Abstract Ecosystem functioning is affected positively by increased biodiversity, through complementary functions of multiple species or because high-functioning species are more likely in a species-rich community. Genetic diversity is one level of biodiversity that has been shown to positively affect ecosystem functioning. Whether the genetic diversity of a key decomposer species affects decomposition processes, and ecosystem functioning in general, is still unknown. We compared low and high genetic diversity assemblages of the earthworm Dendrobaena octaedra in two different experiments: using microcosms containing a simple community of other decomposer animals (some nematodes and other microfauna) and using microcosms with a more complex community, including also another earthworm species, diverse microarthropod fauna and enchytraeid worms. We studied the soil decomposition activity through measurements of mineral nitrogen and CO2-production. In addition, the wellbeing of the earthworms was followed by determining their biomass, cocoon production, mortality and gene expression. Very few differences between low and high diversity microcosms were found, often in only one of the years studied. When differences were found, these depended on which genotype was present in the low diversity treatment. Our results suggest it is not genetic diversity per se, but specific genotypes of key decomposer species that can affect ecosystem functioning.

中文翻译：

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蚯蚓遗传多样性对分解和生态系统功能的影响

摘要 生态系统功能受到生物多样性增加、多种物种功能互补或高功能物种更有可能出现在物种丰富的群落中的积极影响。遗传多样性是一种已被证明对生态系统功能产生积极影响的生物多样性水平。关键分解者物种的遗传多样性是否会影响分解过程和生态系统的总体功能，仍然未知。我们在两个不同的实验中比较了蚯蚓石斛的低和高遗传多样性组合：使用包含其他分解动物（一些线虫和其他微型动物）的简单群落的微观世界，以及使用具有更复杂群落的微观世界，还包括另一种蚯蚓物种，多样的微节肢动物群和 enchytraeid 蠕虫。我们通过测量矿物氮和二氧化碳的产生来研究土壤分解活动。此外，通过确定蚯蚓的生物量、茧产量、死亡率和基因表达来跟踪蚯蚓的健康​​状况。发现低多样性和高多样性微观世界之间的差异很少，通常只在研究的一年中发现。当发现差异时，这取决于低多样性处理中存在哪种基因型。我们的结果表明，影响生态系统功能的不是遗传多样性本身，而是关键分解者物种的特定基因型。发现低多样性和高多样性微观世界之间的差异很少，通常只在研究的一年中发现。当发现差异时，这取决于低多样性处理中存在哪种基因型。我们的结果表明，影响生态系统功能的不是遗传多样性本身，而是关键分解者物种的特定基因型。发现低多样性和高多样性微观世界之间的差异很少，通常只在研究的一年中发现。当发现差异时，这取决于低多样性处理中存在哪种基因型。我们的结果表明，影响生态系统功能的不是遗传多样性本身，而是关键分解者物种的特定基因型。