Broad Sound


Site description (2008 baseline):

Site location and context
The IBA consists of a complex of marine, estuarine and freshwater wetlands in and around Broad Sound in tropical central Queensland. The IBA includes the marine plain to the east of Broad Sound, which is known locally as Torilla Plain(s), and several, smaller marine plains to the west. The area receives 1000-1400 mm rain annually, experiences a large tidal range (more than 9 m) and incorporates a number of wetland types. Broad Sound is a shallow marine system that includes extensive intertidal flats. Mangrove forest and thickets occur around Broad Sound and are most extensive on the eastern side; there are many mangrove islands. Torilla Plain is a treeless plain marked by interconnected narrow channels and shallow pools separated by low rises; the exceptionally complex networks of this feature may be unique in Australia. In the summer-autumn wet season, the channels and pools can coalesce to form a system of larger marshes and small lakes, and in exceptionally wet years, much of the plain may be engulfed by shallow floodwaters. In the dry season, water may be absent from much of the plain and retained only in larger depressions and deeper channels, or the plain may be almost totally dry. The flats of the western Torilla Plain are dominated by saline tidal creeks and are bare or, more commonly, support salt-tolerant plants. The plain's wetlands are subject to greatest freshwater influence (discharge from a number of freshwater creeks) on the eastern side. Wetlands on central and eastern Torilla Plain are dominated by grasses, sedges, forbs and marginal remnants of paperbark Melaleuca. Wetlands on the western plains are generally similar to Torilla Plain but are discontinuous and mostly more saline. Seawalls, erected to improve grazing pasture by stopping tidal incursion, are widespread on the western side and have created additional, temporary and persistent freshwater/brackish wetlands; railway and road causeways also hold back freshwater and there are a few semi-permanent ponds. However, legislation now prevents new sea walls being built. The IBA is located in close proximity to, but does not abut, the Shoalwater Bay IBA.

Key biodiversity
Surveys of waterbirds in the IBA have recorded 66 species, 21 of them breeding, in the eastern wetlands in 2003 and 88 species, 25 of them breeding, mainly in the western wetlands in 2006-07. A maximum 37,000 waterbirds was documented in the eastern part of the IBA in March 2003. Species recorded in substantial but sub-threshold numbers are Mapgie Goose, Intermediate Egret, Plumed Whistling-Duck, Black Swan, Grey Teal, Brolga, Marsh Sandpiper (1593 birds on western side of Broad Sound in March 2007), Black-winged Stilt (3373 birds), Black-tailed Godwit and White-winged Black Tern. The IBA also supports the largest of three known breeding populations of the nationally Critically Endangered Capricorn subspecies of Yellow Chat. Small numbers (up to tens) of Radjah Shelduck and Cotton Pygmy-goose occur and breed in the IBA; other uncommon species include Great-billed Heron (historical record in EPA WildNet database), Black Bittern, and Australian Little Bittern. Breeding colonies of 500-2000 pairs of egrets (four species) occur in mangrove forest adjacent to marshy feeding areas on both the eastern and western plains (2004, 2007); these are among the very few such colonies known in Central Queensland. Smaller colonies, of ibises and cormorants (in wooded swamps) and Whiskered Terns and Magpie Geese (in grass-sedge swamps), have been found on one or both sides of Broad Sound. Six high-tide roosts of 50-2200 migratory shorebirds on the western side of Broad Sound have been recently documented and larger numbers (up to 7500) of other migratory shorebird species use the site's shallowly-inundated salt pans and small lakes (Australian Wetlands Database 2001; Jaensch et al. 2004a, 2004b; Jaensch et al. 2005; Wetlands International, unpublished data provided by R. Jaensch). Five records of Australian Painted Snipe from 2003 to 2007, including three breeding records, suggest a small breeding population (R. Jaensch in litt. 2008). There has been at least one record of the biome-restricted Yellow Honeyeater at Broad Sound (Atlas of Australian Birds database).

Non-bird biodiversity: The north-western part of Broad Sound is frequented by considerable numbers of Dugong (Australian Wetlands Database 2001). The Dugong is listed as a threatened species in Queensland under the Nature Conservation Act 1992.



Pressure/threats to key biodiversity
Raise awareness of conservation values in local community and encourage inclusion of values in property-level planning. Support/establish catchment-wide strategy for control of priority weeds (notably Olive Hymenachne) with land-holders, shires and regional NRM bodies. Support/establish broad community consultation on management of tide exclusion walls/banks.

Protected areas
See separate section.

Land ownership
Private (freehold/leasehold); state government (including Environmental Protection Agency/Queensland Parks and Wildlife Service).

Site access / Land-owner requests
Very limited access off public roads. Need to discuss with Fitzroy Basin Association (NRM) as they have the contacts and a mandate for engagement.

Acknowledgements
Comments and data received from Wayne Houston and Alastair Melzer (Central Queensland University) and Roger Jaensch (Wetlands International).


Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Broad Sound (Australia). Downloaded from https://datazone.birdlife.org/site/factsheet/broad-sound-iba-australia on 23/11/2024.