Reintroducing native predators improves antipredator responses in naïve prey

Prey animals may lack appropriate predator avoidance behaviours to novel predators, which has contributed to the decline of many species worldwide following human introduction of novel predators. Excluding novel predators from conservation reserves has been used to attempt to recover naïve species with mixed success. However, in the absence of predators, prey naiveté can be exacerbated. Reintroducing native predators has been suggested as a solution to addressing this problem and may act as a stepping stone to improve behavioural responses to novel predators. We tested the behavioural responses of two prey species, the burrowing bettong, Bettongia lesueur, and spinifex hopping mouse, Notomys alexis, to the reintroduction of a native predator, the western quoll, Dasyurus geoffroii, and determined whether exposure to a native predator improved their antipredator responses to introduced feral cats, Felis catus. Quoll-exposed bettongs spent less time engaged in inattentive foraging behaviours compared to control (nonpredator exposed) bettongs but did not discriminate between predator and nonpredator visual or olfactory cues (native or novel). Quoll-exposed spinifex hopping mice modified their foraging in open habitats and increased wariness in the presence of quoll stimuli, whereas cat-exposed hopping mice only exhibited increased wariness in the presence of cat stimuli. Our results show that reintroductions of native predators improved general antipredator responses in native prey species, but there was only weak evidence that this led to an improved response to introduced predators. However, reintroducing native predators improved general antipredator behaviour in ontogenetically naïve populations which may make them more suitable for releases outside conservation fences where novel predators are present.