Data from: Diversity in form and function: vertical distribution of soil fauna mediates multidimensional trait variation

1. It has been widely recognized that species show extensive variation in form and function. Based on species' attributes they can be positioned along major axes of variation, which are often defined by life history traits, such as number of offspring, age at maturity or generation time. Less emphasis has been given in this respect to tolerance traits, especially to resistance to abiotic stress conditions, which often determine community (dis)assembly and distribution. 2. Soil fauna species distribution is governed to a large extent by environmental conditions that filter communities according to functional traits, such as abiotic stress-tolerance, morphology, and body size. Trait-based approaches have been successfully used to predict soil biota responses to abiotic stress. It remains unclear, though, how these traits relate to life history traits that determine individual performance, i.e., reproduction and survival. 3. Here, we analyze patterns in multidimensional trait distribution of dominant groups of soil fauna, i.e., Isopoda, Gastropoda and Collembola, known to be important to the functioning of ecosystems. We compiled trait information from existing literature, trait databases and supplementary measurements. We looked for common patterns in major axes of trait variation and tested if vertical distribution of species in the soil explained trait variation based on three components of trait diversity (trait richness, evenness and divergence). 4. Our results showed that two to three axes of variation structured the trait space of life history and tolerance traits in each of the taxonomic groups, and that vertical distribution in soil explained the main axis of trait variation. We also found evidence of environmental filtering on soil fauna along the vertical soil distribution, with lower trait richness and trait divergence in soil-dwelling than in surface-living species. 5. Our study was partially limited by the lack of detailed trait measurements for the selected taxonomic groups. In this regard, there is an urgent need for standardized trait databases across invertebrate groups to improve trait-based diversity analysis and fill gaps in the mechanistic understanding behind trait distribution, trait filtering and the link with species fitness and performance.

1. 物种在形态与功能上存在广泛变异，这一点已得到学界广泛认可。根据物种的属性特征，可将其置于主要的变异轴上，而这些变异轴通常由生活史性状（如后代数量、成熟年龄或世代时间）所定义。然而，针对耐受性性状的相关研究相对较少，尤其是对非生物胁迫抗性的研究，而这类性状往往决定了群落的组装（或解体）与物种分布。2. 土壤动物群的分布在很大程度上受环境条件调控，环境会依据功能性状对群落进行过滤，例如非生物胁迫耐受性、形态特征以及体型大小。基于性状的研究方法已被成功用于预测土壤生物对非生物胁迫的响应，但目前仍不清楚这些功能性状与决定个体生存与繁殖表现的生活史性状之间存在何种关联。3. 本研究针对三类对生态系统功能至关重要的优势土壤动物类群——等足目（Isopoda）、腹足纲（Gastropoda）与弹尾纲（Collembola）的多维性状分布模式展开分析。我们从已发表文献、性状数据库以及补充测量数据中收集了相关性状信息，旨在探寻性状变异的主要轴向上的共性模式，并基于性状多样性的三个维度（性状丰富度、均匀度与分异度），检验土壤中物种的垂直分布是否可以解释性状变异。4. 研究结果显示，在每个分类类群中，2至3条变异轴构成了生活史性状与耐受性性状的性状空间结构；同时土壤中的垂直分布能够解释性状变异的主要轴。此外，我们还发现沿土壤垂直分布梯度存在对土壤动物群的环境过滤现象：营土壤栖息的物种的性状丰富度与分异度均低于地表栖息物种。5. 本研究存在一定局限性，即所选分类类群的详细性状测量数据存在缺失。就此而言，亟需建立针对无脊椎动物类群的标准化性状数据库，以优化基于性状的多样性分析，填补我们在性状分布、性状过滤机制以及其与物种适合度和个体表现之间关联的认知空白。