Threat Abatement Plan to reduce the impacts of exotic rodents on biodiversity on Australian offshore islands of less than 100 000 hectares 2009 (Cth)

THREAT ABATEMENT PLAN

to reduce the impacts of exotic rodents on biodiversity on Australian offshore islands of less than 100 000 hectares

2009

Contents

1 Summary 2 Background 2.1 Threat abatement plans 2.2 Exotic rodents on Australian islands 2.3 Impacts on biodiversity 2.4 Managing the threat 3 Threat abatement 3.1 Goal 3.2 Objectives 3.3 Actions 3.3.1 Actions to set priorities and plan strategic options 3.3.2 Actions to achieve eradication 3.3.3 Actions to achieve sustained control 3.3.4 Actions to prevent invasion or reinvasion 3.3.5 Actions to achieve outreach and public education 3.4 Research and information needs 4 Implementation 4.1 Implementing the plan 4.2 Duration and cost 4.3 Evaluating progress 5 References Appendix A Threatened species affected by exotic rodents on islands

1 Summary

1.1 Rationale for a threat abatement plan Human dispersal and colonisation over the last few millennia has spread four species of Eurasian rodents to many of the world's islands. These rodents are: ship, or black, rats (Rattus rattus); Norway, or brown, rats (R. norvegicus); Pacific rats (R. exulans); and house mice (Mus musculus). Together with other exotic pests, they are a major threat to native biodiversity on islands. Australian islands have been no exception, especially since European colonisation. Exotic rodents, particularly ship rats and perhaps mice, have been a key (and often the critical) cause of extinction, extirpation (local population loss) and decline of many native species, adverse changes to island ecosystems, as well as economic damage to island peoples' livelihoods and potentially to their health. The presence of rodents on islands also precludes many positive options to restore island values, and their presence on mainland Australia and elsewhere presents an ongoing risk to biodiversity. For Australian islands not currently invaded there is also a high risk.