摘要
β多样性是表示植物群落物种组成变化的一个重要指示因子。本研究以古尔班通古特沙漠南部为研究区域,在67个样地植被学调查基础上,首先对研究区植物群落β多样性经向和纬向的变化进行了分析,其次利用方差分解的方法分析环境变量,土壤种子库变量及空间变量对β多样性分异的贡献率,探讨沙漠植被β多样性变化机制。结果表明,β多样性在经向上由西向东物种相似性增加,物种替代速率减弱;在纬向上自北向南物种相似性降低,物种替代速率略有升高。对β多样性分异解释方面,环境变量中的30年月平均降水量等变量在沙漠植被群落分布中起着决定性的作用,土壤变量与空间变量的解释比率则相对较低,而土壤种子库变化较土壤异质性对β多样性影响更大。主环境变量、土壤变量的效应是尺度依赖的。空间结构决定的随机过程也发挥着作用。研究还发现除环境变量(含土壤变量),土壤种子库变量及空间变量外,仍有近50%的β多样性分异未能解释,表明其他环境因子和随机过程对植被的影响也较大。
β diversity is an important index characterizing composition variation of vegetation community.The southern part of Gurbantunggut Desert is taken as the study area in this paper,on the basis of vegetation survey in 67 plots,β diversity variation of vegetation community in the study area is analyzed first in longitudinal and latitudinal directions,and then the method of variance partitioning is used for analyzing contribution ratio of environment variable,soil seed bank variable and spatial variable to β diversity differentiation,discussing the mechanism of β diversity differentiation of desert vegetation.It is shown with the results that β diversity is an increase of species similarity from west to east in longitudinal direction,and the species succession rate declines;a decrease of species similarity from north to south in latitudinal direction,and the species succession rate increases slightly.Regarding interpretation of β diversity differentiation,the environment variables such as 30-year’s average monthly precipitation play a decisive role in distribution of desert vegetation community,while the interpretation ratio of soil variable and spatial variable are relative low.Comparing with soil heterogeneity,the variation of soil seed bank has a bigger impact on β diversity differentiation.The main environmental variables,soil variables effect were scale dependent.Neutral process determined by the spatial structure also plays a role.It is found out that although environment variables （including soil variable）,soil seed bank variable and spatial variable are taken into consideration,nearly 50% of β diversity differentiation cannot be interpreted,which indicates that some other environment variables and random process have impact on the variation of vegetation community.
出处
《草业学报》
CSCD
北大核心
2010年第3期29-37,共9页
Acta Prataculturae Sinica
基金
国家十一五科技支撑计划项目(2007BAC17B03)资助
关键词
Β多样性
方差分解
主轴邻矩法
古尔班通古特沙漠
β diversity
variance partitioning
principal coordinates of neighbor matrices method （PCNM）
Gurbantunggut Desert
