Emergent Allee effects in top predators feeding on structured prey populations
Emergent Allee effects in top predators feeding on structured prey populations
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DOI：
10.1098/rspb.2002.2286
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发表时间：
2003-03-22
影响因子：
4.7
通讯作者：
Thieme, HR
中科院分区：
文献类型：
--
作者：
de Roos, AM;Persson, L;Thieme, HR
顶级捕食者，饲料在一个纯粹的剥削方式对较小的阶段的大小结构的猎物人口已被证明表现出阿利效应。这种Allee效应出现的变化，捕食者诱导的猎物种群的大小分布，并代表了捕食者的密度对自己的性能的反馈，其中反馈操作通过和被修改的猎物的生活史。我们证明，这些紧急Allee效应将发生只有当猎物，在没有捕食者，是通过其少年阶段之一，而不是通过成人生殖力的调节密度依赖性的发展。特别是，一个紧急的Allee效应发生，过度补偿是必需的成熟率的调节少年阶段，这样的少年密度的减少将增加总成熟率较大/较老的阶段。如果这个条件得到满足，捕食者与负尺寸选择，饲料上的小猎物，表现出紧急Allee效应，因为捕食者与正尺寸选择，饲料上的大型成年猎物。相比之下，捕食者饲料的青少年在调节阶段从来没有表现出紧急Allee效应。我们的结论是，许多物种的基本生活史特征，使他们容易表现出紧急Allee效应，从而增加了可能性，社区拥有替代稳定状态或表现出灾难性的结构和动态变化。
Top predators that forage in a purely exploitative manner on smaller stages of a size-structured prey population have been shown to exhibit an Allee effect. This Allee effect emerges from the changes that predators induce in the prey-population size distribution and represents a feedback of predator density on its own performance, in which the feedback operates through and is modified by the life history of the prey. We demonstrate that these emergent Allee effects will occur only if the prey, in the absence of predators, is regulated by density dependence in development through one of its juvenile stages, as opposed to regulation through adult fecundity. In particular, for an emergent Allee effect to occur, overcompensation is required in the maturation rate out of the regulating juvenile stage, such that a decrease in juvenile density will increase the total maturation rate to larger/older stages. If this condition is satisfied, predators with negative size selection, which forage on small prey, exhibit an emergent Allee effect, as do predators with positive size selection, which forage on large adult prey. By contrast, predators that forage on juveniles in the regulating stage never exhibit emergent Allee effects. We conclude that the basic life-history characteristics of many species make them prone to exhibiting emergent Allee effects, resulting in an increased likelihood that communities possess alternative stable states or exhibit catastrophic shifts in structure and dynamics.