Smith Justine A, Suraci Justin P, Clinchy Michael, Crawford Ayana, Roberts Devin, Zanette Liana Y, Wilmers Christopher C
Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA.
Proc Biol Sci. 2017 Jun 28;284(1857). doi: 10.1098/rspb.2017.0433.
Large carnivores' fear of the human 'super predator' has the potential to alter their feeding behaviour and result in human-induced trophic cascades. However, it has yet to be experimentally tested if large carnivores perceive humans as predators and react strongly enough to have cascading effects on their prey. We conducted a predator playback experiment exposing pumas to predator (human) and non-predator control (frog) sounds at puma feeding sites to measure immediate fear responses to humans and the subsequent impacts on feeding. We found that pumas fled more frequently, took longer to return, and reduced their overall feeding time by more than half in response to hearing the human 'super predator'. Combined with our previous work showing higher kill rates of deer in more urbanized landscapes, this study reveals that fear is the mechanism driving an ecological cascade from humans to increased puma predation on deer. By demonstrating that the fear of humans can cause a strong reduction in feeding by pumas, our results support that non-consumptive forms of human disturbance may alter the ecological role of large carnivores.
大型食肉动物对人类“超级捕食者”的恐惧有可能改变它们的进食行为,并导致人为引发的营养级联效应。然而,大型食肉动物是否将人类视为捕食者并做出足够强烈的反应,从而对其猎物产生级联效应,这一点尚未经过实验验证。我们进行了一项捕食者回放实验,在美洲狮的觅食地点让它们接触捕食者(人类)和非捕食者对照(青蛙)的声音,以测量它们对人类的即时恐惧反应以及随后对进食的影响。我们发现,听到人类“超级捕食者”的声音后,美洲狮更频繁地逃离,返回所需时间更长,并且它们的总体进食时间减少了一半以上。结合我们之前的研究结果,即在城市化程度更高的地区鹿的死亡率更高,这项研究表明,恐惧是驱动从人类到美洲狮对鹿捕食增加的生态级联效应的机制。通过证明对人类的恐惧会导致美洲狮的进食大幅减少,我们的研究结果支持了这样一种观点,即非消耗性的人类干扰形式可能会改变大型食肉动物的生态作用。