After hours of setting and checking traps and infrared camera images, a team of Australian biologists has declared the Bramble Cay melomys extinct thanks to climate change. The small brown rodent was last seen on a tiny island off the coast of Papua New Guinea by a fisherman in 2009 and scientists have been unable to find any trace of it since. Signs of flooding suggest rising sea levels are to blame.
“This is the first documented extinction of a mammal because of climate change,” Luke Leung, a biologist from the University of Queensland involved in the research, told the New York Times.
The Bramble Cay melomys population hovered around several hundred in the 1970s. A census of the island turned up a mere 12 individuals, while a 2011 census proved fruitless. The small island has dramatically changed shape and size over the years, and flooding from storm surges has left very little habitat for the non-amphibious creatures.
Leung and a team of researchers visited Bramble Cay in 2014 and instead of rodents found sparse vegetation, a troubling sign for a species that has relied on the vegetation as a source of food and shelter. They also found plenty of washed up logs, an indication the island had recently been flooded.
“It’s exactly the type of species that we could expect to be impacted by climate change,” says H. Resit Akçakaya, a biologist at Stony Brook University. His research focuses on methods of predicting the vulnerability of species in relation to climate change.
The melomys is the first clear case of a mammal’s extinction resulting from climate change, but there are species that have likely gone extinct without scientists even knowing they existed in the first place, Akçakaya says. While it can be hard for biologists to determine exactly why a species dies out, he says it’s “much cheaper and more effective” to try to save a species early on, especially when the suspected cause is climate change. “I don’t think we should wait to emphasize these issues until a species goes extinct,” he says.
Other species that live on Bramble Cay, including birds and sea turtles, are threatened by effects from climate change, too. Ian Gynther, who worked on the research team with Leung on behalf of Queensland’s Department of Environment and Heritage Protection, says that as sea levels rise and storms become more frequent and more intense, “the impacts from ocean inundation are likely to increase.”