Abstract The conventional approach to conserving threatened biota is to identify drivers of decline, instigate actions to mitigate threatening processes, and monitor interventions to test their effectiveness and ensure target species recover. In Australia, predation by introduced predators is a threatening process for many native mammals. Here we report the results of a 15 year monitoring study in an iconic Australian reserve, Booderee National Park, where exotic Red Fox (Vulpes vulpes) populations have been controlled through an intensive poison baiting program since 2003. Unexpectedly, we documented the collapse of native mammal fauna during this period, including fully arboreal species that should be largely unaffected by fox predation – such as the nationally Vulnerable Greater Glider (Petauroides volans) and Common Ringtail Possum (Pseudocheirus peregrinus). We used path analysis to explore potential causes of these unexpected declines. We found no compelling evidence to support hypotheses that competition with increasing native species, native predator release, or increases in native herbivores underpinned mammal declines. Beyond the path analysis, data from other studies completed both inside Booderee National Park and outside (where intensive fox baiting does not occur yet depleted fauna species remain), allowed us to rule out several drivers of change. The temporal declines we documented for arboreal marsupials were not anticipated nor explained by any clear mechanism. We propose the use of experimentally-guided reintroductions and translocations to: (1) restore empty niches such as the currently vacant apex mammal predator niche, (2) reconstruct the now depleted arboreal marsupial guild, and (3) further test key hypotheses associated with mammal decline. We also suggest that given the potential for perverse outcomes following large-scale management interventions (even those where there is high confidence of success), wildlife managers should consider maintaining reference areas (where there is no management intervention). Finally, as the declines we documented were unexpected and rapid, there is a clear need to develop more sensitive early warning signals to alert conservation managers to impending problems, allowing them to alter management regimes before major declines occur.

中文翻译：

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保护难题和应对多种物种不明原因减少的挑战

摘要 保护受威胁生物群的传统方法是确定衰退的驱动因素，采取行动减轻威胁过程，并监测干预措施以测试其有效性并确保目标物种恢复。在澳大利亚，外来掠食者的捕食对许多本地哺乳动物来说是一个威胁过程。在这里，我们报告了在澳大利亚标志性保护区 Booderee 国家公园进行的 15 年监测研究的结果，自 2003 年以来，外来红狐（Vulpes vulpes）种群已通过密集毒饵计划得到控制。这一时期的哺乳动物群，包括完全不会受到狐狸捕食影响的完全树栖物种——例如全国性易危大滑翔机（Petauroides volans）和普通环尾负鼠（Pseudocheirus peregrinus）。我们使用路径分析来探索这些意外下降的潜在原因。我们没有发现令人信服的证据来支持与增加的本地物种、本地捕食者的释放或本地食草动物的增加的竞争导致哺乳动物下降的假设。除了路径分析之外，来自 Booderee 国家公园内外的其他研究的数据（在那里没有发生密集的狐狸诱饵，但仍然存在枯竭的动物群），这使我们能够排除几个变化的驱动因素。我们记录的树栖有袋动物的时间下降没有预料到，也没有任何明确的机制解释。我们建议使用实验指导的重新引入和易位：（1）恢复空的生态位，例如当前空置的顶端哺乳动物捕食者生态位，（2）重建现已枯竭的树栖有袋动物行会，以及（3）进一步测试与相关的关键假设哺乳动物衰退。我们还建议，鉴于大规模管理干预（即使是那些成功的信心很高的干预）后可能出现不良结果，野生动物管理者应考虑维护参考区域（没有管理干预的地方）。最后，由于我们记录的下降是出乎意料和迅速的，因此显然需要开发更敏感的预警信号，以提醒保护管理者注意即将发生的问题，让他们能够在发生重大下降之前改变管理制度。