The relation between species diversity and ecosystem functioning is one of the most frequently discussed topics in ecology. Experiments often revealed an increase of productivity in species‐rich ecosystems. But large variations in these relationships, both on a local scale and in comparisons of sites along environmental gradients, still challenge our understanding of the role of species (with specific traits) and their interactions in ecosystems. In this study, we explored the role of species traits for ecosystem functioning. We used an individual‐based mechanistic grassland model which captures intra‐ and interspecific competition between plants for light and soil resources. We explored how the dynamics and productivity of grasslands are influenced by species traits and analyzed in a simulation study two species, which differ only in one particular trait. Our focus was on traits that determine how species can cope with resource limitations, for which we identified their relative importance for (1) individual plant growth, (2) monoculture dynamics, and (3) species mixture dynamics. We observed diverse relationships between species traits and different vegetation attributes for the different ecosystem levels. Most traits showed positive but saturating trends of increasing trait values but the variability in these relations increased in monocultures with intraspecific plant interactions and even more pronounced in mixtures with interspecific interactions. Using a process‐based grassland model, we were able to simulate overyielding even though it was not correlated with trait values or trait differences between both species. Correlations were also not found in terms of stability of vegetation dynamics. In contrast, for some traits already small differences supported the dominance of a species in the mixture in which species dynamics generally followed trade‐offs. The here presented simulation study demonstrates the use of process‐based models for analyzing trait‐productivity relationships in grasslands. Such models can complement previous approaches in empirical and theoretical biodiversity research and can help to move closer to understanding the mechanisms governing grassland dynamics.

中文翻译：

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物种性状在草地生产力中的作用

物种多样性与生态系统功能之间的关系是生态学中最常讨论的话题之一。实验通常表明，物种丰富的生态系统的生产力有所提高。但是，无论是在地方尺度上还是在沿环境梯度的地点比较中，这些关系的巨大变化仍然挑战着我们对物种（具有特定特征）的作用及其在生态系统中相互作用的理解。在这项研究中，我们探索了物种性状对生态系统功能的作用。我们使用了基于个体的机械草地模型，该模型捕获了植物之间对光和土壤资源的种内和种间竞争。我们探索了草原动态和生产力如何受到物种特征的影响，并在模拟研究中分析了两种物种，仅在一个特定特征上有所不同。我们的重点是确定物种如何应对资源限制的性状，为此我们确定了它们对于（1）单株生长，（2）单种栽培动态和（3）物种混合动态的相对重要性。我们观察到了不同生态系统级别的物种特征与不同植被属性之间的各种关系。大多数性状表现出正性但饱和的趋势，即性状值增加，但这些关系的变异性在具有种内植物相互作用的单一栽培中增加，而在具有种间相互作用的混合物中更为明显。使用基于过程的草地模型，即使它与两个物种之间的性状值或性状差异不相关，我们也能够模拟其过度产量。在植被动力学的稳定性方面也未发现相关性。相比之下，对于某些性状，很小的差异支持了物种在混合物中的优势地位，而物种动力学通常遵循权衡取舍。本文介绍的模拟研究证明了基于过程的模型在分析草地性状-生产力关系中的应用。这样的模型可以补充经验和理论上的生物多样性研究的先前方法，并可以帮助进一步了解治理草原动态的机制。本文介绍的模拟研究证明了基于过程的模型在分析草地性状-生产力关系中的应用。这样的模型可以补充经验和理论上的生物多样性研究的先前方法，并可以帮助进一步了解治理草原动态的机制。本文介绍的模拟研究证明了基于过程的模型在分析草地性状-生产力关系中的应用。这样的模型可以补充经验和理论上的生物多样性研究的先前方法，并可以帮助进一步了解治理草原动态的机制。