Resource Condition Report for a Significant Western Australian Wetland Hutt Lagoon 2009 Figure 1 – A view across the water body at Hutt Lagoon, coloured pink by alga. This report was prepared by: Anna Nowicki, Technical Officer, Department of Environment and Conservation, PO Box 51, Wanneroo 6946 Adrian Pinder, Senior Research Scientist, Department of Environment and Conservation, PO Box 51, Wanneroo 6946 Stephen Kern, Botanist, Department of Environment and Conservation, Locked Bag 104 Bentley Delivery Centre 6983 Glen Daniel, Environmental Officer, Department of Environment and Conservation, Locked Bag 104 Bentley Delivery Centre 6983 Invertebrate sorting and identification by: Nadine Guthrie, Research Scientist, Department of Environment and Conservation, PO Box 51, Wanneroo 6946 Ross Gordon, Project Officer, Department of Environment and Conservation, PO Box 51, Wanneroo 6946 Prepared for: Inland Aquatic Integrity Resource Condition Monitoring Project, Strategic Reserve Fund, Department of Environment and Conservation August 2009 Suggested Citation: Department of Environment and Conservation (DEC) (2009). Resource Condition Report for a Significant Western Australian Wetland: Hutt Lagoon. Department of Environment and Conservation, Perth, Western Australia. Contents 1. Introduction.........................................................................................................................1 1.1. Site Code ...............................................................................................................1 1.2. Purpose of Resource Condition Report...................................................................1 1.3. Relevant Legislation and Policy ..............................................................................1 2. Overview of Hutt Lagoon.....................................................................................................4 2.1. Location and Cadastral Information ........................................................................4 2.2. IBRA Region ..........................................................................................................4 2.3. Climate...................................................................................................................5 2.4. Wetland Type .........................................................................................................5 2.5. Directory of Important Wetlands in Australia Criteria ...............................................5 2.6. Values of Hutt Lagoon ............................................................................................6 3. Critical Components and Processes of the Ecology of Hutt Lagoon .....................................7 3.1. Geology and Soils ..................................................................................................8 3.2. Hydrology...............................................................................................................8 3.3. Water Quality .........................................................................................................8 3.4. Phytoplankton ........................................................................................................9 3.5. Benthic Plants ........................................................................................................9 3.6. Littoral Vegetation ..................................................................................................9 3.7. Aquatic Invertebrates............................................................................................11 3.8. Fish......................................................................................................................15 3.9. Waterbirds............................................................................................................15 3.10. Terrestrial Vertebrates..........................................................................................15 4. Interactions between Ecological Components at Hutt Lagoon............................................15 5. Threats to the Ecology of Hutt Lagoon ..............................................................................19 6. Knowledge Gaps and Recommendations for Future Monitoring.........................................23 References................................................................................................................................24 Appendix 1 – Vegetation Condition............................................................................................26 Appendix 2 – Herbarium Plant Records .....................................................................................27 1. Introduction This Resource Condition Report (RCR) was prepared by the Inland Aquatic Integrity Resource Condition Monitoring (IAI RCM) project. It describes the ecological character and condition of Hutt Lagoon, an expansive coastal brine lake in the state’s Midwest. Hutt Lagoon was selected as a study site for the IAI RCM project because it is listed in the Directory of Important Wetlands in Australia (DIWA) as an important stop-over for migratory waterbirds (Environment Australia 2001). It is also a proposed Natural Diversity Recovery Catchment, a program of the Department of Environment and Conservation (DEC) that aims to recover and protect significant natural areas, particularly wetlands, from salinity. 1.1. Site Code Inland Aquatic Integrity Resource Condition Monitoring Project: RCM028. Directory of Important Wetlands in Australia: WA035. OzCoasts Estuary ID: 908. Salinity Action Plan Wetland Biological Survey: SPS189. Hutt Catchment Survey: HUT012. 1.2. Purpose of Resource Condition Report This RCR provides a summary of information relevant to the ecology of Hutt Lagoon. This information is then used to describe the drivers of, and threats to, the wetland ecosystem. The resultant ‘snapshot’ of ecological character will provide context for future monitoring of the lagoon and assist with assessing the effectiveness of management planning and actions at the site. 1.3. Relevant Legislation and Policy This section provides a summary of the legislation and policy that may be relevant to the management of Hutt Lagoon. International Migratory bird bilateral agreements and conventions Australia is party to a number of bilateral agreements, initiatives and conventions for the conservation of migratory birds that may be relevant to Hutt Lagoon. The bilateral agreements are: JAMBA - The Agreement between the Government of Australia and the Government of Japan for the Protection of Migratory Birds in Danger of Extinction and their Environment, 1974; CAMBA - The Agreement between the Government of Australia and the Government of the People’s Republic of China for the Protection of Migratory Birds and their Environment 1986; ROKAMBA - The Agreement between the Government of Australia and the Republic of Korea for the Protection of Migratory Birds and their Environment, 2006; and The Bonn Convention on Migratory Species - The Bonn Convention adopts a framework in which countries with jurisdiction over any part of the range of a particular species co-operate to prevent migratory species becoming endangered. For Australian purposes, many of the species are migratory birds. 1 Western Australia state legislation Wildlife Conservation Act 1950 This Act provides for the protection of wildlife. All fauna (animals native to Australia) in Western Australia are protected under section 14 and all flora (plants native to Western Australia) are protected under section 23 of the Wildlife Conservation Act 1950 . The Act establishes licensing frameworks for the taking and possession of protected fauna, and establishes offences and penalties for interactions with fauna. Conservation and Land Management Act 1987 This Act is administered by the State Department of Environment and Conservation (DEC) and applies to public lands. It sets the framework for the creation and management of marine and terrestrial parks, reserves and management areas in Western Australia, and deals with the protection of flora and fauna within reserve systems. 2 Legend x WA Townsites A! RCM survey site Principal Road Secondary Road Minor Road Track DIWA Site Lake Subject to Inundation Swamp DEC Region Boundary National Park Nature Reserve Other Crown Reserves Unallocated Crown Land Pastoral Leases !! Live Mine lease ! ! !! Pending Mine lease Figure 2 – Aerial photograph showing the position of the survey location at Hutt Lagoon. Also shown, the position of the site relative to surrounding towns (upper insert) and other IAI RCM survey sites (lower insert). 3 2. Overview of Hutt Lagoon 2.1. Location and Cadastral Information Hutt Lagoon lies 2 km northeast of Port Gregory and approximately 50 km east-southeast of Kalbarri. The surrounding land is a complex mixture of tenure types, with the southern end of the lake a crown lease and the northern end a ‘water feature’ that is not vested in any management authority. Unallocated Crown Land lies to the north, south and west of the lagoon as well as forming a bridge across its centre. East of the lagoon is freehold land, mainly used for wheat and sheep farming, but also containing a large garnet mine. There is a shire reserve on the lagoon’s south east margin and the Gregory townsite on its south west. The road to Kalbarri (George Grey Drive) runs along the eastern margin of the lagoon (Figure 2, Figure 3). Figure 3 – Tenure of the Hutt Lagoon area. 2.2. IBRA Region Hutt Lagoon lies within the Geraldton