Busselton Wetlands (25146)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: D1a
Year of last assessment: 2009
National site name: Busselton Wetlands
Central coordinates: Latitude: -33.6240, Longitude: 115.4138
System: marine, terrestrial
Elevation (m): 0 to 5
Area of KBA (km2): 20.6139
Protected area coverage (%): 51.82
KBA classification: Global
Legacy site: Yes
Site details
Site description: The Busselton Wetlands are a chain of coastal wetlands that stretch approximately 25 kilometres east and west of Busselton along Geographe Bay. The IBA consists of the Vasse and Wonnerup lagoons and the Broadwater. These are part of an extensively modified wetland system, now comprising an extensive, shallow (less than 1 m deep), nutrient-enriched wetland system with widely varying salinities, comprised of primarily open water fringed by samphire, rushes, flooded pastures and paperbark trees. Water levels in its two principal components, the Vasse and Wonnerup estuaries (now functioning as lagoons), are managed through the use of flood gates, with the aim of minimising flooding of adjoining lands and largely excluding seawater. Large portions of these lagoons often dry out in summer, and water quality decreases as higher temperatures and eutrophic inflows allow large phytoplankton blooms, and salinity increases as water levels drop. The Broadwater is a low-lying lagoon which fills with water over the wet winter months, and has fringing freshwater swamps. New River and associated waterways between the Broadwater and Vasse-Wonnerup have not been included in the IBA as they support low numbers of waterbirds, but they may be important for the hydrological intregrity of the system. Busselton is one of Australia's fastest developing urban areas and the IBA’s proximity to residential, farming and tourism areas presents a range of threats, management issues and opportunities. The IBA overlaps with the Vasse-Wonnerup Ramsar site but also includes the Broadwater.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.
Additional biodiversity: The IBA regularly supports large numbers of waterbirds, with a maximum count of 37,446 waterbirds in December 1998 (Lane et al. 2007). Another high count of 33,000 waterbirds was made in 1986 (DEWHA 2008) and Bamford and Bamford (1995) recorded 22,660 waterbirds in November 1994. Counts of more than 12,000 and more than 17,000 waterbirds were made in November 2007 and February 2008, respectively. Gole et al. (2008) recorded counts of 25,422 and 21,822 waterbirds in January 2008, including 12,900 Grey Teal. As counts have historically not included the Broadwater, where up to 7300 waterbirds have been recorded in recent years (C. Gole in litt. 2008), the Busselton Wetlands overall probably regularly support up to 30,000 waterbirds. More than 80 species of waterbirds have been recorded in the system, including 4750 Pacific Black Duck, 2512 Red-necked Stint and 3494 Black-winged Stilt in 1998-2000, up to 2300 Curlew Sandpiper in 1986, and more than 1% of the national population of Wood Sandpiper (72 in January 1989), Common Greenshank (200 in January 1986) and Long-toed Stint (49 in January 1988) (WAPC 2005; Lane et al. 2007; DEWHA 2008). A significant maximum count of 2300 Sharp-tailed Sandpiper was made in 1986 (WAPC 2005; DEWHA 2008) but the highest number recorded in 1998-2000 was only 800 (Lane et al. 2007). There has been one documented significant count of 998 Red-capped Plover (Lane et al. 2007) and there have been single records of the threatened Australasian Bittern and Australian Painted Snipe in 1986. The IBA supports the largest breeding colonies of Black Swan in south-western Australia, with a maximum count of 3103 in 1998-2000 (Lane et al. 2007) and a recent maximum count of 5663 in 2007 (Gole et al. 2008). There were four records each of Regent Parrot and Red-capped Parrot from 1998 to 2009 (Atlas of Australian Birds database). Non-bird biodiversity: Other native species include Water Rat, Brown Bandicoot, Western Ringtail Possum, Western Grey Kangaroo, Tiger Snake, Long-necked Tortoise, Squelching Froglet, Lea’s Froglet, Motorbike Frog, Banjo Frog and Moaning Frog. No nationally rare, threatened or endemic wetland plants have been recorded at the site. Problematic exotic plants such as Bulrush (Typha orientalis) and Arum Lily (Zantedeschia aethiopica) have become established in and around Sabina and Abba Rivers, which feed into the wetland.
Other site values: Parts of five protected areas (managed by DEC), freehold land and unallocated Crown Land (managed by the Shire of Busselton). Access to the IBA is variable. Estuarine marshland and tidal floodplain are largely on private land. Information regarding public access is available through the Department of Environment and Conservation for the Vasse and Wonnerup Lagoons, and the Shire of Busselton for the Broadwater. A number of access points for walkers and cyclists are provided on the Busselton Wetlands Trails.
Habitats
Land use: nature conservation and research | rangeland/pastureland | water management
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Coastal/Supratidal | 95 | |
| Artificial - Terrestrial | 5 |
Threats
Summary of threats to biodiversity at KBA: Improving catchment management and reducing run-off from adjacent grazing areas would help to prevent eutrophication. Planning and management of the adjacent urban development needs to consider the impact of run-off, pollution, regulated hydrology and other development pressures on these wetlands.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Agriculture & aquaculture | Livestock farming & ranching | Agro-industry grazing, ranching or farming | Ongoing |
| Natural system modifications | Dams & water management/use | Abstraction of ground water (agricultural use) | Ongoing |
| Pollution | Agricultural & forestry effluents | Nutrient loads | Ongoing |
| Residential & commercial development | Housing & urban areas | Only in the future |
Additional information
References: Bamford, A.R. and Bamford, M.J. (1994) Study of the use by waterbirds of the floodplains of the Vasse and Wonnerup Estuaries: Phase 1 Report. Como, Western Australia: Department of Conservation and Land Management. Bamford, M.J. and Bamford, A.R. (1995) Waterbirds of the floodplains of the Vasse and Wonnerup Estuaries: patterns of usage and the effects of disturbance. Final report to Department of Conservation and Land Management. DEWHA (2008) A Directory of Important Wetlands in Australia. Information Sheet on Ramsar Wetlands (RIS) for Vasse - Wonnerup System Western Australia and The Broadwater - NSW036. Downloaded from http://www.environment.gov.au/water/publications/environmental/wetlands/database/ on November 2007. Gole, C., Taylor, P. and Abbotts, S. (2008) Bird surveys of the Busselton Wetlands. Western Australian Bird Notes 125: 1-3. Jaensch R.P., Vervest, R.M. and Hewish M.J. (1988) Waterbirds in Nature Reserves of south-western Australia, 1981-1985: Reserve accounts. RAOU Report No. 30. Melbourne: RAOU. Lane, J.A.K., Clarke A.G., Pearson G.B. and Winchcombe, Y.C. (2007) Waterbirds of the Vasse Wonnerup wetlands in 1998-2000, including Ramsar status and comparisons with earlier data. Busselton, Western Australia: Department of Environment and Conservation. Western Australian Planning Commission (2005) Busselton Wetlands Conservation Strategy. Perth: Western Australian Planning Commission.
Contributors: Comments and bird counts have been contributed by Birds Australia WA volunteer observers; Bernie Masters and the Busselton Naturalists' Club volunteers; Peter Taylor and Sue Abbotts; Bruce and Anne Buchanan; and Kim Onton and colleagues at the Department of Environment and Conservation.