arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1908.07960q-bio.PE
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生态选择对物种多样性〈动〉<动>和特征分布的影响:预测和经验检验

The effects of ecological selection on species diversity and trait distribution: predictions and an empirical test

DeMalach Niv, Po-Ju Ke, Tadashi Fukami

摘要:

生态选择是群落聚集的主要驱动力。当具有中间性状值的物种获得最高的繁殖成功时,选择被归类为稳定,而当具有极端性状值的物种的适合度最高时,选择被认为是定向的。以往的研究探讨了不同选择类型对性状分布的影响,但选择对物种多样性〈动〉性<动>的影响仍不清楚。在这里,我们提出了一个框架来推断的类型和强度的选择,通过研究物种多样性〈动〉性<动>和性状分布一起对零期望。我们使用一个模拟模型来证实我们的预测,定向选择〈动〉应导致较低的物种多样性〈动〉<动>比稳定选择,尽管性状的社区加权方差有类似的效果。我们应用的框架,一年生植物的中围生态系统,以测试是否在物种多样性〈动〉性<动>两个栖息地之间的生产力不同的种子质量的选择差异。我们发现,在这两个栖息地,物种多样性〈动〉<动>低于零期望值,但物种多样性〈动〉性<动>更低的生产性栖息地。我们将这种差异归因于强定向选择〈动〉<动>的大种子物种在生产栖息地所示的性状社区加权平均值较高,社区加权方差低于零预期。在生产力较低的栖息地,我们发现,社区加权方差高于预期的机会,这表明种子质量可能是在这种条件下的生态位划分的驱动程序。总之,我们的研究结果表明,将物种多样性〈动〉<动>和性状分布视为由同一过程(生态选择)驱动的相互关联的模式,有助于理解群落组装。

英文摘要:

Ecological selection is a major driver of community assembly. Selection is classified as stabilizing when species with intermediate trait values gain the highest reproductive success, whereas selection is considered directional when fitness is highest for species with extreme trait values. Previous studies have investigated the effects of different selection types on trait distribution, but the effects of selection on species diversity have remained unclear. Here, we propose a framework for inferring the type and strength of selection by studying species diversity and trait distribution together against null expectations. We use a simulation model to confirm our prediction that directional selection should lead to lower species diversity than stabilizing selection despite a similar effect on trait community-weighted variance. We apply the framework to a mesocosm system of annual plants to test whether differences in species diversity between two habitats that vary in productivity are related to differences in selection on seed mass. We show that, in both habitats, species diversity was lower than the null expectation, but that species diversity was lower in the more productive habitat. We attribute this difference to strong directional selection for large-seeded species in the productive habitat as indicated by trait community-weighted-mean being higher and community-weighted variance being lower than the null expectations. In the less productive habitat, we found that community-weighted variance was higher than expected by chance, suggesting that seed mass could be a driver of niche partitioning under such conditions. Altogether, our results suggest that viewing species diversity and trait distribution as interrelated patterns driven by the same process, ecological selection, is helpful in understanding community assembly.

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