Citation: Hale, J., 2008, Ecological Character Description of the Ord River Floodplain Ramsar Site, Report to the Department of Environment and Conservation, Perth, Western Australia. Funding for the development of this document was sourced jointly from the Natural Heritage Trust (NHT) and the State and Commonwealth contributions to the National Action Plan for Salinity and Water Quality (NAP). NHT and NAP are jointly administered by the Australian Government departments of Agriculture, Fisheries and Forestry and the Environment, Water, Heritage and the Arts and the WA Natural Resource Management Office. In-kind contributions were gratefully received from the organisations represented on the Technical Advisory Group. Expert Advice: Associate Professor Mark Lund, Edith Cowan University Associate Professor Eric Paling, Murdoch University Dr Roger Jaensch, Wetlands International Dr David Morgan, Murdoch University Dr Halina Kobryn, Murdoch University Acknowledgements: Mr Michael Coote, Department of Environment and Conservation Mr Robert Cossart, Department of Water Ms Rachel Green, Fisheries Western Australia Ms Sarah Greenwood, Department of Environment and Conservation Ms Jennifer Higbid, Department of Environment and Conservation Mr Ben Malseed, Department of Water Mr Daryl Moncrieff, Department of Environment and Conservation Ms Jeanette Muirhead, Department of Environment, Water, Heritage and the Arts Mr Duncan Palmer, Department of Water Dr Barbara Robson, CSIRO Mr Troy Sinclair, Department of Environment and Conservation Dr Clare Taylor, CSIRO Mr Gareth Watkins, Department of Environment and Conservation 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. 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 ................................................................................................................................... 1 Abbreviations ........................................................................................................................... 4 Executive Summary ................................................................................................................ 5 1. Introduction ........................................................................................................................ 10 1.1 Site details ......................................................................................................................... 10 1.2 Statement of purpose ........................................................................................................ 10 1.3 Relevant treaties, legislation and regulations .................................................................... 14 1.4 Method ............................................................................................................................... 16 2. General Description of the Ord River Floodplain Ramsar Site ..................................... 17 2.1 Location ............................................................................................................................. 17 2.2 Land tenure........................................................................................................................ 19 2.3 Climate ............................................................................................................................... 20 2.4 Ramsar criteria .................................................................................................................. 23 2.4.1 Criteria under which the site was designated (1990) ................................................. 23 2.4.2 Current situation and additional criteria met ............................................................... 24 2.5 Wetland types .................................................................................................................... 26 3. Critical Components, Processes, Benefits and Services .............................................. 28 3.1 General Description ........................................................................................................... 28 3.2 Critical Components and Processes ................................................................................. 29 3.2.1 Identifying critical components and processes ........................................................... 29 3.2.2 Geomorphology .......................................................................................................... 31 3.2.3 Hydrology.................................................................................................................... 35 3.2.4 Water quality ............................................................................................................... 41 3.2.5 Phytoplankton ............................................................................................................. 45 3.2.6 Vegetation................................................................................................................... 46 3.2.7 Invertebrates ............................................................................................................... 51 3.2.8 Fish ............................................................................................................................. 52 3.2.9 Waterbirds .................................................................................................................. 56 3.2.10 Crocodiles ................................................................................................................. 61 3.3 Benefits and services ........................................................................................................ 63 3.3.1 Overview of benefits and services .............................................................................. 63 3.3.2 Cultural and economic services and benefits ............................................................. 64 3.3.3 Identifying critical ecosystem services and benefits ................................................... 65 3.3.4 Supports diverse physical habitat types ..................................................................... 66 3.3.5 Supports threatened species ...................................................................................... 67 3.3.6 Supports critical life stages ......................................................................................... 68 3.3.7 Supports abundant and diverse waterbirds ................................................................ 71 3.3.8 Supports diverse fish populations .............................................................................. 71 4. How the Ord River Floodplain System Works: Interactions between components, processes & services ............................................................................................................ 72 4.1 Primary determinants of ecological character ................................................................... 72 4.2 Abiotic components ........................................................................................................... 73 4.3 Habitat ............................................................................................................................... 77 i 5. Limits of Acceptable Change ........................................................................................... 80 5.1 Process for setting LAC ..................................................................................................... 80 5.2 LAC for the Ord River Floodplain Ramsar site .................................................................. 84 6. Threats to the Ecological Character of the Ord River Floodplain Ramsar site ........... 87 6.1 Water resource development and management ..............................................................