Alien predators are more dangerous than native predators to prey populations

• Published in: Proceedings of the Royal Society. B, Biological sciences Biological sciences, 2007-05, Vol.274 (1615), p.1237-1243
• Main Authors: Salo, Pälvi, Korpimäki, Erkki, Banks, Peter B, Nordström, Mikael, Dickman, Chris R
• Format: Article
• Language: English
• Subjects: Animals; Biodiversity; Biodiversity Conservation; Birds - growth & development; Birds of prey; Conservation of Natural Resources; Ecosystem; Filter Effect; Invasive Species; Mammals; Mammals - growth & development; Materials; Population Dynamics; Population ecology; Population size; Predation Impact; Predators; Predatory Behavior; Prey Naiveté; Review; Species extinction; Vertebrates
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.2006.0444

Alien predators are widely considered to be more harmful to prey populations than native predators. To evaluate this expectation, we conducted a meta-analysis of the responses of vertebrate prey in 45 replicated and 35 unreplicated field experiments in which the population densities of mammalian and avian predators had been manipulated. Our results showed that predator origin (native versus alien) had a highly significant effect on prey responses, with alien predators having an impact double that of native predators. Also the interaction between location (mainland versus island) and predator origin was significant, revealing the strongest effects with alien predators in mainland areas. Although both these results were mainly influenced by the huge impact of alien predators on the Australian mainland compared with their impact elsewhere, the results demonstrate that introduced predators can impose more intense suppression on remnant populations of native species and hold them further from their predator-free densities than do native predators preying upon coexisting prey.