Department of Ecology and Ecosystem Modelling, University of Potsdam, Potsdam, Germany.
Oecologia. 2010 Nov;164(3):665-77. doi: 10.1007/s00442-010-1688-z. Epub 2010 Jul 9.
Effects of plant community diversity on ecosystem processes have recently received major attention. In contrast, effects of species richness and functional richness on individual plant performance, and their magnitude relative to effects of community composition, have been largely neglected. Therefore, we examined height, aboveground biomass, and inflorescence production of individual plants of all species present in 82 large plots of the Jena Experiment, a large grassland biodiversity experiment in Germany. These plots differed in species richness (1-60), functional richness (1-4), and community composition. On average, in more species-rich communities, plant individuals grew taller, but weighed less, were less likely to flower, and had fewer inflorescences. In plots containing legumes, non-legumes were higher and weighed more than in plots without legumes. In plots containing grasses, non-grasses were less likely to flower than in plots without grasses. This indicates that legumes positively and grasses negatively affected the performance of other species. Species richness and functional richness effects differed systematically between functional groups. The magnitude of the increase in plant height with increasing species richness was greatest in grasses and was progressively smaller in legumes, small herbs, and tall herbs. Individual aboveground biomass responses to increasing species richness also differed among functional groups and were positive for legumes, less pronouncedly positive for grasses, negative for small herbs, and more pronouncedly negative for tall herbs. Moreover, these effects of species richness differed strongly between species within these functional groups. We conclude that individual plant performance largely depends on the diversity of the surrounding community, and that the direction and magnitude of the effects of species richness and functional richness differs largely between species. Our study suggests that diversity of the surrounding community needs to be taken into account when interpreting drivers of the performance of individual plants.
植物群落多样性对生态系统过程的影响最近受到了极大关注。相比之下，物种丰富度和功能丰富度对单个植物表现的影响，以及它们与群落组成的影响相对大小，在很大程度上被忽视了。因此，我们研究了德国一个大型草地生物多样性实验——耶拿实验中 82 个大样地中所有物种的个体植物的高度、地上生物量和花序产量。这些样地在物种丰富度（1-60）、功能丰富度（1-4）和群落组成方面存在差异。平均而言，在物种更丰富的群落中，植物个体长得更高，但重量更轻，开花可能性更小，花序更少。在含有豆科植物的样地中，非豆科植物比不含豆科植物的样地更高、更重。在含有禾本科植物的样地中，非禾本科植物比不含禾本科植物的样地开花可能性更小。这表明豆科植物对其他物种的表现有积极影响，而禾本科植物有负面影响。物种丰富度和功能丰富度的影响在功能组之间存在系统差异。植物高度随物种丰富度增加而增加的幅度在禾本科中最大，在豆科、小草本和高草本中逐渐减小。地上生物量对物种丰富度增加的响应也因功能组而异，豆科植物呈正响应，禾本科植物的响应不那么明显，小草本植物呈负响应，高草本植物的响应更明显。此外，这些物种丰富度的影响在这些功能组内的物种之间差异很大。我们得出的结论是，单个植物的表现在很大程度上取决于周围群落的多样性，而物种丰富度和功能丰富度的方向和大小在很大程度上因物种而异。我们的研究表明，在解释单个植物表现的驱动因素时，需要考虑周围群落的多样性。
