Shorebirds face uncertain future
The world’s shorebirds face an uncertain future as sea levels rise and destroy their traditional feeding grounds and hatcheries, according to new research from the University of Queensland (UQ).
UQ scientists predicts that anywhere between 23 to 40 per cent of the birds’ main feeding grounds could be inundated, leading to a 70 per cent decline in their populations.
This places some of the world's shorebirds at greater risk as some areas have already reported population losses of 30-80 per cent.
“Each year, millions of shorebirds stop at coastal wetlands to rest and feed as they migrate from Russia and Alaska to the coasts of Southeast Asia and Australasia,” said UQ’s Dr Richard Fuller.
“We've discovered that some of these wetlands are highly vulnerable to sea level rise and might be lost in the next few decades. If the birds can no longer stop at these areas to ‘refuel', they may not be able to complete the journey to their breeding grounds.”
In many cases, encroaching sea levels are already leading to the destruction of significant areas of wetlands, which birds use as feeding grounds on their long migratory journeys.
Species showing signs of being in trouble include the bar-tailed godwit, curlew sandpiper, eastern curlew, great knot, grey-tailed tattler, lesser sand plover, red knot and terek sandpiper.
The scientists used “graph theory”, a mathematical approach to estimate the impact of the loss of these wetlands on shorebirds.
“We found that if a tidal wetland habitat serves as an important ‘stepping stone' for the shorebirds, a small amount of habitat loss can trigger disproportionally large declines in the population,” says Dr Takuya Iwamura of Stanford University.
Dr Fuller said that huge areas of coastal wetlands have been reclaimed by urbanisation and agriculture, leading to a precipitous loss in bird populations.
While some existing wetlands can shift inland as sea levels rise, sites along highly developed coastlines, for example in Japan, China and the Republic of Korea, cannot move at all because of the scale of human development close to the coast.
“While we can build sea walls to defend ourselves against rising sea levels, the cost of this will only increase as time goes by,” Dr Fuller said. “We could instead be looking for opportunities to return our coastlines to a more natural state.