PROFILE FOR MANAGEMENT OF THE HABITATS AND RELATED ECOLOGICAL AND CULTURAL RESOURCE VALUES OF ERUB ISLAND January 2013 Prepared by 3D Environmental for Torres Strait Regional Authority Land & Sea Management Unit Cover image: 3D Environmental (2013) EXECUTIVE SUMMARY Erub (Darnley) Island occupies a total area of 565 ha and is formed on massively bedded basalt, the result of Pleistocene age volcanic activity. The island is part of the Eastern Group of Torres Strait Islands which includes Mer, Ugar (Stephen) and a number of small islands and sand cays. The vegetation on Erub is controlled largely by variations in soil moisture and fertility coupled with the anthropogenic influences of human occupation. Native grassland forms up to 60% of the islands vegetation with vine forest persisting in fire protected pockets and gully lines. Other vegetation types include mangrove forests and extensive areas of altered forest habitats. A total of nine natural vegetation communities, within four broad vegetation groups (natural only) and four regional ecosystems are recognised on the island, representing approximately 4% of regional ecosystems recorded across the broader Torres Strait Island landscape. Two of the ecosystems recorded are however unique to the Eastern Island Group, in particular Mer and Erub, and have no representation elsewhere in Queensland. There are also a number of highly significant culturally influenced forest types on the island which provide a window into the islands past traditional agricultural practices. Observations suggest that portions of the island have been developed as a permaculture from the time of earliest human settlement. The total known flora of 281 species comprises 193 native species and represents approximately 21% of the known flora for the Torres Strait Islands. There are 83 families with 200 genera. The 88 introduced species account for 31% of the island flora. One species of tree, Alectryon repandodentatus, is listed as Endangered under federal and state legislation with three species, Apluda mutica (a grass), Neololeba atra (a bamboo on vine thicket margins), and Operculina brownii (a vine) listed as Near-Threatened under the Queensland Nature Conservation Act 1999. A further 10 species are considered to have significance at a local and regional level. As for the majority of Torres Strait Islands there is a considerable lack of systematic survey of fauna habitats on the island. Desktop reporting indicates 112 fauna species have been reported for Erub Island including 1 frog, 20 reptile, 86 bird and 5 mammal species. Of these, 1 reptile, 1 bird and 4 mammal species are introduced, 5 species are considered significant under either state or federal legislation and 1 species of reptile, a skink (Carlia quinquencarinata) have their sole Australian representation either on Erub Island or within the broader Eastern Island Group. This can be compared with the 384 terrestrial fauna species that have been reported for the broader Torres Strait Island group which includes 14 frog, 67 reptile, 263 bird and 40 mammal species. Habitat Management Profile – Erub Island ii Within the four broad vegetation groups (or management units) identified on the island, a number of issues for future management are identified as necessary for the future biodiversity maintenance and ecological health of the island. These include: Control of the exotic weed lantana. Evidence from neighboring Murray Island suggests that with removal of fire as a regulator, this species will rapidly displace native grassland habitats on the island. Control of a number of additional invasive weeds which are also threatening biodiversity values on the island. Continued collection of floristic information, specifically those plants that are important as a traditional resource. Further active fauna survey, both as a means of monitoring for the impacts of exotic species, as well as a means to further define the extent of island scale habitat usage of a number of significant fauna species. Further survey and documentation of the complex and diverse cultural landscape on the island. It is important that any future surveys on Erub be collaborative with the Erubam Rangers and include study of traditional ecological knowledge and ethno-taxonomy. This is also relevant to recommended land management practices which must be implemented in consultation with the island PBC in a culturally acceptable manner. Habitat Management Profile – Erub Island iii ACKNOWLEDGEMENTS The project has been funded by through the Land and Sea Management Unit of the Torres Strait Regional Authority. Our thanks are extended for the support and guidance of Tony O’Keeffe and Michael Bradby of TSRA who administered the project and provided valuable input throughout. 3d Environmental also wish to acknowledge all Erubam Elders and thank the Erubam Le PBC and community for access to their land. Much appreciation is also given to the Erubam Rangers George Romana, Amos Sipi and Aaron Ketchell for assistance in the field. Input in regard to the islands cultural background and assistance in the field was provided by Dr Garrick Hitchcock. Fauna information was provided by Terry Reis. Mr Peter Stanton provided the text for fire in the ecological landscape. Dr Paul Forster and staff of the Queensland Herbarium assisted with identification of plant specimens and advice on the distribution and ecology of significant species. Barbara Waterhouse and Steven McKenna of the Australian Quarantine Inspection Service provided valuable information on the occurrence and distribution of weeds. All members of the expert technical panel provided essential input into the process and their contribution is appreciated. Habitat Management Profile – Erub Island iv Table of Contents 1.0 Introduction............................................................................................................................... 8 1.1 Cultural Setting .......................................................................................................... 8 1.2 Geographic Setting .................................................................................................... 8 1.3 Geological Context ..................................................................................................... 8 2.0 Methods ................................................................................................................................... 10 3.0 Aims and Objectives .............................................................................................................. 10 4.0 Legislative and Policy Considerations ................................................................................ 10 5.0 Vegetation and Flora .............................................................................................................. 13 5.1 Vegetation Groups and Mapping ............................................................................. 14 5.2 Flora Species ........................................................................................................... 17 5.2.1 Flora Species with Biodiversity Significance ............................................................ 17 5.2.2 Introduced Plants ..................................................................................................... 21 5.2.3 Plants with Cultural Significance .............................................................................. 25 6.0 Fauna (Animals) ..................................................................................................................... 25 6.1 Culturally Important Animal (Fauna) Species .......................................................... 26 6.2 Animal (Fauna) Habitat Values ................................................................................ 26 6.3 Animal (Fauna) Species with Conservation Significance ........................................ 27 6.3.1 Critically Endangered, Endangered, Vulnerable and Near-Threatened Species .... 28 6.3.2 Profiles of Significant Known from or Possibly Occurring on Erub Island ............... 29 6.3.3 Migratory Animal Species ........................................................................................ 34 6.3.4 Additional possible Migratory species ...................................................................... 35 6.3.5 Species of Regional Significance............................................................................. 36 6.4 Pest Animal (Fauna) Species .................................................................................. 36 6.5 Threats to Fauna (Animals) and Habitat .................................................................. 38 6.6 Future Priorities ........................................................................................................ 38 7.0 The Role of Fire in Savanna Landscapes ............................................................................ 39 8.0 Erub Island as a Landscape in Balance ............................................................................... 40 9.0 Management Profiles for Erub Island Habitats ................................................................... 43 9.1 Evergreen Vine Thicket ............................................................................................ 43 9.1.1 Status of Ecological Knowledge............................................................................... 43 9.1.2 Ecological / Cultural Considerations ........................................................................ 43 9.1.3