Data from: Biodiversity-ecosystem function relationships change through primary succession

Ecologists traditionally use environmental parameters to predict successional shifts in compositional characteristics of local species assemblages (environmental control). Another important focus in ecology is to understand functional roles of species assemblages in determining local environmental properties (diversity control). Then, the question emerges: which is the cause, and which is the consequence? To clarify the causal relationships between species assemblages and environmental properties, we focused on seral changes in species/functional diversity of vascular plants in tundra ecosystems of the High Arctic. We found that, although species richness was influenced by soil properties in the earlier stages of primary succession, the causalities were reversed in the later stages. We also found functional differentiation among coexisting species in the later stage, suggesting that the ‘complementarity effect’ of diversity on ecosystem functions likely increased with ecosystem development through time. By contrast, particular species had little disproportional influence on soil properties, suggesting that the ‘selection effect’ as an alternative mechanism was less important. This result was likely attributed to the importance of facilitation in the marginal High Arctic environment. Plant–microsite associations are shaped by feedback mechanisms and therefore, neither plant nor microsite is a single absolute predictor of the other. Although our observational study has limitations, we demonstrates a possibility that the relative magnitude of the influence of one on the other can change in the process of succession, emphasizing that the causalities underlying biodiversity–ecosystem function relationships change through succession.

生态学家传统上借助环境参数预测局地物种集合(Species Assemblages)组成特征的演替偏移，即环境调控(Environmental Control)研究范式。生态学领域另一重要研究方向为解析物种集合在调控局地环境属性中发挥的功能作用，即多样性调控(Diversity Control)研究范式。由此衍生出一个核心问题：二者何为因，何为果？为厘清物种集合与环境属性间的因果关系，本研究聚焦于高北极地区苔原生态系统中维管植物(Vascular Plants)的物种/功能多样性演替动态。研究发现：尽管在原生演替的早期阶段，物种丰富度受土壤属性调控，但在演替后期，二者的因果关系发生逆转。本研究同时发现，演替后期共存物种间存在功能分化，这表明多样性对生态系统功能的‘互补效应(Complementarity Effect)’可能随生态系统的长期发育而增强。相较而言，特定物种对土壤属性并未表现出显著的非均衡影响，这意味着作为另一作用机制的‘选择效应(Selection Effect)’的重要性相对较低。该结果可能归因于促进作用(Facilitation)在高北极边缘生境中的核心地位。植物-微生境(Microsite)关联由反馈机制塑造，因此二者均无法单独作为对方的绝对预测因子。尽管本观测研究存在一定局限性，但我们的结果揭示了一种可能性：二者间的相对影响强度可随演替过程发生动态变化，同时强调了生物多样性-生态系统功能关系背后的因果机制会随演替进程发生改变。