Dominant carnivore loss benefits native avian and invasive mammalian scavengers

Scavenging by large carnivores is integral for ecosystem functioning by limiting the build-up of carrion and facilitating widespread energy flows. However, top carnivores have declined across the world, triggering trophic shifts within ecosystems. In this study, we use a natural ‘removal experiment’ of disease-driven decline and island extirpation of native mammalian (marsupial) carnivores to investigate top-down control on utilisation of experimentally placed carcasses by two mesoscavengers – the invasive feral cat and native forest raven. Ravens were the main beneficiary of carnivore loss, scavenging for five times longer in the absence of native mammalian carnivores. Cats scavenged on half of all carcasses in the region without dominant native carnivores. This was eight times more than in areas where other carnivores were at high densities. All carcasses persisted longer than the three-week monitoring period in the absence of native mammalian carnivores, while in areas with high carn...

大型食肉动物的食腐行为通过限制腐肉堆积、促进全域能量流动，是生态系统功能正常运转不可或缺的核心环节。然而，全球范围内的顶级食肉动物种群普遍出现衰减，引发了生态系统内部的营养级动态变化。本研究依托一场由疾病驱动的本土哺乳类（有袋类）食肉动物种群下降与岛屿局部灭绝的天然"清除实验"，探究下行调控（top-down control）对两种中型食腐动物——入侵野猫与本土林鸦——利用人工布设的实验动物尸体的影响。研究结果显示，林鸦是本土哺乳类食肉动物消失后的主要受益类群：在无本土哺乳类食肉动物的区域，其食腐时长增至五倍。在无优势本土食肉动物的区域，半数实验布设的动物尸体被野猫啃食，这一比例较本土食肉动物高密度区域高出八倍。在无本土哺乳类食肉动物的区域，所有实验尸体的留存时长均超过三周的监测周期，而在食肉动物高密度区域……