塔里木河中游胡杨林景观格局与土壤水文特征研究

发布时间：2018-03-18 06:09

本文选题：塔里木河中游　切入点：胡杨林　出处：《塔里木大学》2015年硕士论文　论文类型：学位论文

【摘要】：塔里木河中游胡杨林区是重要的国家级胡杨林保护区之一，本研究从景观尺度，应用遥感分析技术与地面实地调查相结合的方法，深入探讨了区域景观格局的时空变化特征，同时切入影响区域胡杨林景观格局变化的土壤水文特征这一重要方面，探讨了水文特征的空间分布规律及与典型景观斑块的相互关系，通过研究得到了以下几个方面的结论：（1）1993到2014年间，各类土地利用斑块发生了显著变化，其中农田斑块从无到有，增长较快，而胡杨林斑块则明显下降。期间灌木林持续增长，这反映出整个区域以胡杨为主的森林群落，正在向以灌木林群落为主的荒漠灌木群落方向退化。同时胡杨林景观斑块显示出破碎化过程和景观斑块逐渐消失的特征。（2）1992年至2009年间，土地荒漠化景观变化明显，其中1992年轻度荒漠化面积占主体地位，但是至2009年极重度荒漠化面积已经上升到了第一位，反映了荒漠化趋势比较严重。（3）1992年到2009年间胡杨林区受水文影响的区域范围在逐步缩小。1992年是水文影响范围最为广泛的时期，且在景观空间上的分布更加均匀，但是至2009年大部分区属于重度缺水范围，一些轻度缺水范围逐渐缩小，并向河流沿岸附近集中，且较大面积的水体实际上已经消失殆尽。（4）胡杨林区河流的水文网从1992年至2009年发生了显著变化，1992水文网的空间分布较密集，且空间上能够延伸至大部分区域，至2009年河网逐渐变短，部分区域的河网逐渐消失，河网的空间距离增大。显示出能受到水文网影响的区域在逐渐减少。（5）研究显示不同区域景观斑块中土壤水文物理性质差异比较明显，河岸区土壤1米深土层，平均含水率随着距离河岸越远降低越多，呈明显的下降趋势。反映出河流对景观斑块水量的影响随着离河岸距离的增加而降低。这引起了地表植被的分异，，深根系的乔木更多的分布于靠近河岸的区域，而耐旱的灌木和草本植物则更趋向于分布在过渡区和荒漠区的景观斑块中。土壤水文物理性质中土壤含水率与乔木、灌木和草本的盖度以及乔木和灌木频度呈显著的正相关关系。这符合胡杨林景观斑块多分布在河流水文网周边区域的特征。
[Abstract]:The Populus euphratica forest area in the middle reaches of the Tarim River is one of the important national Populus euphratica forest reserves. In this study, the spatial and temporal characteristics of the regional landscape pattern were discussed from the landscape scale, using the method of remote sensing analysis combined with the field survey on the ground. At the same time, the soil hydrological characteristics of the landscape pattern change of Populus euphratica forest were analyzed. The spatial distribution of the hydrological characteristics and their relationship with the typical landscape patches were discussed, and the following conclusions were obtained from the study. Between 1993 and 2014, there were significant changes in land use patches, in which farmland patches increased rapidly from scratch, while patches of Populus euphratica decreased significantly. Shrubbery continued to increase during the period. This shows that the forest community of Populus euphratica in the whole region is degenerating to desert shrub community which is dominated by shrubbery. Meanwhile, the landscape patches of Populus euphratica forest show the characteristics of fragmentation and gradual disappearance of landscape patches. (2) from 1992 to 2009, the landscape change of land desertification was obvious, of which slight desertification area occupied the main position in 1992, but the extremely serious desertification area had risen to the first place by 2009, which reflected the serious trend of desertification. (3) from 1992 to 2009, the area affected by hydrology in Populus euphratica forest was gradually reduced. 1992 was the most extensive period of hydrological impact, and the distribution of landscape space was more uniform. However, by 2009, most areas of Populus euphratica forest were in the range of severe water shortage. Some of the mild water shortage areas are gradually reduced and concentrated near the river banks, and large areas of water bodies have actually disappeared. (4) the hydrological network of rivers in Populus euphratica forest area changed significantly from 1992 to 2009. The spatial distribution of the hydrological network in 1992 was denser, and the hydrological network could be extended to most of the areas in space. By 2009, the river network became shorter and the river network in some areas gradually disappeared. The spatial distance of the river network increases, indicating that the area affected by the hydrological network is gradually decreasing. The results show that there are obvious differences in the hydrophysical properties of soils in different landscape patches, and the average moisture content decreases with the distance from the riverbank, and the average moisture content decreases with the distance from the riverbank to 1 meter deep soil layer. It shows that the influence of river on the water amount of landscape patches decreases with the increase of the distance from the riverbank, which leads to the differentiation of the surface vegetation, and the trees with deep roots are more distributed in the area near the river bank. The drought-tolerant shrubs and herbaceous plants tend to be distributed in the landscape patches in the transitional areas and desert areas. The coverage of shrubs and herbs as well as the frequency of trees and shrubs were positively correlated, which was consistent with the characteristics of landscape patches of Populus euphratica forest distributed in the surrounding area of river hydrological network.
【学位授予单位】：塔里木大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S792.11;S715

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