Document ID: chunk:federal_register_of_legislation:F2009L02536:reg:2:p1
Version: federal_register_of_legislation:F2009L02536
Segment Type: reg
Provision Reference: reg 2 (pt 1/3)
Character Range: 5039–7936

2                        Background

2.1                   Threat abatement plans
The Australian Government develops threat abatement plans and facilitates their implementation under the EPBC Act. The Department of the Environment, Water, Heritage and the Arts has a role to assess the potential for and promotion of the partnerships between government agencies and other stakeholders that are required to conduct the actions identified in the plans.

A threat abatement plan for exotic rodents on islands can be more focused than plans for other invasive species because the sites for action are clearly identified, the control tools are available, the impacts of the rodents are mostly on biodiversity rather than on production values, and in many cases the pest can be eradicated. Nevertheless, each island has unique circumstances, not the least being the presence of people on many candidate islands. Therefore, like other plans, this plan also advocates the social and economic aspects of management.

Australia has seven islands, all with exotic rodents, larger than 100 000 ha, the upper cut-off size for this plan. However, eradication on islands this size is currently impractical so, although they are excluded from this plan, that should not preclude sustained control at priority sites on these larger islands if that strategy is justified by local needs.

2.2                   Exotic rodents on Australian islands
The four exotic rodent species in this threat abatement plan have variously invaded over 80% of the world's major island archipelagos, and have been responsible for many of the extinctions and ecosystem changes that have occurred on these important fragments and refuges for biodiversity. Exotic rodents continue to invade islands, but since the 1980s, when techniques to eradicate them were developed in New Zealand, the rate at which they have been eradicated has exceeded the rate of invasion of new islands. To date, invasive rodents have been eradicated from 350 islands in 21 countries around the world.

Australia has over 8300 islands under 100 000 ha, of which at least 133 are now known to have one or more species of exotic rodents. House mice, ship rats and the two together are by far the most common rodents on Australian islands. Exotic rodents have been eradicated from 39 islands, almost all from Western Australia.

About 31% of these 133 islands are connected to or are within easy swimming distance (for a ship rat) of the mainland. Thus, eradication will be difficult on this subset of islands unless backed by effective 'border' control and quarantine measures.

About 57% of the islands are entirely or substantially managed under various reserved tenures, about 34% are privately owned or leased, and about 9% are owned by indigenous people. Many islands that are important for biodiversity have permanent residents. Thus governments, private