不同尺度下艾比湖典型植物群落功能多样性和系统发育多样性研究

Multi-scale Analysis on Functional Diversity and Phylogenetic Diversity of Typical Plant Community in Ebinur Lake

运用功能多样性和系统发育多样性综合探讨群落构建机制是近年来生态学的研究热点。以艾比湖流域干旱荒漠生态系统为研究对象,结合环境因子,分析不同尺度下系统发育和功能性状结构的变化趋势,进而揭示艾比湖流域干旱荒漠区植物群落构建机制。结果表明,(1)叶片宽度、叶片厚度和叶片干物质含量具有显著的系统发育信号(P<0.05),其它功能性状未检测到明显的系统发育信号。(2)不同尺度下系统发育结构均趋向于发散,表明竞争排斥作用在植物分布占优势地位,而功能结构均趋向于聚集,生境过滤作用占据主导。(3)净亲缘关系指数(NRI)、谱系丰富度(PD)和功能丰富度(FRic)在5 m×5 m尺度显著不同于其他尺度。标准化的群落平均配对性状距离(trait SES(MPD))在所有尺度下统计差异均不显著,最近性状距离(trait SES(MNTD))和最近亲缘关系指数(NTI)在5 m×5 m尺度和50 m×50 m尺度差异显著。植物群落整体受生态位作用影响更强,且在大尺度上(50 m×50 m)环境过滤在群落构建中起主导作用。(4)含盐量对系统发育指数和功能性状指数均有显著影响(P<0.05),土壤有机质和硝态氮含量均对功能性状指数有显著影响,而铵态氮含量对系统发育指数有显著影响。土壤含盐量以及氮含量作为主要的环境筛影响着艾比湖流域植物群落构建过程。

It is a core question in ecology to explore the mechanisms of community assembly by using functional diversity and phylogenetic diversity in recent years.In present study,we analyzed the changes of phylogeny and functional traits structure along different scales of plant communities in the desert area of Ebinur Lake basin,combined with environmental variables.We aim to reveal the mechanism of plant community assembly in the arid desert area.The results showed that:(1)The leaf width,leaf thickness and leaf dry matter content(P<0.05)had significant phylogenetic signal,whereas other functional traits did not have strong phylogenetic conservatism.(2)At different scales,the community phylogenetic structure was overdispersion,implying that the distribution of plants in desert area was mainly determined competitive exclusion,while the functional structure was clustering,indicating that the habitat filtering had dominate role.(3)The net relatedness index(NRI),pedigree richness(PD)and functional richness(FRic)at 5 m×5 m scale were significantly different from other scales.The mean pairwise nodal distance(MPD)were not significantly different among all scales,while the mean nearest taxa nodal distance(MNTD)and nearest taxon index(NTI)significantly differed between the 5 m×5 m scale and 50 m×50 m scale.The plant community was strongly affected by niche process,and environmental filtering played a primary role in community assembly at large scale(50 m×50 m).And(4)the salt content had significant effects on the phylogenetic index and the functional trait index(P<0.05);the soil organic matter and nitrate nitrogen content had significant effect on the functional trait index,while ammonium nitrogen content had significant effect on the phylogenetic index.In conclusion,the soil salinity and nitrogen content as the main environmental sieve significantly affected the assembly process of desert plant community in the Ebinur lake basin.