Millions of shorebirds and some species could be lost as sea levels rise in coming decades, say 宅男导航 scientists who are working as part of an international environmental team.
The group's world-first research predicts that a loss of 23 to 40 per cent of the birds鈥� main feeding grounds could lead to a 70 per cent decline in their populations.
This places some of the world鈥檚 shorebirds at greater risk as some areas have already reported population losses of 30-80 per cent.
鈥淓ach 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,鈥� said Dr Richard Fuller of the 鈥檚 (NERP) and (宅男导航).
鈥淲e鈥檝e 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 鈥榬efuel鈥�, they may not be able to complete the journey to their breeding grounds.鈥�
The NERP researchers studied wetlands along the shorebirds鈥� migration route across coastal Alaska, Russia, China, North Korea, South Korea, Japan, Philippines, Vietnam, Thailand, Malaysia, Indonesia, Papua New Guinea, Australia and New Zealand.
In many cases rapid coastal development and reclamation are already chewing into the tidal wetlands the birds use as feeding grounds on their long journeys, which sometimes extend halfway round the world.
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 鈥済raph theory鈥�, a mathematical approach to estimate the impact of the loss of these wetlands on shorebirds.
鈥淲e found that if a tidal wetland habitat serves as an important 鈥榮tepping stone鈥� for the shorebirds, a small amount of habitat loss can trigger disproportionally large declines in the population,鈥� says Dr Takuya Iwamura of Stanford University, who conducted the research at NERP.
鈥淭his is because some of these tidal wetlands are 鈥榖ottleneck鈥� sites where the majority of the birds stop to refuel.
鈥淔or example, we discovered that a sea-level rise of 150cm may result in the loss of 35 per cent of coastal wetlands, but it could lead to a 60 per cent decline in curlew sandpipers, eastern curlews and great knots.鈥�
NERP scientists are also embarking on a second international study to identify the best ways to save the disappearing shorebirds. This research is crucial for federal policy because Australia has signed migratory bird agreements with China, Japan and South Korea.
鈥淲e鈥檙e aware that some shorebird species have declined in the past few decades, but we still know very little about all the causes for these declines or the scale of the problem,鈥� said Mr Rob Clemens of NERP and 宅男导航.
鈥淥ur studies attempt to piece together what is happening throughout the entire migration journey of these birds.
鈥淲e can then determine which species should be protected, how best we can monitor the birds, and where and how we should act to save them.
鈥淲hile more knowledge would be useful, it鈥檚 important that we start protecting the birds based on what we already know, such as halting the reclamation of coastal wetlands in the vulnerable regions.鈥�
鲍蚕鈥檚 said huge areas of the world鈥檚 coastal wetlands had been reclaimed for urbanisation and agriculture in recent years, reducing the size of the wetlands available for migratory birds.
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.
鈥淲hile we can build sea walls to defend ourselves against rising sea levels, the cost of this will only increase as time goes by,鈥� Dr Fuller said. 鈥淲e could instead be looking for opportunities to return our coastlines to a more natural state.
鈥淲e must act now to protect these crucial 鈥榮tepping stones鈥� for migratory shorebirds 鈥� if you lose one critical site, you risk losing the entire population of a species that stops there.鈥�
The study by Takuya Iwamura, Hugh P. Possingham, Iadine Chad猫s, Clive Minton, Nicholas J. Murray, Danny I. Rogers, Eric Treml and Richard A. Fuller appears in the latest issue of .
The Australian Government funds the National Environmental Research Program (NERP) to inform evidence-based policy and sustainable management of the Australian environment.
More information:
Mr Rob Clemens, NERP Environmental Decisions Hub and 宅男导航, ph +61 (0)425 805 087
Dr Richard Fuller, NERP Environmental Decisions Hub and 宅男导航, ph +61 (0)458 353 102 (US Pacific Daylight Time); r.fuller@uq.edu.au
Dr Takuya Iwamura, Stanford University, ph +1 415 852 1840 (US Pacific Daylight Time)
Professor Hugh Possingham, NERP Environmental Decisions Hub and 宅男导航, ph +61 (0)434 079 061 (currently at Yale University, US eastern standard time); h.possingham@uq.edu.au
Karen Gillow, Science Communications, NERP Environmental Decisions Hub and 宅男导航, +61 (0)7 3365 2450 or +61 (0) 402 674 409 or k.gillow@uq.edu.au
Fiona Cameron, 宅男导航 Communications, +61 (0)7 3346 7086 f.cameron2@uq.edu.au
