Plant pathogens drive density-dependent seedling mortality in a tropical tree
Plant pathogens drive density-dependent seedling mortality in a tropical tree
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DOI：
10.1111/j.1461-0248.2006.00905.x
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发表时间：
2006-05-01
期刊：
影响因子：
8.8
通讯作者：
Lewis, OT
中科院分区：
文献类型：
--
作者：
Bell, T;Freckleton, RP;Lewis, OT
对热带森林树木异常多样性的一种解释是，草食动物或病原体导致的密度依赖性死亡使当地稀有物种处于优势地位。依赖密度的种子和小苗死亡在热带森林中尤其严重，但其原因仍不确定。在这里，我们的实验表明，来自Omycota的病原体与新热带树木Sebastiana Longicuspis幼苗的严重死亡有关。与使用杀菌剂处理的地块相比，未处理地块的幼苗死亡率高出8倍。死亡率强烈依赖于密度：在使用杀菌剂的地块中，存活率不受密度的影响，但在低密度下，未喷洒的地块的存活率高出三倍以上。在一项同步的非操纵性研究中观察到的密度依赖性死亡率是高度瞬时的，这表明短期观察性研究可能低估了病原体诱导的死亡的强度和形式。如果这种影响广泛存在，植物病原体可能在维持和构建热带多样性方面发挥关键作用。
One explanation for the extraordinary diversity of tropical forest trees is that density-dependent mortality from herbivores or pathogens puts locally rare species at an advantage. Density-dependent mortality of seeds and small seedlings is particularly intense in tropical forests, but its causes remain uncertain. Here, we show experimentally that pathogens from the Oomycota are associated with intense mortality in seedlings of a neotropical tree, Sebastiana longicuspis. Seedlings in untreated plots experienced eight times higher mortality compared with seedlings in plots treated with fungicide. Mortality was strongly density dependent: in fungicide-treated plots survival was unaffected by density, but survival in unsprayed plots was over three times higher at low density. Density-dependent mortality observed in a simultaneous, non-manipulative study was highly transient, suggesting that short-term observational studies may underestimate the intensity and form of pathogen-induced mortality. If such effects are widespread, plant pathogens may play a key role in maintaining and structuring tropical diversity.