Data from: A tale of scale: plot but not neighbourhood tree diversity increases leaf litter ant diversity

1. Diversity of producers (e.g. plants) usually increases the diversity of associated organisms, but the scale (i.e. the spatial area of plant diversity considered) at which plant diversity acts on other taxa has rarely been studied. Most evidence for cross-taxon diversity relations come from aboveground consumers that directly interact with plants. 2. Experimental tests of plant diversity effects on elusive organisms inhabiting the leaf litter layer, which are important for nutrient cycling and decomposition, are rare. 3. Using a large tree diversity experiment, we tested whether tree diversity at the larger plot (i.e. community) or the smaller neighbourhood scale relates to the abundance, species richness, functional, and phylogenetic diversity of leaf litter ants, which are dominant organisms in brown food webs. 4. Contrary to our expectations of scale-independent positive tree diversity effects, ant diversity increased only with plot but not neighbourhood tree diversity. While the exact causal mechanisms are unclear, nest relocation or small-scale competition among ants may explain the stronger tree diversity effects at the plot scale. 5. Our results indicate that even for small and less mobile organisms in the leaf litter, effects of tree diversity are stronger at relatively larger scales. The finding emphasize the importance of diverse forest stands, in which mixing of tree species is not restricted to small patches, for supporting arthropod diversity in the leaf litter.

1. 生产者（producer，例如植物）的多样性通常会提升其伴生生物的多样性，但植物多样性对其他生物类群发挥作用的尺度（即所考量的植物多样性空间范围）却鲜有研究。跨类群多样性关系的多数证据均来自与植物直接互作的地上消费者（aboveground consumer）。
2. 针对栖息于枯落物层（leaf litter layer）、对养分循环与分解过程具有重要意义的难以观测生物的植物多样性效应的实验研究，同样十分匮乏。
3. 本研究依托大型树木多样性实验，检验更大尺度样地（即群落）或更小尺度邻域（neighbourhood scale）内的树木多样性，是否与枯落物蚂蚁的多度、物种丰富度（species richness）、功能多样性（functional diversity）及系统发育多样性（phylogenetic diversity）相关——这类蚂蚁是腐食食物网（brown food webs）中的优势类群。
4. 本研究最初预期树木多样性效应不受尺度影响且呈正向，但结果却与之相悖：蚂蚁多样性仅随样地尺度的树木多样性提升，而非邻域尺度的树木多样性。尽管确切的因果机制尚不明确，但蚂蚁间的小型竞争或巢址迁移，或可解释样地尺度下更强的树木多样性效应。
5. 本研究结果表明，即便对于枯落物层中体型微小、移动性较弱的生物而言，树木多样性的效应在相对更大的尺度下也更为显著。该发现强调了多样化林分（其树木物种混交不受限于小型斑块）对于维持枯落物层节肢动物多样性的重要意义。