Managed grasslands play an important role in European landscapes. They are often characterized by a high productivity and a low variability of traits between species. Though the relationship between traits and productivity has been investigated by various field studies, insight is still lacking in understanding the role of species trait variability.

This study combines species-specific traits with grassland modelling to investigate how variability in grassland species influences grassland dynamics and functioning. Based on a field experiment in Central-Eastern Germany, we parameterized an individual-based grassland model. We analyzed simulations of grasslands with four grass species and compared results with observed vegetation attributes (e.g., productivity, species composition and vegetation height). In a next step, we systematically added and removed interspecific variability in traits regarding (a) photosynthetic capacity, (b) mortality, (c) plant geometry, and (d) seed establishment and investigated the effect on different grassland attributes such as leaf area index and gross primary productivity.

We found that grassland dynamics are markedly influenced by species-specific differences in traits. Annual productivity was mostly driven by traits describing a plant's photosynthetic capacity and plant geometry. Some grassland attributes (like leaf area index and gross primary productivity) showed to be more sensitive to variability in plant geometric traits and traits describing seed establishment. Simulations with similar species traits resulted in a more balanced species composition, underlining the role of trait variability for interspecific competition processes. However, we showed here that different trait categories affect different attributes and functions of grasslands.

We demonstrated in this study that individual-based models can help to gain a deeper understanding of the relative importance of plant traits on community dynamics and ecosystem functions of grasslands.

受管理的草原在欧洲景观中扮演着重要角色。它们通常以高生产率和物种之间性状的低变异性为特征。尽管已通过各种田间研究调查了性状与生产力之间的关系，但仍缺乏了解物种性状变异性作用的见识。

这项研究将特定物种的特征与草地模型相结合，以研究草地物种的变异性如何影响草地的动态和功能。基于在德国中东部的野外实验，我们对基于个体的草地模型进行了参数化。我们分析了四种草种的草地模拟，并将结果与​​观察到的植被属性（例如生产力，物种组成和植被高度）进行了比较。在下一步中，我们系统地添加和删除了与以下各项有关的性状的种间变异性：（a）光合能力，（b）死亡率，（c）植物的几何形状和（d）种子的建立，并研究了其对不同草地属性（如叶面积）的影响指数和初级生产力总额。

我们发现草原动态受到性状的特定物种差异的显着影响。年生产力主要由描述植物光合能力和植物几何形状的特征驱动。一些草地属性（如叶面积指数和总初级生产力）显示出对植物几何性状和描述种子形成的性状的变异更敏感。具有相似物种特征的模拟导致更平衡的物种组成，突显了特征变异性在种间竞争过程中的作用。但是，我们在这里表明，不同的性状类别会影响草原的不同属性和功能。

我们在这项研究中证明，基于个体的模型可以帮助更深入地了解植物性状对草原社区动态和生态系统功能的相对重要性。