Controlling or eradicating pest species on islands can result in significant conservation benefits. The aim of this project is to identify the islands with the greatest need for pest management action.
Work over the past decade has demonstrated eradication efforts on Tasmania’s off-shore islands can be highly effective, with successful eradications occurring on Macquarie Island (cats, rabbits, rodents), Tasman Island (cats), Wedge Island (cats), Big Green Island (rats), George Rocks (rats and weeds) and Roydon Island (weeds). Threats that continue to impact Tasmania’s off-shore islands include a range of vertebrate pests – rabbits, feral cats and rodents (rats and mice); and weeds, including Weeds of National Significance (WoNS).
In 2022, the Invasive Species Branch was successful in securing project funding from the Federal Funding Agreement - Environment Enhancing National Pest Animal and Weed Management – Tranche 2 – Supporting Communities Manage Pest Animals and Weeds Program (2022 to 2025). This Commonwealth funding is worth $800,000 over the course of the project aiming at protecting the economic and natural assets of Tasmania's off-shore islands from the impact of vertebrate pests and weeds.
Infestation of mirror bush (Coprosma repens) Fisher Island, Flinders Island.
Tasmania’s many islands show a diverse range of size, habitats, tenure, and values. There are at least 6,000 points of land (islands, rocks, and reefs) which appear above the high tide mark. For the purposes of this project, islands are marine-based and provide habitat for seabirds, other terrestrial fauna and in most cases include vegetation. They have a natural protective barrier, being surrounded by the sea.
A feral cat with a seabird captured by a remote camera.
Feral species have a great impact on the native species which inhabit the islands. The photos above show feral cats predating on native seabirds which is predominantly the diet of cats on islands. The presence of feral cats on offshore islands poses a severe threat to native seabird populations, leading to predation, population declines, ecosystem disruptions, and even extinction of endemic species.
The project has been targeting the eradication of vertebrate pests that both predate on native fauna (e.g. seabirds) and destroy vital habitat. A range of techniques and technologies will be developed in the detection, surveillance, control and management of invasive vertebrates and plants (e.g. snap traps, bait, cameras). A priority list of islands will be targeted based on a predetermined criteria which include:
- Presence of a threatened species
- The threatened habitat
- High value island-significant species or population
- Imminent threat of loss of a species
The target species from identified priority islands will include:
- Weed species - Mirror bush (Coprosma repens) and African boxthorn (Lycium ferocissimum).
- Pest animals - feral cat (Felis catus), rabbit (Oryctolagus cuniculus), rats (Rattus spp.) and mice (Mus musculus).
Little Dog Tern Rock before weeding efforts.
Little Dog Tern Rock after weeding.
Pictured above are before and after photos of weed removal work undertaken in Little Dog (Tern) Rock for mirror bush.
The Invasive Species Branch continues to assess and review the data collected through the survey and monitoring work and implement work program activities to deliver the outcomes of the project.
For further information on this project contact:
Invasive Species Branch
Email: invasivespecies@nre.tas.gov.au
Or phone: 03 6165 3777