆盖变化的四个驱动力因子,分别为三峡工程建设、国家政策、经济发展与城市化建设和人口压力。更多还原

【Abstract】 Land use/land cover change (LUCC) play an important role in the study of global environment change and sustainable development. Remote sensing (RS) has become the main technology in monitoring land use/cover change, due to its quick, dynamic and various advantages. The vegetation cover is the most main part of the land covers, and now it has become the hot that the general experts study. In Basing on remote sensing images, we extracted the information of vegetation cover change and analysed the dynamic change in the Three Gorges Reservoir Area from 1988 to 2007. In this paper, the Unsupervised Classfication was used to classify the vegetation cover types, and some mathematic models were applied to study the spatio-temporal changes of vegetation cover during the 20 years in the Three Gorges Reservoir Area, such as vegetation cover type transferring matrix model, land use dynamic model and land use degree model. At last, the driving forces were analyzed based on the vegetation cover change. The main results showed:1. By using the Unsupervised Classfication method to extract the information of vegetation cover change in the Three Gorges Reservoir Area from 1988 to 2007, the result showed that the overall accuracy is only about 85%. It is not fit for strict study.2. The area of the vegetation cover decreased continuously during the past 20 years in the Three Gorges Reservoir Area, but the rate had a slower decrease. The area of the arbor forset (including conifer forest, broadleaved forest and conifer broadleaved forest) had reduced and the change quantity was very large, however, the area of the shrubbery had increased constantly. It was indicated that the vegetation in the Three Gorges Reservoir Area had been destroyed, especially the arbor forest, and the ecological environment declined. So the duty to the forest protection and the vegetation restore was still arduous.3. With the help of area transfer matrix of vegetation cover change, the interactive transfer relation of four types vegetation cover was also analyzed. The results showed that the main transfer direction during the period of 1988-2000 was the mutual transfer in various vegetations cover type and between the vegetation cover types and the farming land. Conifer forest transferred mainly into farming land and shrubbery, broadleaved forest into conifer forest mainly, conifer broadleaved forest into farming land mainly, and shrubbery into farming land mainly. The main tendency during 2000-2007 was the mutual transfer only between the vegetation cover types and the farming land. The rate of the transfer of conifer forest、broadleaved forest、conifer broadleaved forest and shrubbery into farming land were 8.27%, 60.33%, 47.2% and 29.11% respectively; and the rate of contribution were 3.92%, 10.15%, 1.04% and 13.18% respectively. And it was also found that the transfer rate and contribution rate of the vegetation cover type turning into the residential land in 2000-2007 had been higher than in 1988-2000.4. By using the land cover indexes of land use dynamic、trend and state of land use change to analyse the rate and trend of the vegetation cover change, the results showed that the single vegetation cover type transformed frequently and the variation rate was quick during 2000-2007 years in the Three Gorges Reservoir Area. In totally, the vegetation cover change had remained the balance state because of the mutual transfer between the different vegetation cover types.5. Through calculating the land use degree index in 1988, 2000 and 2007 of the Three Gorges Reservoir Area, it was discovered that the total land use degree index of Three Gorges Reservoir Area was above the medium level and higher than the national average level. At the same time, the study showed that the tendency of the land use degree in the Three Gorges Reservoir Area increased obviously. Then four forces driving the vegetation cover change in the Three Gorges Reservoir Area had been qualitatively described. They were the Three Gorges Project, national policy, economic development and urbanized construction and population perssure respectively.更多还原