Feral individuals of the cat Felis catus are recognized internationally as a threat to biodiversity. Open, non-insular systems support a large proportion of the world’s biodiversity, but the population-level impacts of feral cats in these systems are rarely elucidated. This limits prioritization and assessment of the effectiveness of management interventions. We quantified the predatory impact of feral cats on small mammals in open, non-insular forest systems in Tasmania, Australia in the context of other factors hypothesized to affect small mammal densities and survival, namely the density of a native carnivore, co-occurring small mammals, and rainfall. Change in feral cat density was the most important determinant of small mammal density and survival. We calculated that, on average, a 50% reduction in feral cat density could result in 25% and 10% increases in the density of the swamp rat Rattus lutreolus and long-tailed mouse Pseudomys higginsi, respectively. Low-level culling of feral cats that we conducted on two of our four study sites to experimentally alter feral cat densities revealed that swamp rat survival was highest when feral cat densities were stable. We conclude that feral cats exert downward pressure on populations of indigenous small mammals in temperate forest systems. However, alleviating this downward pressure on prey by culling a large proportion of the feral cat population is difficult as current methods for reducing feral cat populations in cool temperate forest systems are ineffective, and potentially even counterproductive. We suggest using an adaptive approach that regularly and robustly monitors how feral cats and small mammals respond to management interventions that are intended to conserve vulnerable prey species.

中文翻译：

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最后方舟的攻略：野猫对塔斯马尼亚森林生态系统中小型哺乳动物的影响

猫Felis catus 的野生个体被国际公认为对生物多样性的威胁。开放的、非孤立的系统支持着世界上很大一部分生物多样性，但这些系统中野猫对种群水平的影响很少被阐明。这限制了对管理干预措施有效性的优先排序和评估。我们在假设影响小型哺乳动物密度和生存的其他因素的背景下，量化了野猫对澳大利亚塔斯马尼亚开放、非岛屿森林系统中的小型哺乳动物的掠食性影响，即本地食肉动物的密度，共同出现的小型哺乳动物和降雨。野猫密度的变化是小型哺乳动物密度和存活率的最重要决定因素。我们计算得出，平均而言，褐家鼠和长尾鼠Pseudomys higginsi， 分别。我们在四个研究地点中的两个地点对野猫进行了低水平的扑杀，以通过实验改变野猫的密度，结果表明，当野猫密度稳定时，沼泽鼠的存活率最高。我们得出的结论是，野猫对温带森林系统中的本土小型哺乳动物种群施加了下行压力。然而，通过扑杀大部分野猫种群来减轻对猎物的这种向下压力是困难的，因为目前在冷温带森林系统中减少野猫种群的方法是无效的，甚至可能适得其反。我们建议使用一种适应性方法，定期和稳健地监测野猫和小型哺乳动物对旨在保护脆弱猎物物种的管理干预措施的反应。