Focusing on individual plants to understand community scale biodiversity effects: the case of root distribution in grasslands

Spatial resource partitioning between species via differences in rooting depth is one of the main explanations for the positive biodiversity-productivity relationship. However, evidence for the importance of this mechanism is limited. This may be due to the community scale at which these interactions are often investigated. Community measures represent net outcomes of species interactions and may obscure the mechanisms underlying belowground interactions.

Here, we assess the performance of ~1700 individual plants and their heterospecific neighbours over three growing seasons in experimental grassland plots containing one, four or 16 different plant species and tested whether their performance in mixtures compared to monocultures was related to their own rooting depth vs. the rooting depth of their heterospecific neighbours.

Overall, individuals of deep-rooting species performed better in mixtures and this effect significantly increased when surrounded by more shallow-rooting speci...

基于根系深度差异实现的物种间空间资源分区，是解释生物多样性-生产力正向关系的核心机制之一。然而，支撑该机制重要性的实证证据仍较为匮乏。这一现象可能源于相关研究多以群落尺度开展：群落水平的观测仅能反映物种互作的净效应，可能会掩盖地下部种间互作背后的真实机制。

本研究依托包含1种、4种或16种植物的实验草地样地，对约1700株单株植物及其异种邻株开展了三个生长季的性能监测，并检验了相较于单作样地，混生植株的生长表现是否与其自身根系深度，以及异种邻株的根系深度存在关联。

整体而言，深根物种的单株在混生样地中生长更佳，且当周围邻株为浅根物种时，该优势效应会显著增强……