Idiosyncrasy and overdominance in the structure of natural communities of arbuscular mycorrhizal fungi: is there a role for stochastic processes?
Idiosyncrasy and overdominance in the structure of natural communities of arbuscular mycorrhizal fungi: is there a role for stochastic processes?
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DOI：
10.1111/j.1365-2745.2009.01622.x
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发表时间：
2010-03-01
影响因子：
5.5
通讯作者：
Fitter, Alastair H.
中科院分区：
文献类型：
--
作者：
Dumbrell, Alex J.;Nelson, Michaela;Fitter, Alastair H.
1.大多数物种丰度模式的研究集中在显着的大型生物，而微生物群落仍然相对不足。考虑到微生物的功能重要性和高度多样性，这种偏见是一个令人担忧的问题。我们确定是否观察到一个共同的物种丰度分布（SAD）在社区的一个广泛的土壤微生物，球囊菌门或丛枝菌根（AM）真菌。利用分子生物学技术，我们集中采样的AM真菌群落的林地-草地交错带在约克郡，英国。观察到的物种丰度进行了比较，描述SAD的理论模型。我们还以类似的方式重新分析了32个以前发表的数据集。所有AM真菌群落的物种多度分布均符合对数正态分布和断棒模型。然而，这些模型一致和显着低估了最丰富的AM真菌taxon. We发现，AM真菌群落通常是由一个单一的类群占主导地位，平均40%的总丰度内的社会。系统发育分析表明，各群落中AM真菌的优势类群不同，不是广布的.我们的结论是一个共同的社区结构是存在于AM真菌群落从不同的生境。对数正态和破棒模型的拟合表明，这些社区的生态位分化结构的影响。然而，持续观察到的超优势表明，当地的适应和随机过程也可能在构建这些社区中发挥重要作用，我们提出了一个机制来解释超优势AM真菌社区。合成.本文应用生态学模型从大型生物的研究微生物群落。这项研究的结果表明，一个共同的对数正态SAD很可能被观察到在微生物和大型类群。然而，由于微生物生物学的独特性，一些显著的差异，如严重的超优势，可能会导致独特的结构中的微生物群落。这项研究不仅强调，在第一个近似值中，微生物群落遵循类似的过程，并具有与大型生物相似的模式，而且还需要大规模的微生物数据集，如果我们要了解调节全球生物多样性的模式和过程。
1. Most studies of species abundance patterns focus on conspicuous macroorganisms while microbial communities remain relatively understudied. This bias is a concern given the functional importance and high diversity of microbes.2. We determine whether a common species abundance distribution (SAD) is observed in communities of a widespread group of soil microbes, the Glomeromycota or arbuscular mycorrhizal (AM) fungi. Using molecular techniques, we intensively sampled the AM fungal community of a woodland-grassland ecotone in Yorkshire, UK. Observed species abundances were compared to theoretical models describing SADs. We also reanalysed 32 previously published data sets in a similar manner.3. Species abundance distributions in all the AM fungal communities fitted both lognormal and broken-stick models. However, these models consistently and significantly underpredicted the abundance of the most abundant AM fungal taxon. We found that AM fungal communities are typically dominated by a single taxon; representing on average 40% of total abundance within the community. Phylogenetic analysis of the most abundant taxa across data sets showed that the dominant AM fungal type in each community was different and not a widespread generalist.4. We conclude that a common community structure is present in AM fungal communities from different habitats. The fit to log-normal and broken-stick models suggests the influence of niche differentiation structuring these communities. However, the consistently observed overdominance indicates that local adaptation and stochastic processes may also play important roles in structuring these communities, and we propose a mechanism to explain overdominance in AM fungal communities.5. Synthesis. This paper applies ecological models derived from studies on larger organisms to microbial communities. Results from this study suggest that a common log-normal SAD is likely to be observed across both microbial and macro taxa. However, due to the distinctive features of microbial biology, some noticeable differences, such as heavy overdominance, may lead to unique structures in microbial communities. This research not only highlights that, to a first approximation, microbial communities follow similar processes and have similar patterns to those of macroorganisms, but also the need for large-scale microbial data sets, if we are to understand the patterns and processes regulating global biodiversity.