Área de Biodiversidad y Conservación, Department of Biology, Geology, Physics and Inorganic Chemistry, Universidad Rey Juan Carlos, Madrid, Spain.
Centro de Investigaciones sobre Desertificación CIDE, CSIC-UVEG-GV, Carretera de Moncada a Náquera, Moncada, Spain.
J Anim Ecol. 2022 May;91(5):1024-1035. doi: 10.1111/1365-2656.13682. Epub 2022 Mar 23.
Apex predators play key roles in food webs and their recovery can trigger trophic cascades in some ecosystems. Intra-guild competition can reduce the abundances of smaller predators and perceived predation risk can alter their foraging behaviour thereby limiting seed dispersal by frugivorous carnivores. However, little is known about how plant-frugivore mutualisms could be disturbed in the presence of larger predators. We evaluated the top-down effect of the regional superpredator, the Iberian lynx Lynx pardinus, on the number of visits and fruits consumed by medium-sized frugivorous carnivores, as well as the foraging behaviour of identified individuals, by examining the consumption likelihood and the foraging time. We carried out a field experiment in which we placed Iberian pear Pyrus bourgaeana fruits beneath fruiting trees and monitored pear removal by frugivorous carnivores, both inside and outside lynx ranges. Using camera traps, we recorded the presence of the red fox Vulpes vulpes, the Eurasian badger Meles meles and the stone marten Martes foina, as well as the number of fruits they consumed and their time spent foraging. Red fox was the most frequent fruit consumer carnivore. We found there were fewer visits and less fruit consumed by foxes inside lynx ranges, but lynx presence did not seem to affect badgers. We did not observe any stone marten visits inside lynx territories. The foraging behaviour of red foxes was also altered inside lynx ranges whereby foxes were less efficient, consuming less fruit per unit of time and having shorter visits. Local availability of fruit resources, forest coverage and individual personality also were important variables to understand visitation and foraging in a landscape of fear. Our results show a potential trophic cascade from apex predators to primary producers. The presence of lynx can reduce frugivorous carnivore numbers and induce shifts in their feeding behaviour that may modify the seed dispersal patterns with likely consequences for the demography of many fleshy-fruited plant species. We conclude that knowledge of the ecological interactions making up trophic webs is an asset to design effective conservation strategies, particularly in rewilding programs.
顶级捕食者在食物网中发挥着关键作用，它们的恢复可以在一些生态系统中引发营养级联。种内竞争会降低较小捕食者的数量，而感知到的捕食风险会改变它们的觅食行为，从而限制食果性肉食动物传播种子。然而，对于在更大的捕食者存在的情况下植物-食果动物共生关系如何受到干扰，我们知之甚少。我们评估了区域超级捕食者——伊比利亚猞猁 Lynx pardinus——对中型食果肉食动物访问次数和消耗果实数量的自上而下的影响，以及通过检查消费可能性和觅食时间来确定个体的觅食行为。我们在一个野外实验中进行了研究，在那里我们将梨 Pyrus bourgaeana 果实放在结果树下，并监测食果肉食动物在猞猁活动范围内外对果实的移除情况。我们使用相机陷阱记录了红狐 Vulpes vulpes、欧亚獾 Meles meles 和石貂 Martes foina 的存在情况，以及它们消耗的果实数量和觅食时间。红狐是最常见的果实消费者肉食动物。我们发现，在猞猁活动范围内，狐狸的访问次数和消耗的果实数量减少，但猞猁的存在似乎不会影响獾。我们没有观察到石貂在猞猁领地内的访问。红狐的觅食行为也在猞猁活动范围内发生了变化，狐狸的效率降低，单位时间内消耗的果实减少，访问时间缩短。了解恐惧景观中的访问和觅食情况的重要变量还包括当地果实资源的可用性、森林覆盖率和个体个性。我们的研究结果表明，顶级捕食者对初级生产者可能存在潜在的营养级联。猞猁的存在可能会降低食果肉食动物的数量，并诱导它们的觅食行为发生变化，这可能会改变种子传播模式，对许多肉质果实植物的种群动态产生可能的影响。我们得出结论，了解构成食物网的生态相互作用是制定有效保护策略的一项资产，特别是在重新引入野生生物的计划中。
