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Use of rodenticides is a common method for eradication of invasive rodents from islands, with eradication projects increasingly being undertaken on inhabited islands or islands used by people for harvesting food. The expansion of eradication projects to inhabited islands will require that all real and perceived human health risks from the projects are socially acceptable, or effectively mitigated. When broad-scale use of rodenticide for eradication is proposed on inhabited islands, it is usual for concerns to be raised about the risks of rodenticide exposure to people, livestock, pets, game animals, and marine food sources. Although risks to humans have been assessed prior to some individual island eradications, there are currently no established frameworks for consistent and formal approaches to such assessments. To inform the focus of future assessments, we synthesized current understanding of the potential pathways of human exposure to rodenticides and risk mitigation measures associated with island rodent eradication projects. We sought to develop this through a literature and database review that identified 153 inhabited islands where rodent eradication projects had been undertaken, of which 95 documented a priori assessments of human risks and mitigation measures. We found no reports of adverse effects from human exposure resulting from any source during discrete rodent eradication programs on inhabited islands, including direct rodenticide bait consumption, inhalation, dermal absorption, secondary or tertiary exposure. To continue advancing eradications on inhabited islands of increasing scale and proactively manage risks and perceptions, we recommend engagement processes that integrate island communities into a priori risk assessments and mitigation measure selection. [ABSTRACT FROM AUTHOR]

Invasive rodents are one of the greatest threats to island biodiversity. Eradicating these species from islands has become increasingly practicable in recent decades, primarily using anticoagulant rodenticides. However, this approach also poses risks to native wildlife, and there has been corresponding development in the management of risks to non-target wildlife species. Here we review strategies and tactics used in operational management of non-target risk, using examples from rodent eradication projects conducted on 178 islands where non-target risk assessment and mitigation was a component of the rodent eradication campaign. We identified 17 different tactics within a framework of three strategic approaches: avoidance of risk, minimization of risk, and remediation of the impact of non-target wildlife mortality. We summarize these tactics in terms of their applicability, strengths, and weaknesses for rodent eradication projects in general, plus the potential interactions with achieving rodent eradication. There remains great potential for further innovation in reducing non-target wildlife risks from rodenticide used for invasive rodent eradications on islands, supporting advancement of the social acceptability of the toolset and biodiversity conservation. [ABSTRACT FROM AUTHOR]

The Portuguese island of Selvagem Grande (Great Salvage) in Macaronesia is an important seabird breeding station in the eastern Atlantic. Significant populations of Cory's shearwater Calonectris diomedea (Scopoli, 1769), Bulwer's petrel Bulweria bulweria (Jardine & Selby, 1828) and little shearwater Puffinus assimilis baroli (Bonaparte, 1857) are present, and white-faced storm-petrel Pelagodroma marina (Latham, 1790) and Madeiran storm-petrel Oceanodroma castro (Harcourt, 1851) populations are of global significance. Selvagem Grande also provides diverse habitats for an extensive flora, including 11 endemic species. The 270-ha island was also inhabited by two alien invasive mammals: the European rabbit Oryctolagus cuniculus (Linnaeus, 1758) and the house mouse Mus musculus (Linnaeus, 1758). Both are known to have had adverse impacts on breeding seabirds and island vegetation. In 2002, the Natural Park of Madeira conducted a program using brodifacoum bait formulations aimed at rabbit and mouse eradication. Approximately 17 000 individual baiting points were established on a 12.5 × 12.5 m grid. Baits were also applied by hand “seeding” on steep slopes and cliffs where bait stations could not be placed. Rabbits were removed after a month. However, mice persisted for considerably longer and strategic bait applications against them continued for a further six months. Subsequent assessments by trapping, bait takes and systematic observation of signs over three years, has confirmed the removal of both alien invasive species. This paper presents information on these operations, on measures adopted to mitigate adverse impacts of the eradication program on important vertebrate non-target species, including Berthelot's pipit Anthus berthelotii Bolle, 1862 and a species of gecko Tarentola bischoffi Joger, 1984 and on the initial response of the island's ecosystem to the eradication of rabbits and mice. [ABSTRACT FROM AUTHOR]