Knowledge Resource Center for Ecological Environment in Arid Area
| 江河源区沙漠化脆弱性评价 | |
| 其他题名 | Assessment of Vulnerability to Aeolian Desertification in the Source Areas of the Yangtze and Yellow Rivers |
| 任小玢 | |
| 出版年 | 2017 |
| 学位类型 | 博士 |
| 导师 | 董治宝 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 全球气候变化背景下，随着环境可持续发展问题逐渐受到科学界的广泛重视，预测生态系统的结构和功能以及生态脆弱性对全球变化的响应，成为可持续发展研究的热点问题。将可持续发展领域的脆弱性理论融入沙漠化科学的研究为认识和理解沙漠化问题提供了新的视角。然而，目前国内外沙漠化研究成果中关于沙漠化脆弱性的整体理论和方法研究仍显薄弱。与此同时，江河源区沙漠化问题造成的水土流失严重，土地退化等后果直接威胁到江河源区的水源涵养功能。使用有效地监测手段识别江河源区沙漠化脆弱性较高的地区，提高对沙漠化脆弱性演变过程及成因的认识，是因地制宜地制定江河源区沙漠化防治措施的重要基础。本研究通过梳理脆弱性研究进展，明晰国内外不同研究领域对脆弱性的认识和理解，揭示将脆弱性理论与沙漠化科学研究结合的创新性和重要作用，提出“沙漠化脆弱性”的研究命题及其研究框架。基于IPCC对气候脆弱性的解释及我国沙漠化实际情况，本文明确定义了沙漠化脆弱性的概念及其特征。同时，以江河源区为研究对象，构建了适用于江河源区高寒气候环境的沙漠化脆弱性评价体系；以GIS和RS为主要技术手段，建立江河源区沙漠化脆弱性指标数据库，并计算沙漠化脆弱性指数；基于对沙漠化脆弱性空间格局和时空演变过程的分析，探讨了江河源区沙漠化脆弱性演变的驱动因素。通过沙漠化脆弱性理论基础与实际应用相结合，以期为脆弱性理论在沙漠化科学领域的应用，实现跨学科研究提供方法借鉴，也为江河源区沙漠化防治和恢复提供理论依据。本研究的主要内容如下：（1）明确沙漠化脆弱性理论基础，提出沙漠化脆弱性概念，丰富了沙漠化研究理论体系。本研究将沙漠化脆弱性定义为沙漠化系统要素易受气候变化和人类活动等负面影响的响应程度，是气候的变率特征、幅度和变化速率及其暴露、敏感性和适应性的函数。沙漠化脆弱性由沙漠化系统的内在特征决定，深受气候胁迫压力、自然生态以及社会经济等因素的影响，其与气候变化具有非线性关系；沙漠化脆弱性是相对而言的，绝对稳定或绝对脆弱的情形都不存在，并始终处于动态变化的过程中。（2）构建江河源区沙漠化脆弱性指征体系，整体上发展了沙漠化指征研究。江河源区高寒的气候环境决定了其沙漠化的特殊性，急需在已有沙漠化指征体系的基础上，提出适用于江河源区气候环境的沙漠化脆弱性指征体系。本研究使用多准则分析法，从暴露、敏感性和适应性3个方面选取包括自然因素和社会经济因素在内的8个关键指标，构建了适用于江河源区的沙漠化脆弱性指征体系。选取的指标有地形起伏度、风蚀气候因子指数、年均气温、植被指数、沙漠化土地、极重度沙漠化土地、人口密度和GDP密度（3）通过分析江河源区沙漠化脆弱性空间格局发现，江河源区整体沙漠化脆弱性处于较低水平，局部地区沙漠化脆弱性较高。2000年、2005年和2010年，江河源区极轻度和轻度沙漠化脆弱性分别占江河源区总面积的70%、72%和76%。尽管如此，仍有部分地区具有重度或极重度沙漠化脆弱性，主要分布于长江源区西北部，黄河源区西部和东北部，尤其是黄河源区沙漠化脆弱性较高的地区也是人类经济活动较多的区域，不合理的人类活动会进一步加剧这些地区的沙漠化脆弱性，因此决策者需优先考虑其沙漠化防治、环境保护和生态恢复问题。（4）通过分析江河源区沙漠化脆弱性时空演变趋势发现，2000~2010年江河源区沙漠化脆弱性整体呈降低趋势，且以中等脆弱转变为轻度脆弱和轻度脆弱转变为极轻度脆弱2种过程为主。由于沙漠化脆弱性降低程度微弱，源区整体沙漠化脆弱性维持在比较稳定的状态。研究区沙漠化脆弱性变化具有明显的空间差异性，尤其是河流、湖泊及周边平地等局部地区仍然出现沙漠化脆弱性的升高，与各区域沙漠化脆弱性综合指数的变化趋势相比，这些特殊的变化过程是不可见的。此外，2000~2005年长江源区整体沙漠化脆弱性升高，源区西部沙漠化脆弱性指数明显增大；黄河源区整体沙漠化脆弱性降低，仅若尔盖盆地沙漠化脆弱性微弱上升。2005~2010年，长江源区整体沙漠化脆弱性降低，源区东部沙漠化脆弱性指数增加明显；黄河源区整体沙漠化脆弱性有所上升，玛多境内部分地区以及共和、贵南县境内局部地区沙漠化脆弱性升高明显，若尔盖盆地沙漠化脆弱性降低。（5）江河源区沙漠化脆弱性演变的驱动因素具有区域差异。长江源区气候因素（主要是气温升高）是影响其沙漠化脆弱性发展的主导因素，人类活动对沙漠化脆弱性发展的贡献很少；黄河源区沙漠化脆弱性的演变是在自然因素（如气候变化）的基础上叠加人类活动，两者共同作用的结果；若尔盖盆地不合理人为活动的干扰（主要为过度放牧、湿地排水和泥炭开采）是其沙漠化脆弱性演变的占主导因素。由于江河源区广泛分布永久性或季节性冻土，气温升高而导致的冻土退化是导致研究区沙漠化脆弱性升高的一个潜在特殊原因；由于冻土退化过程预防难度较大，同时不合理人为活动的干扰会加剧冻土退化引起的沙漠化，因此需要特别重视人类活动对江河源区的沙漠化脆弱性的影响。值得注意的是，近十几年来一系列环境治理措施的实施，尤其是2005年以来江河源区生态修复工程的实施已经取得了显著成效，源区牲畜数量明显减少，整体沙漠化脆弱性明显降低。本研究的创新点和主要贡献为：（1）在理论体系上，本研究系统回顾脆弱性研究的现状和挑战，开展了沙漠化脆弱性研究。基于对脆弱性概念发展的简要回顾，结合气候变化研究中的脆弱性定义提出沙漠化脆弱性的概念和理论研究框架，明确沙漠化脆弱性的内在特征，并依据沙漠化系统的特点阐释了沙漠化脆弱性评价体系、评价内容和评价方法，丰富了沙漠化科学和脆弱性理论体系和研究视角。（2）在研究方法上，基于沙漠化脆弱性理论和江河源区高寒环境下沙漠化的特殊性，本研究使用多准则分析法，选择包含自然因素和人为因素在内的8个关键指标构建沙漠化脆弱性指针体系；以RS与GIS为主要手段，建立研究区沙漠化脆弱性指标数据库并计算沙漠化脆弱性指数（DVI）。（3）在实践应用上，从时间和空间两个层面，分析了江河源区沙漠化脆弱性的空间格局和演变过程，并从自然条件和人类活动两方面探讨了沙漠化脆弱性演变的驱动因素。 |
| 英文摘要 | On the context of climate change, the environmental problem of sustainable development has gradually attracted extensive attention by the scientific community. In the study on sustainable development, it has become a hot issue that predicting the structure and function of ecosystem and ecological vulnerability response to the global change. Aeolian desertification is a major type of desertification characterized by the action of blowing sand, and results from a combination of climate change with intensive or unsustainable human activities in areas with a fragile ecological environment. In the past 50 years, desertification research has greatly enriched China Desert Science due to its theory progresses on innovation and systematicness, and practical achievements on economic, social and environmental effects. However, the vulnerability theory applied in the aeolian desertification science is limited, especially there are very few works on the theoretical framework and basic research methods of vulnerability to aeolian desertification. Moreover, in recent decades, the rapid development of aeolian desertification, accompanied by the expansion of soil erosion, land degradation, damage to the soil structure, and loss of soil nutrients, has also had negative consequences for the regional water conservation and supply functions. To combat this aeolian desertification, it is necessary to improve our knowledge of its causes and consequences and to identify efficient monitoring tools.In this study, we completed a systematic review of the development of vulnerability, and distinguished the different understanding among different fields of study, which revealed the innovative and important role of vulnerability in the field of desertification science. We proposed the research topic of vulnerability to aeolain desertification and its framework, which could provide a new perspective to improve our knowledge of aeolian desertification. Based on the explanation of vulnerability to climate change proposed by IPCC and definition of aeolain desertification in China, we clearly defined the concept and characteristics of vulnerability to aeolian desertification. Then, we assessed the vulnerability to aeolian desertification in the source areas of the Yangtze and Yellow Rivers by developing an evaluation model supported by GIS and RS technologies. Considering the cold climate of the source areas, we developed an indicator system to assess the vulnerability of land in the source areas of the two rivers to aeolian desertification. At the same time, we used the AHP method to develop appropriate factor weights to support our model of desertification vulnerability index (DVI) and identify the areas of highest vulnerability to aeolian desertification in the source areas of the Yangtze and Yellow Rivers. Moreover, we analyze the spatial distribution of vulnerability to aeolian desertification and its changes between 2000 and 2010 to estimate the trends and identify the driving forces responsible for these trends.Major results of this paper were outlined as follow:(1) We clearly proposed the theoretic foundation and defined the concept of vulnerability to aeolian desertification, which enriched the theoretic system of desertification research. We defined vulnerability to aeolian desertification as the response degree to which desertification system are susceptible to, unable to cope with, adverse impacts of climate change and anthropogenic activities, which is the function that depends on the variability characteristics, amplitude and rate of climate, and exposure, sensitivity and adaptability. Vulnerability to aeolian desertification is determined by the inherent characteristics of desertification system, resulting from the stress of climate, natural ecology and social economic. The relationship between vulnerability to aeolian desertification and climate change is not entirely simple linear or nonlinear. Relatively speaking, there is no absolute stable or unstable vulnerability, which is constrained by various factors and always in a dynamic process.(2) We developed an indicator system to assess vulnerability to aeolian desertification, which extended the research of aeolian desertification indicators. Due to the cold environment of study area, it is necessary to propose a new indicator system applicable in the source areas of the Yangtze and Yellow Rivers on the basis of existing indicator system of desertification. We adopted multi criteria analysis and selected eight indicators, including two aspects of natural factors and anthropogenic activities, to develop the indicator system of vulnerability to aeolian desertification.(3) In the source areas of the Yangtze and Yellow Rivers, land with very low or low vulnerability to aeolian desertification was widely distributed, accounting for 69%, 70% and 82% of total area in 2000, 2005 and 2010, respectively. Moreover, we found that in this fragile, vulnerable environment, a large part of the area highly vulnerable to aeolian desertification. Land with the highest vulnerability is concentrated in the northwestern part of the source areas of the Yangtze River and the northwestern and northeastern parts of the source areas of the Yellow River. Especially, land with high vulnerability is the region accompanying with more human activities, which could be further aggravating the vulnerability to aeolian desertification in the source areas of the Yellow River, so decision-makers must prioritize these areas for protection and ecological restoration.(4) Although the overall trend from 2000 to 2010 showed an decrease in vulnerability, the decrease was relatively small, suggesting that vulnerability remained largely stable for the overall study area. Meanwhile, the trends in specific areas (e.g., river valleys and the flat areas around lake) reveal important vulnerabilities that are not visible based only on the overall values for each sub-region. Moreover, from 2000 to 2005,the vulnerability to aeolian desertification increased slightly in the source area of the Yangtze River, with the obvious increasing of DVI in the east of the region. The vulnerability to aeolian desertification decreased in the source area of the Yellow River, showing a slight increasing of DVI in the Zoige Basin. From 2005 to 2010, the overall trend of vulnerability decreased feebly in the source area of the Yangtze River, with the increasing of DVI in the west of the region. In addition, the vulnerability increased slightly in the source area of the Yellow River. Especially near the Maduo, Gonghe and Guinan counties, vulnerability to aeolian desertification increased obviously, which may result from unreasonable anthropogenic activities.(5) The driving forces responsible for the observed changes in vulnerability differed among the sub-regions. In the source areas of the Yangtze River, climatic factors (primarily a trend of rising temperatures) were the dominant factor. In the Zoige Basin, human activities (primarily overgrazing and drainage of marshes) were the dominant factors. In addition, a combination of climatic and human factors caused the trend of vulnerability to aeolain desertification in the source areas of the Yellow River. Because of the large areas of permanently or seasonally frozen ground in the study area, rising temperatures that increase thawing are a particular concern, both because they cannot be prevented and because their effects will be exacerbated by the effects of human activities. Thus, human activities must be managed particularly carefully in these areas. In the recent decade, the implementation of the ecological restoration projects in the source areas of the Yangtze and Yellow Rivers, especially since 2005, has a achieved a noticeable effect, which is reflected by the decreasing number of livestock and vulnerability over the whole study area.The contributions of this study are:(1) From the perspective of theoretical framework, we put forward the research topic of “vulnerability to aeolian desertification” after comprehensively reviewing the development of vulnerability. In conjunction with the research of vulnerability to climate, we proposed the concept of vulnerability to aeolian desertification and its theoretical framework. Meanwhile, we illustrated the evaluation system, evaluation content and evaluation method for the vulnerability to aeolian desertification based on the characteristic of aeolian desertification system, which could provide a new perspective to improve our knowledge of the aeolain desertification science and vulnerability theoretical framework. (2) From the perspective of research methodology, considering the cold and fragile environment of the study area, we developed an indicator system to assess the vulnerability to aeolian desertification in the source areas of the Yangtze and Yellow Rivers. Eight indicators were selected including natural and anthropogenic factors by principle d of multi criteria analysis. At same time, model of desertification vulnerability index (DVI) was used to assess the vulnerability of source areas. (3) From the perspective of practical application, considering the two dimensions of spatial and temporal, we analyzed the distribution of vulnerability to aeolian desertification and its changes between 2000 and 2010 in the source areas of the Yangtze and Yellow Rivers, to estimate the trends and identify the driving forces responsible for these trends. |
| 中文关键词 | 脆弱性 ; 沙漠化 ; RS ; GIS ; 江河源区 |
| 英文关键词 | vulnerability aeolian desertification remote sensing GIS headwaters of the Yangtze and Yellow Rivers |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287843 |
| 推荐引用方式 GB/T 7714 | 任小玢. 江河源区沙漠化脆弱性评价[D]. 中国科学院大学,2017. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [任小玢]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [任小玢]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [任小玢]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
