金沙江小流域景观格局变化与土壤侵蚀的耦合作用——以云南蒋家沟为例
文献类型：学位论文
| 作者 | 林勇明 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 崔鹏 |
| 关键词 | 蒋家沟流域 景观格局 水土流失 动态模拟 耦合作用 |
| 其他题名 | Study on Interactions of Landscape Change and Soil erosion in the Typical Watershed of Jinsha River |
| 学位专业 | 自然地理学 |
| 中文摘要 | 水土流失作为金沙江流域重大生态环境问题之一，已严重影响了流域生态系统的稳定性和可持续发展。流域的土壤侵蚀和景观演化规律及其合理预测研究，对生态环境建设和退化生态系统恢复有重要意义。本文以水土保持学和景观生态学原理为基础，采用野外调查、核素示踪技术、遥感和地理信息系统技术，对金沙江流域内代表性小流域——蒋家沟流域景观格局变化与土壤侵蚀的耦合作用进行研究，通过研究，获得下列主要成果：1）查明了不同气候区137Cs背景值，并分析了不同土地利用方式土壤剖面137Cs的分布特征。通过分析流域137Cs背景值与降水量的变异性，发现受流域不同气候区降雨量差异影响，不同气候区背景值不同。同时，研究了不同土地利用方式土壤剖面137Cs的分布特征，为137Cs示踪侵蚀量的计算提供基础信息。2）利用137Cs示踪技术，揭示了流域内土壤侵蚀的区域规律。地形因素对坡面侵蚀强度产生不同程度的影响：137Cs的变化不仅受坡长变化影响，还受其坡面坡度和坡形的影响；侵蚀强度随坡度增大而增大，坡面侵蚀与坡度呈较好的相关性。各类用地按照侵蚀模数，依次是裸地>坡耕地>草地>针叶林>阔叶林>水田，裸地是该流域的主要侵蚀源。选用改进质量平衡模型求算坡耕地侵蚀量，得出典型陡坡耕地达到中度侵蚀强度，说明本区坡耕地土壤侵蚀形势严峻。不同土地利用类型组合坡面土壤侵蚀强度均小于单纯坡耕地坡面，属于轻度侵蚀。3）利用GIS和RS技术，探索流域内景观的时空变化，揭示其时空规律。在蒋家沟流域中，草地、裸地是2个主要景观类型，二者面积与周长之和分别占流域总面积与总周长的47.34%和41.84%。其中，草地是该流域的基质，在控制景观整体结构、功能和动态过程中起主导作用。景观要素斑块特征分析结果表明，流域景观要素的面积、周长、斑块数分布均极不平衡，各景观要素斑块形状、分离度与破坏化程度差异大。人类经营活动的干扰和滑坡崩塌、泥石流灾害的叠加效应是导致流域景观破碎的主导因素。在大尺度上，地形因素是形成蒋家沟流域景观分异的首要主导因素。以水热条件为代表的气候条件差异、植被演替变化、灾害频发以及人为影响因子，则成为区内景观分异的第二位影响因素。景观空间格局动态分析表明：1973～2006年间蒋家沟流域的景观多样性与优势度未有显著的变化，但均匀度及破碎度发生显著变化，景观格局总体上发生强烈改变。从局部上看，流域主要变化景观为阔叶林、针叶林、灌木林与坡耕地，人为干扰与灾害活动的加强导致景观破碎化加剧。同时，利用分室模型模拟干扰影响景观格局的研究表明：加大干扰强度在短期内可促使景观多样性增加，随着时间的推移，景观多样性将不断降低。4）将景观格局变化与土壤侵蚀变化进行综合分析，从植被演替与土壤侵蚀的关系到全流域景观变化与侵蚀变化关系，阐明景观变化与土壤侵蚀变化的耦合关系。以137Cs示踪技术为手段，采用“空间代替时间”方法，选择未受人为严重干扰的五个演替阶段（草地群落—灌木林—幼龄林—中龄森林—近成熟森林），研究植被演替与土壤侵蚀的关系。研究结果表明，随着演替进展，群落结构愈加复杂，影响环境能力不断提高，系统功能逐渐完善，群落保持水土的能力逐渐增大，137Cs流失量、土壤平均侵蚀模数、年均土壤侵蚀厚度呈线性下降的趋势。根据土壤侵蚀等级划分结果可得出，蒋家沟流域1973年至2006年期间，中度侵蚀与极强度侵蚀面积变化最大，强度侵蚀与微度侵蚀变化幅度次之，剧烈侵蚀与轻度侵蚀面积变化不大。通过对景观格局变化与土壤侵蚀强度耦合关系的研究，再次说明不同景观类型对土壤侵蚀的发育有着不同影响，不合理的景观格局转变导致土壤性状的变化，最终会引起严重的水土流失，而土壤侵蚀又引起景观格局朝不良方向演变。5）提出了强烈侵蚀流域生态恢复和水土保持对策。分析了流域生态环境退化的现状、主要人为驱动因子，并参照生态功能分区原则，将蒋家沟流域划分为5个生态恢复区和10个生态恢复小区，提出相应的恢复方法。同时，为了支撑恢复方法的运行，提出了配套的管理措施。 |
| 英文摘要 | Soil and water loss which was known as a major ecological and environmental problem has limited severely ecosystem stability and sustainable development of Jingsha River. In the near future, cascaded exploitation in Jingsha River necessitates the reduction of sediment transport and control of soil and water loss. If this problem is not adequately addressed, not only the functionality of reservoir will be undermined due to siltation, but the ecological security of Jingsha River will also suffer. The study of soil erosion and deposition law and its reasonable prediction have an important significance for ecological system construction and reconvention. In this dissertation, based on integration of techniques and methods such as field investigation, 137Cs tracing technique, Geographical Information System, Remote sensing and runoff plot experiment, with the theoretical support of Landscape Ecology and Soil Erosion, interaction between landscape change and soil erosion in typical watershed were analyzed and discussed in detail. The main results are as follows:1）Due to the variation coefficients of 137Cs background value and the amounts of precipitation among different sampling sites in the watershed, 137Cs background values were different. Meanwhile, the characters of 137Cs distributions in soil profiles in different land using patterns were studied to provide a foundation for using 137Cs tracer to estimate soil erosion.2）In topographical indices, 137Cs loss was controlled not only by slope length, but also by slope gradient and slope shape. The relativity between erosion modulus and slope gradients is superior to that between erosion modulus and slope length, which indicates that hill slope with higher gradient, suffers more serious soil erosion. Under different land use pattern, the order of soil erosion intensity is as follows: bare rock>sloping field>grassland>coniferous forest >broad-leaved forest>paddy.Based on improved mass balance model I, according to the soil erosion degree standard promulgated by national water conservancy bureau in 1997, average soil erosion rate of typical cultivated sloping field belongs to moderate erosion. Relatively, average soil erosion rate of spatial matching of different land uses belongs to light erosion.3）According to the classification principles of landscape ecology, twelve landscape elements of Jiangjia Gully were set up. The landscape elements included sloping field, paddy, terrace, residential land, broad-leaved forest, coniferous forest, grassland, shrub, bare rock, gully, debris flow fan, and road. Among them, grassland and bare rock were main components, whose area and perimeter accounted for 47.34% of the total area and 41.84% of the total perimeter, respectively, and grassland was dominant in controlling landscape structure, function and dynamic processes.The results of patch characteristics showed that area, perimeter and the number of patches for different landscape elements were uneven, and the distribution trend of perimeter was similar to that of area, while the relationships between the number of patches and area, perimeter could not be found. From the indices of patch shape, fragmentation, and separation, it could be concluded that grassland and gully were tow most complicated landscapes in patch shape and least in fragmentation and separation, while residential land was on the contrary, which was the simplest in patch shape and highest in fragmentation and separation. This proved that cumulative effect between hazards (including landslide, collapse, and debris flow) and human activity was the main factors breaking the landscape into fragments and separation.Using layer overlay analysis of the landscape pattern maps and digital elevation model (DEM), the distribution variation pattern of different landscape elements was studied. The results showed that topographic characteristics are critical, and climate differentiation, vegetation succession, frequent disasters, and human activity are secondary for the spatial variations of landscapes. Landscape indices including diversity index, dominance index, evenness index, and fragmentation index were used to analyze the changes of spatial pattern for twelve landscape elements of the study area from 1973 to 2006. The results showed that the number of patches of the study area increased from 1151 in 1973 to 1521 in 2006. In other word, the degree of landscape fragmentation had increased over time. In 33 year period, the landscape diversity had decreased from 0.8772 in 1973 to 0.8771 in 2006, while the evenness index and fragmentation index had increased by 0.0463 and by 0.00167 respectively. The overall landscape spatial pattern had been significantly altered from 1973 to 2006. Meanwhile, based upon the transformation matrix, the compartment theory was used to simulate landscape dynamics of different disturbance scenarios in the next five decades under the premise of no changing in the number of landscape types. The results suggested that landscape diversity index and evenness index increased in short term and then decreased due to landscape pattern dominated by one or several landscape elements under disturbance. 4）By using 137Cs tracing technique and adopting space as a substitute for time, five succession stages including grassland, shrub, juvenile forest, middle age forest, and near-maturation forest were chosen to study the relationship between vegetation succession and soil erosion. The results showed that 137Cs loss, average erosion modulus, and average annual depth of soil erosion decreased with the development of succession due to more complicated community structure, better system function, and stronger soil and water conservation.According to the distribution of soil erosion in 1973 and 2006, the moderate and heavy eroded area increased by 4 km2 and 0.04 km2 respectively, intensive and lightly eroded area decreased by 4.63km2 and 1.18km2 respectively. Meanwhile, the interaction between landscape change and soil erosion was analyzed. The result showed that serious soil erosion may happen due to unreasonable change of different landscape elements, and landscape change would develop towards bad direction. 5）Based on the principles of ecological functional regionalization, Jiangjia gully was divided to five ecological restoration regions and ten ecological restoration districts which comparative restoration measures were presented for. Therefore, the management measures for ecological protect and water and soil conservation were presented as follows: population growth must be controlled and population quality should be improved, energy substitute must be explored for alleviating disafforestation, publication and management of ecological protect and soil and water conservation should be strengthened, and fund system should be founded for innovate investment mechanism of ecological protect and soil and water conservation. |
| 学科主题 | 生态学 ; 水土保持学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-15 |
| 分类号 | F32;F30 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2211]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 林勇明. 金沙江小流域景观格局变化与土壤侵蚀的耦合作用——以云南蒋家沟为例[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2008. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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