Lakes Argyle and Kununurra Ramsar Site Ecological Character Description Citation: Hale, J. and Morgan, D., 2010, Ecological Character Description for the Lakes Argyle and Kununurra Ramsar Site. Report to the Department of Sustainability, Environment, Water, Population and Communities, Canberra. Acknowledgements: Danny Rogers, Australasian Waders Studies Group (expert advice) Halina Kobryn, Murdoch University (mapping and GIS) The steering committee was comprised of representatives of the following organisations: • Department of the Environment, Water, Heritage and the Arts • WA Department of Environment and Conservation (Kununurra) • WA Department of Water (Kununurra) • Shire of Wyndham East Kimberley Introductory Notes This Ecological Character Description (ECD Publication) has been prepared in accordance with the National Framework and Guidance for Describing the Ecological Character of Australia’s Ramsar Wetlands (National Framework) (Department of the Environment, Water, Heritage and the Arts, 2008). The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) prohibits actions that are likely to have a significant impact on the ecological character of a Ramsar wetland unless the Commonwealth Environment Minister has approved the taking of the action, or some other provision in the EPBC Act allows the action to be taken. The information in this ECD Publication does not indicate any commitment to a particular course of action, policy position or decision. Further, it does not provide assessment of any particular action within the meaning of the Environment Protection and Biodiversity Conservation Act 1999 (Cth), nor replace the role of the Minister or his delegate in making an informed decision to approve an action. The Water Act 2007 requires that in preparing the [Murray-Darling] Basin Plan, the Murray Darling Basin Authority (MDBA) must take into account Ecological Character Descriptions of declared Ramsar wetlands prepared in accordance with the National Framework. This ECD Publication is provided without prejudice to any final decision by the Administrative Authority for Ramsar in Australia on change in ecological character in accordance with the requirements of Article 3.2 of the Ramsar Convention. Disclaimer While reasonable efforts have been made to ensure the contents of this ECD are correct, the Commonwealth of Australia as represented by the Department of Sustainability, Environment, Water, Population and Communities does not guarantee and accepts no legal liability whatsoever arising from or connected to the currency, accuracy, completeness, reliability or suitability of the information in this ECD. Note: There may be differences in the type of information contained in this ECD publication, to those of other Ramsar wetlands. Table of Contents Glossary ..................................................................................................................................... iii List of Abbreviations .................................................................................................................. vi Executive Summary .................................................................................................................. vii 1. Introduction ............................................................................................................................ 1 1.1 Site details........................................................................................................................ 1 1.2 Statement of purpose ....................................................................................................... 1 1.3 Relevant treaties, legislation and regulations .................................................................. 3 1.4 Method ............................................................................................................................. 5 2. General Description of the Lakes Argyle and Kununurra Ramsar Site ................................. 7 2.1 Location ............................................................................................................................ 7 2.2 Land tenure ...................................................................................................................... 7 2.3 Wetland types ................................................................................................................ 10 2.4 Ramsar criteria ............................................................................................................... 13 2.4.1 Criteria under which the site was designated ......................................................... 13 2.4.2 Assessment based on current information and Ramsar criteria ............................. 14 3. Critical Components and Processes ................................................................................... 19 3.1 Identifying critical components and processes .............................................................. 19 3.2 Essential elements ......................................................................................................... 21 3.2.1 Climate .................................................................................................................... 21 3.2.2 Geomorphology ....................................................................................................... 23 3.2.3 Water quality ........................................................................................................... 25 3.2.4 Wetland vegetation .................................................................................................. 27 3.2.5 Invertebrates ........................................................................................................... 30 3.3 Critical components and processes ............................................................................... 30 3.3.1 Hydrology ................................................................................................................ 31 3.3.2 Fish .......................................................................................................................... 32 3.4.3 Waterbirds ............................................................................................................... 34 3.5.4 Freshwater Crocodiles ............................................................................................ 36 3.6.5 Other fauna ............................................................................................................. 37 4 Ecosystem services .............................................................................................................. 38 4.1 Overview of benefits and services ................................................................................. 38 4.2 Identifying critical ecosystem services and benefits ...................................................... 39 4.3 Critical services .............................................................................................................. 39 4.3.1 Provides physical habitat for large numbers of waterbirds ..................................... 39 4.3.2 Priority wetland species – supports migratory birds ................................................ 41 4.3.3 Biodiversity – supports fish ..................................................................................... 43 4.3.4 Distinct wetland species - Crocodiles ...................................................................... 44 4.3.5 Water supply ........................................................................................................... 45 4.4 Non-critical services ....................................................................................................... 45 4.4.1 Commercial fishing .................................................................................................. 45 4.4.2 Recreation and tourism ........................................................................................... 46 4.4.3 Indigenous cultural values ....................................................................................... 46 4.5 Conceptual models ........................................................................................................ 47 5. Threats to Ecological Character .......................................................................................... 50 5.1 Invasive species ............................................................................................................. 52 5.1.1 Cane toad (Chaunus [Bufo] marinas) ...................................................................... 52 5.1.1 Redclaw crayfish (Cherax quadricarinatus) ............................................................ 52 5.1.3 Weeds ..................................................................................................................... 53 5.2 Water resource development ......................................................................................... 54 5.3 Commercial fishing ........................................................................................................ 54 5.4 Urban development and stormwater .............................................................................. 55 5.5 Fire ................................................................................................................................. 55 5.6 Summary of threats ........................................................................................................ 55 6. Limits of Acceptable