Sympatric prey responses to lethal top-predator control: predator manipulation experiments

Allen, Benjamin L. and Allen, Lee R. and Engeman, Richard M. and Leung, Luke K.-P. (2014) Sympatric prey responses to lethal top-predator control: predator manipulation experiments. Frontiers in Zoology, 11 (1). pp. 1-30. ISSN 1742-9994

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Abstract

Introduction: Many prey species around the world are suffering declines due to a variety of interacting causes such as land use change, climate change, invasive species and novel disease. Recent studies on the ecological roles of top-predators have suggested that lethal top-predator control by humans (typically undertaken to protect livestock or managed game from predation) is an indirect additional cause of prey declines through trophic cascade effects. Such studies have prompted calls to prohibit lethal top-predator control with the expectation that doing so will result in widespread benefits for biodiversity at all trophic levels. However, applied experiments investigating in situ responses of prey populations to contemporary top-predator management practices are few and none have previously been conducted on the eclectic suite of native and exotic mammalian, reptilian, avian and amphibian predator and prey taxa we simultaneously assess. We conducted a series of landscape-scale, multi-year, manipulative experiments at nine sites spanning five ecosystem types across the Australian continental rangelands to investigate the responses of sympatric prey populations to contemporary poison-baiting programs intended to control top-predators (dingoes) for livestock protection.
Results: Prey populations were almost always in similar or greater abundances in baited areas. Short-term prey responses to baiting were seldom apparent. Longer-term prey population trends fluctuated independently of baiting for every prey species at all sites, and divergence or convergence of prey population trends occurred rarely. Top-predator population trends fluctuated independently of baiting in all cases, and never did diverge or converge. Mesopredator population trends likewise fluctuated independently of baiting in almost all cases, but did diverge or converge in a few instances.
Conclusions: These results demonstrate that Australian populations of prey fauna at lower trophic levels are typically unaffected by top-predator control because top-predator populations are not substantially affected by contemporary control practices, thus averting a trophic cascade. We conclude that alteration of current top-predator management practices is probably unnecessary for enhancing fauna recovery in the Australian rangelands. More generally, our results suggest that theoretical and observational studies advancing the idea that lethal control of top-predators induces trophic cascades may not be as universal as previously supposed.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Open Access. Published version made available in accordance with Creative Commons Attribution License 4.0.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 30 Jun 2016 06:17
Last Modified: 22 Mar 2017 06:24
Uncontrolled Keywords: Canis lupus dingo; carnivore conservation; fauna recovery planning; ground-dwelling birds; kangaroo; poison baiting; small mammals; threatened species
Fields of Research : 05 Environmental Sciences > 0502 Environmental Science and Management > 050211 Wildlife and Habitat Management
Identification Number or DOI: 10.1186/s12983-014-0056-y
URI: http://eprints.usq.edu.au/id/eprint/29417

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