摘要
为探究半干旱区湿地-干草原生态交错带的边界及影响其植被空间分布格局的主要环境因子,以宁夏哈巴湖荒漠湿地自然保护区内的四儿滩湿地为例,采用样线调查法获得植被与环境数据：首先利用游动分割窗技术对研究区进行交错带定量判定,将其分为旱生带、交错带、湿生带并计算沿不同生境梯度β多样性变化趋势;然后,采用典范对应分析法对研究区植被数据矩阵和环境数据矩阵进行排序,同时进行排序轴与土壤环境因子间的秩相关分析。结果表明：采用游动分割窗技术判定四儿滩湿地-干草原交错带最适窗口宽度为6~8个样方;不同生境带β多样性指数存在明显梯度变化;典范对应分析结果显示,植被在CCA排序图上的分布与游动分割窗技术的划分结果相吻合,含盐量（质量分数）、含水量是影响四儿滩植被空间分布的主要环境因子,对含盐量和含水量有较高适应值的物种集中分布于土壤盐渍化严重的湿生带。研究结果将为四儿滩湿地的恢复和保护提供参考。
[Background] Siertan Wetland is the largest wetland of Habahu Desert Wetland Nature Reserve in Yanchi County,Ningxia Autonomous Region. Through the annual vegetation investigation which has been carried out for 11 years,we found that the area of Siertan Wetland is shrinking year by year. Many researchers concluded that the ecotone is very sensitive to the change of environment,thus it can be used to predict the change of the ecological environment in advance. This study is to quantitatively determine the ecological ecotone boundary and the main environmental factors that affect the spatial distribution pattern of the species. [Methods] Firstly we used moving split-window technique to quantitatively determine the ecological ecotone. Use of the moving split-window technique required that：we chose an appropriate even number of representative samples as a whole window,then divided the whole window in half and calculated their dissimilarity coefficient. We continuously moved the window right to the next sampling point and repeated the operation above again,until the right window reached the final sampling points. We then draw a scatter diagram of the dissimilarity coefficient changes by quadrats. Further,according to the result of determination we divided the research area into wetland regions,ecotone and arid region,and analyzed characteristics of beta diversity in the three different habitats of the four different sample lines. Finally,Canonical Correspondence Analysis（ CCA） was used to determine which environmental factors contributed most to the distribution of the vegetation. [Results]The results showed that ecotone was determined clearly by moving split-window technique under 6- 8quadrats,the optimal window width of east transect line was 6 quadrates,the optimal window width of west,south and north transect line was 8 quadrates. Beta diversity index showed significant differences in different habitats. The result of CCA indicated that the total salt content and moisture content were the main environmental factors that affected the vegetation distribution in Siertan Wetland. The correlation of the two environmental factors and the first species axis were respectively 0. 868 4 and 0. 917 0,the correlation of the two environmental factors and the first environment axis were respectively 0. 841 6 and0. 891 4. [Conclusions] According to the dimension of investigatory scale and the visibility of ecotone transitivity,appropriate window width can be chosen especially in the selection of appropriate smallest window width. Species with higher fitness for total salt content and moisture content variability are mainly distributed in wet region with serious soil salinization. The results of the study will provide valuable reference for Siertan Wetland＇s restoration and protection. The future work of Habahu Nature Reserve administration should be focused on protecting Siertan Wetland from human being destruction,ensuring adequate water supply, improving the salinization land, and maintaining plant species diversity in wetland.
出处
《中国水土保持科学》
CSCD
北大核心
2016年第6期70-77,共8页
Science of Soil and Water Conservation
基金
"十三五"国家重点研发计划"生态畜牧业与沙化草地治理技术集成及产业示范"(2016YFC0500908)
国家自然科学基金"半荒漠湿地植被群落时空分布特征研究"(30771764)
国家林业局荒漠化定位监测项目"盐池荒漠化定位监测"(660550)
关键词
四儿滩湿地
生态交错带
游动分割窗技术
典范对应分析
Siertan Wetland
ecotone
moving split-window technique
canonical correspondence analysis
