Current view: Text account
Site description (2008 baseline):
Site location and context
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.
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).
Pressure/threats to key biodiversity
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.
Owingup Nature Reserve overlaps the IBA.
State government with management the responsibility of the Department of Environment and Conservation.
Roger Jaensch of Wetlands International provided data and comments.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Owingup Swamp and Boat Harbour Wetlands (Australia). Downloaded from
https://datazone.birdlife.org/site/factsheet/owingup-swamp-and-boat-harbour-wetlands-iba-australia on 26/12/2024.
