Ecosure Pty Ltd for the Department of the Environment, Water, Heritage and the Arts, 2009
Individual chapters and appendices
- Executive summary and table of contents (PDF - 93 KB) | (RTF - 1.56 MB)
- Chapter 1 (PDF - 141 KB) | (RTF - 1.43 MB)
- Chapter 2 (PDF - 172 KB) | (RTF - 4.88 MB)
- Chapter 3 (PDF - 110 KB) | (RTF - 1.67 MB)
- Chapter 4 (PDF - 1.35 MB) | (RTF - 4.24 MB)
- Chapter 5 (PDF - 82 KB) | (RTF - 1.53 MB)
- Chapter 6 (PDF - 76 KB) | (RTF - 1.52 MB)
- Chapter 7 (PDF - 99 KB) | (RTF - 1.50 MB)
- Chapter 8 (PDF - 71 KB) | (RTF - 1.41 MB)
- Chapter 9 (PDF - 135 KB) | (RTF - 1.49 MB)
- Appendices a-c - species lists (PDF - 327 KB) | (RTF - 2.81 MB)
- Appendix d - GIS data preparation (PDF - 91 KB) | (RTF - 1.57 MB)
- Appendix e - fauna impacts (PDF - 119 KB) | (Excel - 266 KB)
- Appendix f - flora impacts (PDF - 94 KB) | (Excel - 158 KB)
- Appendix g - all maps of priority areas [low resolution] (PDF - 256 KB)
- Appendix g - Map 1 - all priority areas in Australia [high resolution] (PDF - 1.55 MB)
- Appendix g - Map 2 - priority areas in the Northern Territory [high resolution] (PDF - 1.81 MB)
- Appendix g - Map 3 - priority areas in Queensland [high resolution] (PDF - 1.76 MB)
- Appendix g - Map 4 - priority areas in New South Wales [high resolution] (PDF - 1.08 MB)
- Appendix g - Map 5 - priority areas in Victoria [high resolution] (PDF - 1.49 MB)
- Appendix g - Map 6 - priority areas in Tasmania [high resolution] (PDF - 1.66 MB)
- Appendix g - Map 7 - priority areas in South Australia [high resolution] (PDF - 1.31 MB)
- Appendix g - Map 8 - priority areas in Western Australia [high resolution] (PDF - 1.82 MB)
The Australian Government Department of the Environment, Water, Heritage & the Arts (DEWHA) required an independent national assessment of the conservation value of Australia's offshore islands, and the specific vertebrate pest management issues on these islands. Australia has approximately 8 300 offshore islands, including small rocks which are often associated with larger islands; too many for effective investment of funds to secure biodiversity values into the future. A priority list of 100 islands of high conservation status is needed to help guide future government investment on offshore islands.
This report presents our assessment of the conservation status of Australia's offshore islands. In collaboration with Dr Ray Pierce (Eco Oceania Ltd) we conducted a detailed assessment of key island biodiversity, comprising threatened species listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and/or state/territory legislation, as well as listed EPBC Marine and/or Migratory species (Bonn, CAMBA, JAMBA and/or ROKAMBA). This 'biodiversity value' assessment was followed by an evaluation of the types and status of vertebrate pests on those islands (intrinsic feral 'value'), supplemented by a matrix of species-specific impacts, island by island. For example, a non-climbing Red Fox will have a greater impact on small ground-dwelling mammals than it will on arboreal species.
Herewithin we provide:
- a priority list of 100 high conservation status islands of at least 200 ha in area, indicating the top and lower 50 qualifying islands
- a summary list of additional islands that were fully evaluated, but did not make the priority 100 list
- a summary list of smaller islands (< 200 ha) which we believe should be examined more closely
- profiles for the 100 priority islands, including their geographical context, additional ecological and environmental values, management issues and our island specific recommended actions, and
- overall recommendations to help guide future DEWHA investment.
Our results represent the climatic, geographical, topographical, biological and ecological diversity of Australia's offshore islands. Priority islands (> 200 ha) occur in the oceans all around Australia, in all states and territories with coastline and offshore waters:
- 26 are in Queensland
- 23 are in Western Australia
- 19 are in the Northern Territory
- 15 are in Tasmania
- 11 are in Victoria
- 5 are in South Australia, and
- 1 is in NSW (Lord Howe Island).
Priority islands ranged in area from 202 ha (Boodie Island, WA) to 578 577 ha (Melville Island, NT). Some are near the mainland (e.g. Bribie and North Stradbroke islands, QLD), and may even be linked by sand spits at low tides (e.g. Dolphin Island, WA), others are extremely remote (e.g. Macquarie, TAS). Some islands qualified in the list based largely on the number and type of Migratory and/or Marine seabirds and/or shorebirds that utilise the islands for breeding (e.g. Phillip Island, VIC). Others have endangered small mammals that are at risk of extinction or already no longer occur on the mainland (e.g. Bernier and Dorre islands, WA and Groote Island, NT). Others still had significant biodiversity representation among both fauna and flora (e.g. Fraser Island, QLD and French Island, VIC). Detailed consideration of smaller islands (< 200 ha) may yield a different distribution of high conservation status islands. However, any island assessment is limited by the available data. Many islands are little surveyed, and others that are well surveyed do not have easily accessible data.
Worldwide, offshore islands provide unique ecosystems and present the opportunity for protecting species that may be driven to extinction on mainlands where feral pests are much more difficult to eradicate. Australia's islands are no exception, and their potential importance for safeguarding Australia's native biodiversity cannot be overstated. Vertebrate pests are one of the most pressing challenges placing refugial island biodiversity at risk. Many commendable pest management plans have already been implemented on islands (e.g. Lord Howe Island, NSW and Macquarie Island, TAS), and feral pests have been eradicated from some (e.g. islands in the Dampier Archipelago, WA), but many, if not all, are in need of additional resources to ensure that pest free status is achieved where possible, and maintained if achieved. For others, maintaining low feral populations is the most practicable option.
We hope that this assessment provides a solid foundation on which investment decisions can be made for Australia's offshore islands. However, we would like to emphasise that this assessment is a snapshot in time, and we encourage the ongoing maintenance of island biodiversity and feral species datasets so that threats to island biodiversity can be continually assessed and appropriate measures taken to safeguard our ecological heritage into the future.