Gammal Johanna, Hewitt Judi, Norkko Joanna, Norkko Alf, Thrush Simon
Tvärminne Zoological Station University of Helsinki Hangö Finland.
National Institute of Water and Atmospheric Research Hamilton New Zealand.
Ecol Evol. 2020 Aug 20;10(19):10395-10407. doi: 10.1002/ece3.6696. eCollection 2020 Oct.
The biodiversity crisis has increased interest in understanding the role of biodiversity for ecosystem functioning. Functional traits are often used to infer ecosystem functions to increase our understanding of these relationships over larger spatial scales. The links between specific traits and ecosystem functioning are, however, not always well established. We investigated how the choice of analyzing either individual species, selected modalities, or trait combinations affected the spatial patterns observed on a sandflat and how this was related to the natural variability in ecosystem functioning. A large dataset of 400 benthic macrofauna samples was used to explore distribution patterns. We hypothesized that (1) if multiple species (redundancy) represent a trait combination or a modality their spatial patterns would be smoothed out, and (2) the lost spatial variability within a trait combination or modality, due to the smoothing effect, would potentially affect their utility for predicting ecosystem functioning (tested on a dataset of 24 samples). We predicted that species would show heterogeneous small spatial patterns, while modalities and trait combinations would show larger and more homogeneous patterns because they would represent a collection of many distributions. If modalities and trait combinations are better predictors of ecosystem functioning than species, then the smoother spatial patterns of modalities and trait combinations would result in a more homogeneous landscape of ecosystem function and the number of species exhibiting specific traits would provide functional redundancy. Our results showed some smoothing of spatial patterns progressing from species through modalities to trait combinations, but generally spatial patterns reflected a few dominant key species. Moreover, some individual modalities and species explained more or equal proportions of the variance in the ecosystem functioning than the combined traits. The findings thus suggest that only some spatial variability is lost when species are combined into modalities and trait combinations and that a homogeneous landscape of ecosystem function is not likely.
生物多样性危机激发了人们对理解生物多样性在生态系统功能中所起作用的兴趣。功能性状常被用于推断生态系统功能，以增进我们在更大空间尺度上对这些关系的理解。然而，特定性状与生态系统功能之间的联系并非总是十分明确。我们研究了分析单个物种、选定模态或性状组合的选择如何影响在潮滩上观察到的空间格局，以及这与生态系统功能的自然变异性有何关联。利用一个包含400个底栖大型动物样本的大型数据集来探索分布格局。我们假设：（1）如果多个物种（冗余）代表一个性状组合或一种模态，它们的空间格局将会被平滑化；（2）由于平滑效应，性状组合或模态内丧失的空间变异性可能会影响它们在预测生态系统功能方面的效用（在一个包含24个样本的数据集上进行测试）。我们预测，物种会呈现出异质性的小尺度空间格局，而模态和性状组合会呈现出更大且更均匀的格局，因为它们代表了许多分布的集合。如果模态和性状组合比物种更能预测生态系统功能，那么模态和性状组合更平滑的空间格局将导致生态系统功能的景观更加均匀，并且表现出特定性状的物种数量将提供功能冗余。我们的结果表明，从物种到模态再到性状组合，空间格局存在一定程度的平滑，但总体而言，空间格局反映了少数几个占主导地位的关键物种。此外，一些单个的模态和物种解释了生态系统功能中比组合性状更多或相等比例的方差。因此，研究结果表明，当物种被组合成模态和性状组合时，只有部分空间变异性会丧失，而且不太可能出现生态系统功能的均匀景观。
