Data from: Housework or vigilance? Bilbies alter burrowing activity under threat of predation by feral cats

Behavioral adjustments to predation risk not only impose costs on prey species themselves but can also have cascading impacts on whole ecosystems. The greater bilby (Macrotis lagotis) is an important ecosystem engineer, modifying the physical environment through their digging activity, and supporting a diverse range of sympatric species that use its burrows for refuge and food resources. The bilby has experienced severe decline over the last 200 years, and the species is now restricted to approximately 20% of its former distribution. Introduced predators, such as the feral cat (Felis catus), have contributed to this decline. We used camera traps to monitor bilby burrows at four sites in Western Australia, where bilbies were exposed to varying levels of cat predation threat. We investigated the impact of feral cats on bilby behavior at burrows, particularly during highly vulnerable periods when they dig and clear away soil or debris from the burrow entrance as they perform burrow maintenance. There was little evidence that bilbies avoided burrows that were visited by a feral cat; however, bilbies reduced the time spent performing burrow maintenance in the days following a cat visit (p=0.010). We found the risk posed to bilbies varied over time, with twice the cat activity around full moon compared with dark nights. Bilby burrows are such valuable resources for ecosystem functioning that bilby predation by feral cats, as well as even indirect impacts on bilby behavioral responses to perceived predation risk, together may have a substantial ecosystem impact.

针对捕食风险的行为调整不仅会给猎物物种带来直接代价，还会对整个生态系统产生级联效应。兔耳袋狸（greater bilby，Macrotis lagotis）是一类关键的生态系统工程师，它们通过挖掘活动改造栖息地物理环境，并为诸多依赖其洞穴作为庇护与觅食资源的同域物种提供生存支持。在过去200年间，兔耳袋狸种群经历了严重衰退，目前其分布范围仅余原分布区的约20%。外来捕食者，例如野猫（feral cat，Felis catus），是导致该物种衰退的重要因素之一。本研究利用相机陷阱（camera traps）对西澳大利亚州四个样地的兔耳袋狸洞穴开展监测，这些样地内的兔耳袋狸面临不同强度的野猫捕食威胁。我们探究了野猫对兔耳袋狸在洞穴周边行为的影响，尤其是在其进行洞穴维护、挖掘并清理洞穴入口处土壤或碎屑的高度脆弱时段。研究结果显示，几乎无证据表明兔耳袋狸会避开曾有野猫到访的洞穴；但在野猫到访后的数日内，兔耳袋狸用于洞穴维护的时长显著减少（p=0.010）。此外，我们发现兔耳袋狸面临的捕食风险随时间波动：满月时段的野猫活动频率是暗夜时段的两倍。兔耳袋狸洞穴对生态系统功能具有极高价值，因此野猫对兔耳袋狸的直接捕食，以及间接影响兔耳袋狸对感知捕食风险的行为响应，二者的共同作用可能会对生态系统产生显著影响。