Fortunel Claire, Paine C E Timothy, Fine Paul V A, Mesones Italo, Goret Jean-Yves, Burban Benoit, Cazal Jocelyn, Baraloto Christopher
INRA, UMR Ecologie des Forêts de Guyane, BP 709, 97387, Kourou Cedex, France.
Department of Biology, University of Maryland, College Park, MD, 20742, USA.
Ecol Lett. 2016 Oct;19(10):1256-66. doi: 10.1111/ele.12661.
Understanding the mechanisms generating species distributions remains a challenge, especially in hyperdiverse tropical forests. We evaluated the role of rainfall variation, soil gradients and herbivory on seedling mortality, and how variation in seedling performance along these gradients contributes to habitat specialisation. In a 4-year experiment, replicated at the two extremes of the Amazon basin, we reciprocally transplanted 4638 tree seedlings of 41 habitat-specialist species from seven phylogenetic lineages among the three most important forest habitats of lowland Amazonia. Rainfall variation, flooding and soil gradients strongly influenced seedling mortality, whereas herbivory had negligible impact. Seedling mortality varied strongly among habitats, consistent with predictions for habitat specialists in most lineages. This suggests that seedling performance is a primary determinant of the habitat associations of adult trees across Amazonia. It further suggests that tree diversity, currently mostly harboured in terra firme forests, may be strongly impacted by the predicted climate changes in Amazonia.
理解物种分布形成的机制仍然是一项挑战，尤其是在生物多样性极高的热带森林中。我们评估了降雨变化、土壤梯度和食草作用对幼苗死亡率的影响，以及幼苗在这些梯度上的表现差异如何导致栖息地特化。在一项为期4年的实验中，我们在亚马逊盆地的两个极端地区进行了重复实验，将来自7个系统发育谱系的41种栖息地特化树种的4638株树苗在低地亚马逊地区三个最重要的森林栖息地之间进行了相互移栽。降雨变化、洪水和土壤梯度对幼苗死亡率有强烈影响，而食草作用的影响可以忽略不计。不同栖息地之间的幼苗死亡率差异很大，这与大多数谱系中栖息地特化树种的预测一致。这表明幼苗表现是亚马逊地区成年树木栖息地关联的主要决定因素。这进一步表明，目前大多存在于高地森林中的树木多样性可能会受到亚马逊地区预测的气候变化的强烈影响。
