Temporal partitioning of activity: rising and falling top-predator abundance triggers community-wide shifts in diel activity
Temporal partitioning of activity: rising and falling top-predator abundance triggers community-wide shifts in diel activity
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DOI：
10.1111/ecog.04485
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发表时间：
2019-09-27
期刊：
影响因子：
5.9
通讯作者：
Jones, Menna E.
中科院分区：
文献类型：
--
作者：
Cunningham, Calum X.;Scoleri, Vince;Jones, Menna E.
顶端捕食者引起竞争者和猎物的回避行为，这可能导致生态位划分，促进共存。我们调查的时间生态位在哺乳动物群落中的分区的变化，响应于两个并行的自然实验：1）塔斯马尼亚魔鬼的严重下降，由于传染性癌症，和2）塔斯马尼亚魔鬼的引入到一个岛屿，随后的人口增加，在丰度的快速下降和快速增加。我们专注于魔鬼，两个中型捕食者和三个猎物物种，使我们能够研究生态位划分的背景下，种内和种间的竞争，捕食者-猎物的相互作用。最一致的时间活动发生在魔鬼本身，这是活跃在晚上早些时候在高密度，大概是因为种内竞争加剧。当魔鬼很少时，它们最接近的竞争对手，斑尾袋鼬，在夜晚的早期增加了活动，导致与魔鬼的时间生态位重叠增加，并建议从干扰竞争中释放出来。入侵野猫，另一种中捕食者，没有改变其时间活动的反应，无论是减少或增加魔鬼密度。时间活动的主要猎物种类的魔鬼的变化是强大的，在响应上升比下降魔鬼密度。我们推断，当捕食者密度上升时，与不避免捕食者相关的成本（即死亡）高于随着捕食者密度下降而继续采取回避行为的成本（即觅食机会的损失），因此捕食者密度上升可能会引发更快的转变。魔鬼丰度的快速变化提供了一个独特的框架来测试顶级捕食者的非致命性影响如何影响整个社区的时间生态位的划分，揭示了这种顶级捕食者对其他物种的昼夜活动有着重要但不同的影响。
Top predators cause avoidance behaviours in competitors and prey, which can lead to niche partitioning and facilitate coexistence. We investigate changes in partitioning of the temporal niche in a mammalian community in response to both the rapid decline in abundance of a top predator and its rapid increase, produced by two concurrent natural experiments: 1) the severe decline of the Tasmanian devil due to a transmissible cancer, and 2) the introduction of Tasmanian devils to an island, with subsequent population increase. We focus on devils, two mesopredators and three prey species, allowing us to examine niche partitioning in the context of intra- and inter-specific competition, and predator-prey interactions. The most consistent shift in temporal activity occurred in devils themselves, which were active earlier in the night at high densities, presumably because of heightened intraspecific competition. When devils were rare, their closest competitor, the spotted-tailed quoll, increased activity in the early part of the night, resulting in increased overlap with the devil's temporal niche and suggesting release from interference competition. The invasive feral cat, another mesopredator, did not shift its temporal activity in response to either decreasing or increasing devil densities. Shifts in temporal activity of the major prey species of devils were stronger in response to rising than to falling devil densities. We infer that the costs associated with not avoiding predators when their density is rising (i.e. death) are higher than the costs of continuing to adopt avoidance behaviours as predator densities fall (i.e. loss of foraging opportunity), so rising predator densities may trigger more rapid shifts. The rapid changes in devil abundance provide a unique framework to test how the non-lethal effects of top predators affect community-wide partitioning of temporal niches, revealing that this top predator has an important but varied influence on the diel activity of other species.