Fichtner Andreas, Härdtle Werner, Li Ying, Bruelheide Helge, Kunz Matthias, von Oheimb Goddert
Leuphana University of Lüneburg, Institute of Ecology, Scharnhorststr. 1, 21335, Lüneburg, Germany.
Martin Luther University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, 06108, Halle (Saale), Germany.
Ecol Lett. 2017 Jul;20(7):892-900. doi: 10.1111/ele.12786. Epub 2017 Jun 14.
Studies on tree communities have demonstrated that species diversity can enhance forest productivity, but the driving mechanisms at the local neighbourhood level remain poorly understood. Here, we use data from a large-scale biodiversity experiment with 24 subtropical tree species to show that neighbourhood tree species richness generally promotes individual tree productivity. We found that the underlying mechanisms depend on a focal tree's functional traits: For species with a conservative resource-use strategy diversity effects were brought about by facilitation, and for species with acquisitive traits by competitive reduction. Moreover, positive diversity effects were strongest under low competition intensity (quantified as the total basal area of neighbours) for acquisitive species, and under high competition intensity for conservative species. Our findings demonstrate that net biodiversity effects in tree communities can vary over small spatial scales, emphasising the need to consider variation in local neighbourhood interactions to better understand effects at the community level.
对树木群落的研究表明，物种多样性能够提高森林生产力，但在局部邻域水平上的驱动机制仍知之甚少。在此，我们利用来自一个包含24种亚热带树种的大规模生物多样性实验的数据，表明邻域树种丰富度通常会促进单株树木的生产力。我们发现，潜在机制取决于目标树的功能性状：对于具有保守资源利用策略的物种，多样性效应是由促进作用产生的，而对于具有获取性性状的物种，则是由竞争减少产生的。此外，对于具有获取性性状的物种，正多样性效应在低竞争强度（以邻树总断面积量化）下最强，而对于保守物种，则在高竞争强度下最强。我们的研究结果表明，树木群落中的净生物多样性效应在小空间尺度上会有所不同，强调需要考虑局部邻域相互作用的变化，以便更好地理解群落水平上的效应。
