title: Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages.
abstract: Disruption to species-interaction networks caused by irruptions of herbivores and mesopredators following extirpation of apex predators is a global driver of ecosystem reorganization and biodiversity loss. Most studies of apex predators' ecological roles focus on effects arising from their interactions with herbivores or mesopredators in isolation, but rarely consider how the effects of herbivores and mesopredators interact. Here, we provide evidence that multiple cascade pathways induced by lethal control of an apex predator, the dingo, drive unintended shifts in forest ecosystem structure. We compared mammal assemblages and understorey structure at seven sites in southern Australia. Each site comprised an area where dingoes were poisoned and an area without control. The effects of dingo control on mammals scaled with body size. Activity of herbivorous macropods, arboreal mammals and a mesopredator, the red fox, were greater, but understorey vegetation sparser and abundances of small mammals lower, where dingoes were controlled. Structural equation modelling suggested that both predation by foxes and depletion of understorey vegetation by macropods were related to small mammal decline at poisoned sites. Our study suggests that apex predators' suppressive effects on herbivores and mesopredators occur simultaneously and should be considered in tandem in order to appreciate the extent of apex predators' indirect effects.
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, , Locked Bag 1797, Penrith, New South Wales 2751, Australia, School of Biological Sciences, University of Sydney, , Sydney, New South Wales 2006, Australia, Centre for Ecosystem Science, University of New South Wales, , Sydney, New South Wales 2052, Australia, School of Biological, Earth and Environmental Sciences, University of New South Wales, , Sydney, New South Wales 2052, Australia.
authors.forename: N J
authors.initials: NJ
authors.lastname: Colman
authors.forename: C E
authors.initials: CE
authors.lastname: Gordon
authors.forename: M S
authors.initials: MS
authors.lastname: Crowther
authors.forename: M
authors.initials: M
authors.lastname: Letnic
mesh_terms: D000818:Animals; D001315:Australia; D044822:Biodiversity; D003247:Conservation of Natural Resources; D020387:Food Chain; D065928:Forests; D060434:Herbivory; D008322:Mammals; D011235:Predatory Behavior; D019596:Wolves
keywords: Canis dingo; apex predator; mesopredator release hypothesis; regime shift; trophic cascade