巴音布鲁克草原湿地景观格局变化及其水文驱动机制研究

发布时间：2018-07-17 05:41

【摘要】：巴音布鲁克草原湿地发育在天山南坡的尤勒都斯山间构造盆地之中,湿地的形成主要缘于大范围干旱区中天山褶皱断块隆起导致的高海拔冷湿气候。作为流域生态系统的一个重要组成部分,独特的地理与生态区位使得巴音布鲁克草原湿地成为维系流域生态环境安全的关键因素。由于巴音布鲁克草原湿地位于高海拔、高寒地带,生态环境极为脆弱、敏感,气候变化、人类活动等干扰对其产生的影响远较一般地区的湿地要快和剧烈。近年来,在全球气候变化及人类活动双重作用下,巴音布鲁克草原湿地的景观格局发生了明显的变化。本研究根据巴音布鲁克湿地水文和植被特征建立了湿地景观分类系统,基于ENVI4.8对1998年、2006年和2014年三个不同时期的卫星影像做出预处理,提取景观格局信息并评价信息提取结果的精度。通过GIS空间分析生成景观转移矩阵,并据此分析不同斑块类型间的转化过程,之后计算得出景观格局指数,分析研究区内斑块类型水平以及景观水平上的格局特征及其时空变化规律。从湿地水文要素能直接或间接地影响景观格局的角度出发,分析研究区景观格局发生变化的水文驱动机制,揭示巴音布鲁克草原湿地景观格局变化的根本原因,以期为区域湿地资源的合理利用提供参考进而为湿地生态环境的保护提供科学依据。本文的主要结论如下：(1)1998年至2014年以来,研究区的湿地面积呈不断增加趋势,这主要得益于近年来研究区的气候朝暖湿化方向发展；沙地面积不断扩大,且速度呈现加速化,这与局部地区过度放牧导致植被破坏以及雨水冲刷有关；研究区的景观总体呈现出破碎化趋势,斑块形状变得复杂,景观内部优势度降低,异质性增加,各斑块类型的分布更为均匀,景观类型由集中变为分散。(2)研究区的植被物种丰富度与生境水深在0.01水平上呈显著负相关,相关系数达到-0.842,说明研究区的植物种类数受到生境水深的影响。在一定范围内,随着生境水位的升高,植物的种类减少,物种丰富度降低。(3)研究区的样方生物量和生境水深之间有着较大的关联性。随着生境水位的升高,植物样方的生物量呈现出先升高后降低的趋势,R2达到0.764。可能原因是随着生境水位的升高,植被获取水分及营养物质的条件得以改善,使得净初级生产力提高；当水位继续升高直至生境处于淹水状态时,植被物种丰富度的降低导致了生物量的下降。(4)水文过程是湿地景观格局变化的主要驱动因素,它可以直接作用于湿地景观,也可以通过影响湿地生态系统的物理化学过程、生物过程等间接地对其景观格局产生影响。经灰色关联分析表明,研究区的LSI、ED、SHDI以及SHEI等景观格局指数与径流量、降水量等水文要素之间有着明显的相关性。
[Abstract]:The Bayinbrook grassland wetland is developed in the Uladuz Intermountain tectonic basin on the southern slope of Tianshan Mountain. The formation of the wetland is mainly due to the high altitude cold and wet climate caused by the uplift of the middle Tianshan fold fault block in a wide range of arid areas. As an important part of the watershed ecosystem, the unique geographical and ecological location makes the Bayinbrook grassland wetland a key factor to maintain the ecological environment security of the basin. Because the Bayinbrook grassland wetland is located in the high altitude, the high cold area, the ecological environment is extremely fragile, sensitive, the climate change, the human activity and so on disturbance produces the influence to it is much faster and more intense than the general area wetland. In recent years, under the dual action of global climate change and human activities, the landscape pattern of Bayinbrook grassland wetland has changed obviously. Based on the hydrological and vegetation characteristics of Bayinbrook wetland, a wetland landscape classification system was established in this paper. Based on ENVI4.8, the satellite images of three different periods in 1998, 2006 and 2014 were preprocessed. Extract landscape pattern information and evaluate the accuracy of information extraction results. The landscape transfer matrix was generated by GIS spatial analysis, and the transformation process among different patch types was analyzed, and then the landscape pattern index was calculated. The pattern characteristics and temporal and spatial changes of patch types and landscape levels in the study area were analyzed. From the point of view that the hydrological elements of wetland can directly or indirectly affect the landscape pattern, the hydrological driving mechanism of landscape pattern change in the study area is analyzed, and the fundamental reasons for the change of landscape pattern in Bayinbrook grassland are revealed. In order to provide reference for the rational utilization of regional wetland resources and provide scientific basis for the protection of wetland ecological environment. The main conclusions of this paper are as follows: (1) since 1998 to 2014, the wetland area of the study area has been increasing, which is mainly due to the recent development of the climate in the study area towards the direction of warm and wet, and the area of sandy land has been expanding and the speed is accelerating. This is related to vegetation destruction and Rain Water erosion caused by overgrazing in local areas. The landscape in the study area showed a trend of fragmentation, the patch shape became complex, the dominance of landscape interior decreased, and the heterogeneity increased. The distribution of each patch type was more uniform, and the landscape type changed from concentration to dispersion. (2) there was a significant negative correlation between vegetation species richness and habitat water depth at 0.01 level in the study area. The correlation coefficient was -0.842, indicating that the number of plant species in the study area was affected by the water depth of habitat. In a certain range, with the increase of habitat water level, the species of plants decreased and the species richness decreased. (3) there is a great correlation between the biomass of sample square and the water depth of habitat in the study area. With the increase of water level in habitat, the biomass of plant sample increased first and then decreased, and the R2 reached 0.764. This may be due to the improvement of vegetation access to water and nutrients as the habitat water level rises, resulting in an increase in net primary productivity; when the water level continues to rise until the habitat is flooded, The decrease of vegetation species richness leads to the decrease of biomass. (4) Hydrological process is the main driving factor of wetland landscape pattern change, which can directly affect wetland landscape, but also affect the physical and chemical process of wetland ecosystem. Biological processes have an indirect effect on the landscape pattern. The grey correlation analysis shows that there is a significant correlation between the landscape pattern indices such as LSI EDV SHDI and Shei and the hydrological factors such as runoff precipitation and so on.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P901

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