Invasive terrestrial isopods are likely to have altered leaf litter decomposition processes in North American forests, but the mechanisms underlying these alterations and the degree to which they differ among isopod species are poorly characterized. Using mixed-deciduous leaf litter microcosms, we quantified the effects of two common, invasive isopods (Oniscus asellus and Porcellio scaber) on short-term leaf litter decomposition and microbial community structure and function. Microcosms containing ground litter and a microbial inoculant were exposed to one of the two isopod species or no isopods for 21 days. Mass loss was then quantified as the change in litter dry mass after leaching, and microbial respiration was quantified as the mass of CO2 absorbed by soda lime. Litter leachates were plated on agar to quantify culturable bacterial and fungal abundance, and denaturing gradient gel electrophoresis of amplified leachate microbial DNA was used to characterize shifts in microbial community structure. Isopod presence increased litter mass loss by a modest ~ 6%, but did not affect litter microbial respiration. Bacterial abundance increased significantly in the presence of isopods, while fungal abundance was either unchanged or reduced. Overall litter microbial species richness was reduced by isopods, with O. asellus specifically reducing fungal abundance and diversity. Isopods modified the microbial community structure by suppressing four bacterial and one fungal species, while promoting growth of four other bacterial species (two unique to each isopod species) and two fungal species (one which was unique to O. asellus).

中文翻译：

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陆生等脚线虫Porcellio scaber和Asiscus asellus（甲壳纲：Isopoda）增加细菌丰度并改变叶片凋落物微观世界中的微生物群落结构：一项短期分解研究。

在北美森林中，入侵性陆足类异足动物可能已经改变了凋落物分解过程，但是这些改变的潜在机制及其在异足类物种之间的差异程度尚不明确。我们使用混合落叶落叶凋落物的缩影，量化了两种常见的侵入性等足类（Oniscus asellus和Porcellio scaber）对短期凋落物分解以及微生物群落结构和功能的影响。将含有地面凋落物和微生物接种剂的微观世界暴露于两种等足类动物之一或没有等足动物21天。然后将质量损失量化为沥滤后垃圾干质量的变化，将微生物呼吸量化为苏打石灰吸收的CO2质量。将凋落物浸出液铺在琼脂上以定量可培养的细菌和真菌的丰度，并使用扩增的浸出液微生物DNA的变性梯度凝胶电泳来表征微生物群落结构的变化。等足动物的存在使垫料质量损失增加了约6％，但不影响垫料微生物的呼吸作用。在存在等足动物的情况下，细菌的丰度显着增加，而真菌的丰度则保持不变或降低。异足动物降低了整体凋落物微生物物种的丰富度，而O. asellus则特别降低了真菌的丰度和多样性。等足类动物通过抑制四种细菌和一种真菌物种来修饰微生物群落结构，同时促进其他四种细菌（每种等足类动物具有两种独特性）和两种真菌（O所具有的一种独特性）的生长。