Owingup Swamp and Boat Harbour Wetlands (26490)
Australia, Australasia
Site overview
KBA status: confirmed
Year of last assessment: 2009
National site name: Owingup Swamp and Boat Harbour Wetlands
Central coordinates: Latitude: -35.0047, Longitude: 117.0755
System: marine, terrestrial
Elevation (m): 7 to 18
Area of KBA (km2): 4.43989
Protected area coverage (%): 99.63
KBA classification: Global/Regional TBD
Legacy site: Yes
Site details
Site description: The IBA consists of Owingup Swamp and the smaller wetlands around nearby Boat Harbour Road, located approximately 25 km south-south-west of Denmark in Western Australia. The IBA has been defined to include the whole Owingup Swamp complex and all of about ten smaller wetlands to the south-east, either side of Boat Harbour Road, although not all have been surveyed for bitterns. The wetlands are permanent or near-permanent, of shallow depth and exhibit seasonal changes in salinity from freshwater in winter-spring to brackish in summer-autumn. Australasian Bitterns are confined to sedgelands dominated by Baumea articulata or Gahnia trifida, but the wetlands also support heathland, scrub and forest communities. The IBA has a Mediterranean climate with dry summers and wet winters.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas)
Additional biodiversity: Forty waterbird species have been recorded at Owingup Swamp with an additional five waterbird species recorded in the surrounding wetland system. Ten waterbird species have been recorded breeding in the area including the near threatened Blue-billed Duck. Counts of up to six Blue-billed Duck were made at Owingup Swamp in 1992 (Jaensch 1992a; Jaensch and Clarke 1993). There were seven Long-toed Stint at Owingup Swamp in January 1988. The maximum number of waterbirds recorded at Owningup Swamp was 1457 in March 1991, including 1200 Eurasian Coot (Jaensch 1992a, 1992b; DEWHA 2008). Terrestrial species recorded in the area include Western Rosella, Western Thornbill, Red-winged Fairy-wren, Western Spinebill and Red-eared Firetail (Atlas of Australian Birds database). Non-bird biodiversity: More than 50 species of plant, at least eight species of fish and more than 40 species of macroinvertebrates have been recorded in the IBA (Aquatic Research Laboratory 1992; Jaensch 1992a, b). Owingup Swamp supports the largest remaining mature stand of Agonis juniperina forest (Robinson 1992) and a nearby swamp supports one of the largest known populations of the nationally threatened orchid Diuris drummondii (Jaensch and Watkins 1999). The Owingup Swamp system is considered a major nursery area for freshwater and estuarine fishes (DEWHA 2008).
Other site values: State government with management the responsibility of the Department of Environment and Conservation.
Habitats
Land use: nature conservation and research (100%)
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Coastal/Supratidal | 100 |
Threats
Summary of threats to biodiversity at KBA: Monitor salination, eutrophication and siltation of wetlands and take remedial action if necessary. Investigate the probable impacts of damming of the Kent River on the ecology of the wetlands, and particularly the Australasian Bittern population.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Natural system modifications | Dams & water management/use | Large dams | Ongoing |
| Natural system modifications | Fire & fire suppression | Increase in fire frequency/intensity | Ongoing |
Additional information
References: Aquatic Research Laboratory (1992) Survey of the macroinvertebrate fauna and water chemistry of permanent lakes of the south coast of Western Australia. Unpublished report. Aquatic Research Laboratory, University of Western Australia. Perth: Department of Conservation and Land Management. DEWHA (2008) A Directory of Important Wetlands in Australia. Owingup Swamp System - WA108. Downloaded from http://www.environment.gov.au/water/publications/environmental/wetlands/database/ in December 2008. Jaensch, R.P. (1992a) Waterbirds in wetlands on the south coast of Western Australia, summer 1991-2. Woodvale, Western Australia: Department of Conservation and Land Management. Jaensch, R.P. (1992b) Fishes in wetlands on the south coast of Western Australia. Unpublished report. Perth: Department of Conservation and Land Management. Jaensch, R.P. and Clarke, A. (1993) Waterbirds breeding in spring 1992 in wetlands on the south coast of Western Australia. Woodvale, Western Australia: Department of Conservation and Land Management. Jaensch, R.P. and Watkins, D.G. (1999) Nomination of additional Ramsar Wetlands in Western Australia: Final Report. Perth: Department of Conservation and Land Management. Robinson, C.J. (1992) Survey and inventory of the wetland flora of the south coast of Western Australia. Unpublished report. Perth: Department of Conservation and Land Management.
Contributors: Roger Jaensch of Wetlands International provided data and comments.