【作者】 倪忠云；

【导师】 孙传敏； 何政伟；

【作者基本信息】 成都理工大学 ， 第四纪地质学， 2011， 博士

【摘要】 生态地质环境承载力是地质环境、生态环境和社会经济环境的综合作用系统的标度,是制定国土资源开发模式的必要依据。研究区地处青藏高原地质构造活跃带,占据西藏“一江两河”开发流域主体,形成以河谷地带为主体的资源利用格局,亟待探究区内丰富资源、脆弱环境以及日益增强的人类活动之间的时间与空间耦合效应,构建“资源-环境-人”之间的协同开发关系。论文选取西藏曲水-桑日地区为研究原型区,系统收集气象、地形、地质、化探、物探和遥感等多源数据,采用遥感、地理信息系统和数理统计等技术与方法,以生态地质环境空间分异和演变时间尺度效应为主线,对生态地质环境承载力系统、子系统和要素进行评价与分析。研究1991-2007年气候变化规律;挖掘地质环境特征信息;提取1988、2000、2009年三期植被覆盖度和土地利用信息及其演变规律,从沙化与湖泊演化揭示环境变化效应;探讨1993-2009年间表层土壤和地表水环境变化机制;构建生态地质环境承载力评价指标体系,实现承载力优、良、中、差分级与区划;制定与承载力匹配的国土资源开发模式。论文研究取得成果如下:(1)多期次地质事件叠加和漫长地质历史演化奠定国土资源多样性与生态地质环境脆弱性基础,人类活动加剧了区域脆弱性分异,导致表层土壤、地表水和矿区地下水等出现异常波动。(2)1991-2007年各项气象指标呈现周期性震荡和自适应调整;气温呈现震荡上升变化;降水整体经过2000年前后的极大值,恢复至20世纪90年代初期水平;相对湿度变化平缓,极值出现滞后于降水极值年份,变化周期较之于降水周期长,整体呈现降低态势;北部和东部平均风速较之南部和西部变化更为频繁且变化率更大;最大风速大多为北风。(3)高植被覆盖度和低植被覆盖度区域面积占据主体,表现为哑铃状结构特征,导致生态环境变化在局部易出现恒强或恒弱等难以调控的特征;1988-2009年间,植被覆盖度向相邻级别缓慢转移;植被覆盖度为70-80%区域面积增加率最大,植被覆盖度为10-20%区域面积减少率最大,与植被覆盖度哑铃状结构的极化演变吻合。(4)土地利用在景观和斑块两个层次发生演变,因人类作用强度增加,地类斑块数目增加,各地类边界均发生不同程度形变。具有环境敏感性指针的低海拔沙化和高海拔湖泊变化与区域气候变化呈高度耦合性,反映环境变化在水平和垂直空间尺度的协同性。雅鲁藏布江北岸以及拉萨河东岸,沙化面积和厚度巨大,1988-2009年间大致维持恶化态势,局部沙地甚至翻越山脊连结成片。1988-2009年间湖泊面积变化率均值为-9.14%,最大值出现在海拔为5100-5200m区域,最小值出现在海拔<5000m区域;湖泊周长变化率均值为-4.47%,最大值出现在5100-5200m区域,最小值为5200-5300m。(5)生态地质环境承载力为良和优的两类区域沿着重点研究区边界成环状分布,承载力差的区域占据高海拔,承载力中的区域位于优、良和差的区域的中间过渡地带,形成承载力区划主体。承载力优的区域分布面积最小,被其他级别区域包围,是人类活动影响强度较大的区域,地质环境稳定,但社会经济环境对生态环境扰动递增,承载力降低的风险最大。承载力良的区域是承载力优的区域的保护外壳,承担承载力优的区域内的人类活动转移,承载力降低的风险较大;承载力中的区域主要为畜牧业和矿业开发的主体区域,地质环境和生态环境稳定性较差,需要控制人类活动不利影响,避免区域承载力总体失衡。承载力差的区域多为高海拔,人类活动强度逐步增加,极易将不利影响扩散至其他区域。更多还原

【Abstract】 Eco-geological environmental carrying capacity composed of geological environment, ecological environment and socio-economic environment is an indicator, and it is also an important basis of land resources development model. The study area is located in the active zone of geological structure in Tibetan Plateau, and is the main region of watershed of the Yarlung Zangbo River, the Lhasa River, and the Nyang Qu. The valleys are the main developing region in the study area, the relationship among the abundant resources, fragile environment and increasing human activities is becoming more complex. It is value to study the coupling effect between time and space, and construct harmonious developing relationship among resource, environment and human.Qushui to Sangri area in Tibet is selected as study area, weather, topography, geology, geochemical, geophysical, remote sensing data are systemicly collected, and the remote sensing technology, geographic information system technology, and mathematical statistics method are used, the effect of eco-geological environmental space differentiation and time succession is selected as the study principal line, then the eco-geological environmental carrying capacity of systems, subsystems and the factors are assessed and analyzed. The main work as follows: studied the climatic change principle; mined the geological environmental characteristic information; interpreted the vegetation covering and land use in 1988, 2000, and 2009, and study the evolution law from 1988 to 2009, especially revealed the environmental evolution law by studying the desertification and lakes; discussed the evolution mechanism of soil and the surface water from 1993 to 2009; constructed the assessment index of eco-geological environmental carrying capacity, and got four levels regions of carrying capacity excellent, good, moderate, and poor; designed land resources development model.Research results are as follows:(1)Many times geological events and evolution of long geological history laid the foundation of the diversity of land resources and vulnerability of ecological geological environment, added with the increasing human activities, the regional vulnerability differentiation becomes more serious, and lead to the abnormal fluctuations of soil, surface water ,and mining groundwater.(2)Some weather index presented periodicity shock and adaptive adjustment from 1991 to 2007; Temperature rose accompany by shocks; the precipitation reached the maximum value about 2000, and then returned to the level of the early 1990s; Relative humidity reduced gently, its extremum appeared later than the precipitation, and its changes cycle longer than the precipitation; the average wind speed in the northern and eastern changed more frequently and greaterly than in the south and west; The maximum wind speed mostly is the north wind.(3)The area of high and low vegetation coverage which showed as the dumbbell structure features occupied the main body, leads to ecological environmental evolution appeared constant strong or weak which is difficult to control. From 1988 to 2009, vegetation coverage shifted slowly to the adjacent levels, the most increasing is vegetation coverage70% to 80%, and the most decreasing is vegetation coverage10% to 20%, the vegetation coverage evolution is coincide with the dumbbell structure features.(4)Land use evolved at landscape and patches levels. Because of the increasing intensity of human activity, the boundary of each land types occurred different degree of deformation. Desertification at relative low altitude and lakes at relative high altitude simultaneously changed which was highly consistent with the regional climate change; all of this shows that environmental change in the horizontal and vertical spatial scales is consistent. In the northern Brahmaputra bank and the eastern Lhasa River bank, the area and thickness of the desertification are great, from 1988 to 2009; the desertification remained deteriorating, in some region, sand even spread through the ridge and linked into one piece. From 1988 to 2009, the change rate of lake area is -9.14%, the maximum value is the region of elevation from 5100m to 5200m, the minimum value is the region of elevation less than 5000m; the average change value of lake perimeter is -4.47%, the maximum value is the region of elevation 5100m to 5200m, while the minimum value is the region of elevation 5200m to 5300m.(5)The excellent and good levels eco-geological environmental carrying capacity distributes a ring form along the border of the key research areas, the poor level region of carrying capacity distributes at relative high altitude, and the medium level region formed the main division is located in the transition zone of the excellent, the good, and the poor regions. The area of excellent level carrying capacity is least, and surrounded by other levels, there is a large number of human activities, although the geological environment is stable, but Socio-economic environment influence on ecological is increasing, thus the excellent level regions face an increased eco-geological risk. The good level region is the protective shell of the excellent level region, there is more and more human activities transferred from the excellent level region, thus there is also face some extent increased eco-geological risk. The medium level region where there is a number of animal husbandry and mining development activities, the geological environment and ecological environment is less stable, human activities need to be controlled, then environmental balance can be maintained. In the poor level region, the intensity of human activities is gradually increasing, and it would spread its adverse effects to other regions, so it is important to protect environment and reduce disturbance.更多还原