May 6, 2013
Shorebirds Could Be Displaced Due To Rising Sea Levels
Brett Smith for redOrbit.com - Your Universe Online
As climate scientists continue to sound warnings about how the impending sea level rise will impact coastal cities, a group of Australian researchers has found that shorebirds could be feeling squeezed even more than humans.
According to the research team´s report in the Proceedings of The Royal Society B (RSPB), a 23 to 40 percent loss of shorebirds´ main feeding grounds could lead to a 70 percent decline in their population.
“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 Richard Fuller of the National Environmental Research Program´s (NERP) Environmental Decisions Hub and The University of Queensland (UQ).
“We´ve discovered that some of these wetlands are highly vulnerable to sea level rise and might be lost in the next few decades,” he said in a statement. “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.”
According to the scientists, species like the bar-tailed godwit, lesser sand plover, curlew sandpiper and terek sandpiper are already being impacted.
To reach their conclusion, the scientists used a mathematical approach known as a “graph theory” to estimate how wetland loss will impact 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,” said co-author Takuya Iwamura of Stanford University. “This is because some of these tidal wetlands are ℠bottleneck´ sites where the majority of the birds stop to refuel.”
“For example, we discovered that a sea level rise of [59 inches] may result in the loss of 35 percent of coastal wetlands, but it could lead to a 60 per cent decline in curlew sandpipers, eastern curlews and great knots,” he explained.
As sea levels rise some wetlands are expected to shift inland; however, in developed coastal areas the wetland shift will not be possible because of human development, the researchers said.
“While we can build sea walls to defend ourselves against rising sea levels, the cost of this will only increase as time goes by,” Fuller said. “We could instead be looking for opportunities to return our coastlines to a more natural state."
“We must act now to protect these crucial ℠stepping stones´ for migratory shorebirds — if you lose one critical site, you risk losing the entire population of a species that stops there,” he added.
The NERP research team is currently involved in a study aimed to identify the best ways to save the birds. The researchers expect that that their results will be part of policymakers´ discussions on environmental policy in their region of the Pacific.
“We´re 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,” said Rob Clemens of NERP and the University of Queensland.