Taiwan International Graduate Program (TIGP)-Earth System Science Program, Academia Sinica, Taipei, 115, Taiwan.
Taiwan International Graduate Program (TIGP)-Earth System Science Program, National Central University, Taoyuan, 320, Taiwan.
FEMS Microbiol Ecol. 2022 Jun 17;98(6). doi: 10.1093/femsec/fiac058.
An ecosystem function is suggested to be more sensitive to biodiversity loss (i.e. low functional redundancy) when focusing on specific-type functions than broad-type functions. Thus far, specific-type functions have been loosely defined as functions performed by a small number of species (facilitative species) or functions involved in utilizing complex substrates. However, quantitative examination of functional specificity remains underexplored. We quantified the functional redundancy of 33 ecosystem functions in a freshwater system from 76 prokaryotic community samples over 3 years. For each function, we used a sparse regression model to estimate the number of facilitative Amplicon Sequence Variants (ASVs) and to define taxon-based functional specificity. We also used Bertz structural complexity to determine substrate-based functional specificity. We found that functional redundancy increased with the taxon-based functional specificity, defined as the proportion of facilitative ASVs (= facilitative ASV richness/facilitative ASV richness + repressive ASV (ASVs reducing functioning) richness). When using substrate-based functional specificity, functional redundancy was influenced by Bertz complexity per se and by substrate acquisition mechanisms. Therefore, taxon-based functional specificity is a better predictive index for evaluating functional redundancy than substrate-based functional specificity. These findings provide a framework to quantitatively predict the consequences of diversity losses on ecosystem functioning.
与关注广谱功能相比，聚焦于特定类型功能时，生态系统功能被认为对生物多样性丧失（即功能冗余度低）更为敏感。到目前为止，特定类型的功能被松散地定义为少数物种（促进物种）执行的功能或涉及利用复杂基质的功能。然而，功能特异性的定量研究仍未得到充分探索。我们在三年内从 76 个原核生物群落样本中量化了淡水系统中 33 个生态系统功能的功能冗余。对于每个功能，我们使用稀疏回归模型来估计促进扩增子序列变异（ASV）的数量，并定义基于分类群的功能特异性。我们还使用 Bertz 结构复杂性来确定基于基质的功能特异性。我们发现，功能冗余性随着基于分类群的功能特异性的增加而增加，该特异性定义为促进性 ASV 的比例（=促进性 ASV 丰富度/促进性 ASV 丰富度+抑制性 ASV（减少功能的 ASV）丰富度）。当使用基于基质的功能特异性时，功能冗余性受到 Bertz 复杂性本身以及基质获取机制的影响。因此，基于分类群的功能特异性是评估功能冗余性的更好预测指标，而不是基于基质的功能特异性。这些发现为定量预测多样性丧失对生态系统功能的影响提供了一个框架。
