Researchers looking into the declining number of long-distance shorebirds say, while there is clear evidence that changes in Australian populations are strongly influenced by factors outside of the country, there may also be losses due to habitat pressure in the Kimberley.
A shorebird monitoring project, supported by the Western Australian Marine Science Institution, found some evidence suggesting that local habitat preferences of shorebirds in northwestern Australia have changed in response to human disturbance of roost sites, mangrove incursion on some beaches in northern Roebuck Bay.
The study, led by Danny Rogers and Chris Hassell from the Australasian Wader Studies Group, focussed on the coastlines of Roebuck Bay and Eighty Mile Beach.
Organic pollution of groundwater from Broome has contributed to algae blooms in Roebuck Bay, which may have detrimental effects on the food available to shorebirds.
“It is not yet clear whether these problems have only resulted in local relocation of shorebirds, or whether it affects their survival rates and population counts,” Danny Rogers said.
|Bottom row: Greater Sand Plovers (Charadrius leschenualtii),
Top row (one mostly hidden): Great Knot (Calidris tenuirostris)
At right centre: Red Knot (Calidris canutus)
(Image: Danny Rogers )
Shorebirds carry out long-distance annual migrations between their feeding grounds in the arctic and non-breeding grounds in the southern hemisphere.
During their non-breeding season, migratory shorebirds are broadly distributed along those parts of the northern Western Australian coast with extensive tidal flats. Especially large concentrations are in Roebuck Bay and the northern 80 kilometres of Eighty Mile Beach.
Of the 41 shorebird species occurring regularly along this coastline, 18 species occur in internationally significant numbers (>1% of the population in the East Asian – Australasian Flyway). In total, more than 635,000 migratory shorebirds depend on the tidal flats of the northwestern Australian coast.
“Given the strong external influences on shorebird numbers in Australia, it is clear that Australian-based monitoring serves an important purpose as a barometer of shorebird populations throughout the East Asian – Australasian Flyway,” Danny Rogers said. “As the most important non-breeding region for shorebirds in Australia, Kimberley coastline monitoring is a very important part of this monitoring effort.”
WAMSI Project Page: www.wamsi.org.au/pressures-migratory-shorebirds
The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.