Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom.
PLoS One. 2010 Sep 7;5(9):e12604. doi: 10.1371/journal.pone.0012604.
Individuals and not just species are key components of biodiversity, yet the relationship between intraspecific diversity and ecosystem functioning in microbial systems remains largely untested. This limits our ability to understand and predict the effects of altered genetic diversity in regulating key ecosystem processes and functions. Here, we use a model fungal system to test the hypothesis that intraspecific genotypic richness of Paxillus obscurosporus stimulates biomass and CO(2) efflux, but that this is dependent on nitrogen supply. Using controlled experimental microcosms, we show that populations containing several genotypes (maximum 8) of the fungus had greater productivity and produced significantly more CO(2) than those with fewer genotypes. Moreover, intraspecific diversity had a much stronger effect than a four-fold manipulation of the carbon:nitrogen ratio of the growth medium. The effects of intraspecific diversity were underpinned by strong roles of individuals, but overall intraspecific diversity increased the propensity of populations to over-yield, indicating that both complementarity and selection effects can operate within species. Our data demonstrate the importance of intraspecific diversity over a range of nitrogen concentrations, and the need to consider fine scale phylogenetic information of microbial communities in understanding their contribution to ecosystem processes.
个体而非仅仅是物种，是生物多样性的关键组成部分，然而微生物系统中种内多样性与生态系统功能之间的关系在很大程度上仍未经检验。这限制了我们理解和预测改变遗传多样性对调节关键生态系统过程和功能的影响的能力。在这里，我们使用一个模型真菌系统来检验这样一个假设，即 Paxillus obscurosporus 的种内基因型丰富度会刺激生物量和 CO(2) 排放，但这取决于氮供应。使用受控的实验微宇宙，我们表明，含有几种基因型（最多 8 种）的真菌种群比含有较少基因型的种群具有更高的生产力，并且产生的 CO(2) 显著更多。此外，种内多样性的影响比生长介质碳氮比的四倍操纵要大得多。种内多样性的影响是由个体的强烈作用支撑的，但总体而言，种内多样性增加了种群过度产生的倾向，表明互补和选择效应都可以在物种内发挥作用。我们的数据表明，在一系列氮浓度下，种内多样性的重要性，并且需要考虑微生物群落的精细尺度系统发育信息，以了解它们对生态系统过程的贡献。
