Avoiding the last supper: parentage analysis indicates multi-generational survival of re-introduced ‘toad-smart’ lineage
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Invasive species are a leading cause of animal extinctions. It is difficult to eradicate established and widespread populations of invaders, so we need novel approaches to reduce their impact on imperilled wildlife. In Australia, the toxic cane toad Rhinella marina has caused local extinctions of northern quolls Dasyurus hallucatus. Quolls lack immunity to toad toxins, and die after attacking adult toads. Using a novel approach, we modified quoll behaviour by feeding them small, non-lethal toads laced with a nausea-inducing chemical. Quolls that consumed the baits became ill, and subsequently ignored toads. We reintroduced these ‘toad-smart’ quolls to Kakadu National Park to determine whether aversion training could be an effective conservation tool. To measure the success of our innovation, it was important that reintroduced quolls survived to reproduce in a toad-infested landscape. We used parentage analysis to confirm the maternity of 12 wild-born quolls. ‘Toad-smart’ female quolls not only survived to reproduce, but their children and grandchildren survived as well. Training a single cohort of quolls yielded a long-term conservation benefit, without requiring continued conservation effort or eradication of the toxic invader.
KeywordsMaternity Conditioned taste aversion Reintroduction Marsupial Invasive
We thank Damien Stanioch, Lynda Veyret, Dion Wedd, and the Territory Wildlife Park staff for raising quolls, training, and assistance in the field. We thank Stephanie O’Donnell for assisting with quoll training and the reintroduction to the field site. We particularly thank the Traditional Owners for supporting the project and allowing us to work in the East Alligator region. We are indebted to the Kakadu Rangers, trainees, and all the volunteers, especially Libby Dwyer, Belinda McCarthy, Sandra Riemer, and Tim Dempster, who provided assistance in the field. We thank Steve Winderlich, Anne O’Dea, Greg Sattler, Matthew Dunn, and Patrick Shaughnessy for advice and logistical support. We would also like to acknowledge the technical assistance of Mia Hillyer and the WA Department of Parks and Wildlife for processing of DNA samples. Financial assistance was kindly provided by the Federal Government’s Caring for Our Country grant scheme, the Australian Research Council, the Mazda Foundation, and the National Geographic Conservation Trust. We thank two anonymous reviewers for their constructive feedback on an earlier draft of the manuscript, and the Flora and Fauna Division of the NT Department of Environment and Natural Resources for allowing us to use the image of the northern quoll.
Compliance with Ethical Standards
The study was conducted within Kakadu National Park in accordance with The Australian Code of Practice for the Care and Use of Animals for Scientific Purposes (1997). The area is jointly managed by traditional land-owners and the Australian federal government. Permission to undertake the study was obtained through Kakadu National Park (Permit Number: RK844). The research was approved by the University of Sydney Animal Ethics Committee (Protocol L04/7-2008/3/4823) and the University of Technology Sydney Animal Care and Ethics Committee (Protocol 2012-082A).
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