Patch use in time and space for a meso-predator in a risky world
Patch use in time and space for a meso-predator in a risky world
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DOI：
10.1007/s00442-008-1243-3
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发表时间：
2009-03-01
期刊：
影响因子：
2.7
通讯作者：
Kotler, Burt P.
中科院分区：
文献类型：
--
作者：
Mukherjee, Shomen;Zelcer, Michal;Kotler, Burt P.
捕食者-被捕食者研究通常假设一个三营养级系统，在这个系统中，捕食者觅食没有任何捕食风险。由于中型掠食者本身也是潜在的猎物，它们也需要在食物和安全之间进行权衡。我们应用觅食理论研究补丁使用和栖息地选择的中型捕食者，赤狐。我们提出的证据表明，狐狸使用退出收获率规则时，决定是否放弃觅食补丁，经验收益递减时，从耗尽的食物补丁觅食。此外，我们的数据表明，红狐的补丁使用决策的影响，不仅由食物的可用性，但也由他们的感知捕食风险。狐狸的行为受到月光的影响，与月光下的夜晚相比，狐狸在黑暗的夜晚更彻底地消耗食物资源（较低的放弃密度）。狐狸在鬣狗活动较低的地方和时间更活跃，从而降低了鬣狗的风险。虽然鬣狗在月亮期间最不活跃，但在满月之夜最活跃，但狐狸的情况正好相反。狐狸在新月期间的活动是满月之夜的两倍，这表明捕食的成本不同。有趣的是，与没有其他捕食者（狼的粪便）的斑块相比，具有其他捕食者线索的斑块中的资源被消耗到显着较低的水平。我们的研究结果强调需要考虑捕食风险的中间捕食者，也表明如何补丁使用理论和实验食物补丁可以用于捕食者。总之，这些结果可能有助于我们更好地理解营养相互作用。
Predator-prey studies often assume a three trophic level system where predators forage free from any risk of predation. Since meso-predators themselves are also prospective prey, they too need to trade-off between food and safety. We applied foraging theory to study patch use and habitat selection by a meso-predator, the red fox. We present evidence that foxes use a quitting harvest rate rule when deciding whether or not to abandon a foraging patch, and experience diminishing returns when foraging from a depletable food patch. Furthermore, our data suggest that patch use decisions of red foxes are influenced not just by the availability of food, but also by their perceived risk of predation. Fox behavior was affected by moonlight, with foxes depleting food resources more thoroughly (lower giving-up density) on darker nights compared to moonlit nights. Foxes reduced risk from hyenas by being more active where and when hyena activity was low. While hyenas were least active during moon, and most active during full moon nights, the reverse was true for foxes. Foxes showed twice as much activity during new moon compared to full moon nights, suggesting different costs of predation. Interestingly, resources in patches with cues of another predator (scat of wolf) were depleted to significantly lower levels compared to patches without. Our results emphasize the need for considering risk of predation for intermediate predators, and also shows how patch use theory and experimental food patches can be used for a predator. Taken together, these results may help us better understand trophic interactions.