Biodiversity generally increases productivity in ecosystems; however, this is mediated by the specific functional traits that come with biodiversity loss or gain and how these traits interact with environmental conditions. Most biodiversity studies evaluate the effects of species richness alone, despite our increasing understanding that intraspecific diversity can have equally strong impacts. Here, we manipulate both species richness and intraspecific richness (i.e., number of distinct strains) in marine diatom communities to explicitly test the relative importance of species and strain richness for biomass and trait diversity in six distinct temperature/nutrient environments. We show that species and strain richness both have significant effects on biomass and growth rates, but more importantly, they interact with each other, indicating that cross‐species diversity effects depend on within‐species diversity and vice versa. This intertwined relationship thus calls for more integrative approaches quantifying the relative importance of distinct biodiversity components and environmental context on ecosystem functioning.

中文翻译：

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物种丰富度和种内变异交互影响海洋硅藻群落功能

生物多样性通常会提高生态系统的生产力；然而，这是由生物多样性丧失或增加带来的特定功能特征以及这些特征如何与环境条件相互作用所介导的。尽管我们越来越认识到种内多样性可以产生同样强大的影响，但大多数生物多样性研究仅评估物种丰富度的影响。在这里，我们操纵海洋硅藻群落中的物种丰富度和种内丰富度（即不同菌株的数量），以明确测试六种不同温度/营养环境中物种和菌株丰富度对生物量和性状多样性的相对重要性。我们表明，物种和菌株丰富度都对生物量和生长率有显着影响，但更重要的是，它们相互作用，表明跨物种多样性效应取决于物种内多样性，反之亦然。因此，这种相互交织的关系需要采取更加综合的方法来量化不同生物多样性组成部分和环境背景对生态系统功能的相对重要性。