Data from: Incorporating disturbance into trophic ecology: fire history shapes mesopredator suppression by an apex predator

1.Apex predators can suppress smaller bodied ‘mesopredators’. In doing so, they can provide refuge to species preyed upon by mesopredators, which is particularly important in regions where mesopredators are invasive. While most studies of mesopredator suppression focus on the response of mesopredators to human control of apex predators, other factors –including natural and anthropogenic disturbance – also drive the occurrence of apex predators and, in doing so, might shape spatial patterns of mesopredator suppression. 2.We examined the role of fire in shaping the occurrence of an apex predator and, by extension, mesopredators and small mammals in a fire-prone region of semi-arid Australia. We measured the activity of an apex predator (the dingo, Canis dingo); an invasive mesopredator it is known to suppress, the red fox (Vuples vuples); and two species of native small mammal (Mitchell's hopping mouse, Notomys mitchelli; silky mouse, Pseudomys apodemoides) that are potential prey, across 21 fire mosaics (each 12.56 km2). We used piecewise structural equation modelling and scenario analysis to explore the interactions between fire, predators and prey. 3.We found that dingoes were affected by fire history at the landscape scale, showing a preference for recently burned areas. While foxes were not directly affected by fire history, a negative association between dingoes and foxes meant that fire had an indirect impact on foxes, mediated through dingoes. Despite the suppression of foxes by dingoes, we did not observe a trophic cascade as small mammals were not negatively associated with foxes or positively associated with dingoes. 4.Synthesis and applications. Disturbance regimes have the capacity to shape patterns of mesopredator suppression when they alter the distributions of apex predators. Environmental change that promotes native predators can therefore help suppress mesopredators – a common conservation objective in regions with invasive mesopredators. The indirect consequences of disturbance regimes should be considered when managing disturbance (e.g. fire) for biodiversity conservation.

1. 顶级捕食者(Apex predators)可抑制体型较小的中型捕食者(mesopredators)。通过该调控作用，它们能够为被中型捕食者捕食的物种提供生存庇护，这在中型捕食者为入侵物种的区域尤为关键。现有关于中型捕食者抑制效应的研究，多聚焦于中型捕食者对人类管控顶级捕食者的响应，而其他因素——包括自然干扰与人为干扰——同样会驱动顶级捕食者的分布，并借此塑造中型捕食者抑制的空间格局。
2. 本研究在澳大利亚半干旱易火区域，探究了火对顶级捕食者分布的调控作用，及其进而对中型捕食者与小型哺乳动物的影响。我们在21个火烧镶嵌斑块（单个斑块面积为12.56 km²）中，监测了三类生物的活动：1种顶级捕食者——澳洲野犬(Canis dingo)；1种已知可被其抑制的入侵中型捕食者——赤狐(Vulpes vulpes，原文笔误为Vuples vuples)；以及2种作为潜在猎物的本土小型哺乳动物：米切尔跳鼠(Notomys mitchelli)与丝毛鼠(Pseudomys apodemoides)。本研究采用分段结构方程模型(piecewise structural equation modelling)与情景分析(scenario analysis)，探究火、捕食者与猎物间的相互作用关系。
3. 研究结果表明，澳洲野犬的分布受景观尺度火烧历史的调控，偏好近期过火区域。尽管赤狐并未直接受火烧历史的影响，但澳洲野犬与赤狐间存在显著负相关关系，意味着火可通过介导澳洲野犬的分布，对赤狐产生间接调控效应。尽管澳洲野犬可抑制赤狐种群，但本研究并未观测到营养级联效应(trophic cascade)：小型哺乳动物与赤狐间未呈现负相关，与澳洲野犬间也未呈现正相关。
4. 综合与应用。当干扰制度改变顶级捕食者的分布格局时，其可塑造中型捕食者抑制的空间模式。因此，能够促进本土捕食者的环境变化，可助力抑制中型捕食者——这是存在入侵中型捕食者区域的常见生物保育目标。在为生物多样性保育开展干扰（如火）管理时，应充分考量干扰制度的间接生态效应。