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

• Main Authors: Allen, Benjamin L., Allen, Lee R., Engeman, Richard M., Leung, Luke K.-P.
• Format: Text
• Language: unknown
• Published: DigitalCommons@University of Nebraska - Lincoln 2014
• Subjects: Canis lupus dingo; Carnivore conservation; Fauna recovery planning; Ground-dwelling birds; Kangaroo; Poison baiting; Small mammals; Threatened species; Life Sciences; Canis lupus
• Online Access: https://digitalcommons.unl.edu/icwdm_usdanwrc/1441; https://digitalcommons.unl.edu/context/icwdm_usdanwrc/article/2438/viewcontent/Allen_FZ_2014_Sympatric_prey_responses.pdf

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 ...