• Alex Taylor

So Long, and Sorry for all the Water...

The Bramble Cay melomys may be unknown to most people, but it has achieved fame by becoming the first mammal declared extinct due to human-induced climate change.

Farewell, Bramble Cay melomys

You have probably never heard of the Bramble Cay melomys. Why would you, it was a tiny mouse-like rodent that lived on a tiny island in the eastern Torres Strait of the Great Barrier Reef. You’ll notice I’m using the past tense – that’s because it has become a famous name in conservation circles, with the sad title of being the first mammalian victim of human-induced climate change. Just last month, the Australian government confirmed its extinction.

The history of this little rodent is a sad tale, with an ending that should ring some alarm bells and teach us all a lesson. It was first seen by European eyes in 1845, and still numbered in the hundreds as recently as 1978. But since 1998, the part of its home island that sits above the high tide mark has shrunk from 4 hectares to 2.5 hectares in 2014. The Bramble Cay melomys ate just a few plant species, so this rising water level meant a 97% loss of its habitat in just 10 years. This, combined with an increase in storm surges, killed off their food source, and the extreme weather likely caused some individuals to be swept off to sea and drowned.

Short surveys in 2011 and early 2014 failed to find any of the rodents. In fact, it hadn’t been seen by humans since a fisherman who had visited Bramble Cay every year for the past ten years spotted one in 2009. This was enough to prompt the scientists to spend five months obtaining permission from the Australian government and various stakeholders to begin a captive breeding programme. They planned to take the last few individuals as an “emergency insurance measure.” But alas, when they returned, they discovered they were too late. Between August and September 2014, their survey involved 900 small mammal trapping-nights, 60 camera traps and two hours of active daytime searches but produced absolutely no records of the rodent. Because it is endemic to that one island, so found nowhere else in the world, the scientists concluded that the species had gone extinct.

The root cause, they said, was sea-level rise caused by climate change, caused by us. The Torres Strait sea level appears to have risen at almost twice the global average between 1993 and 2014. And it seems that climate change is happening faster than scientists are anticipating. The tale of the Bramble Cay melomys shows that we must move faster, we can’t wait. This species may have gone unnoticed in life, an animal isolated from its nearest relative for nearly a million years, and the Great Barrier Reef’s only endemic mammal. But in death we must remember its name and remember the warnings its extinction brings. And it really is gone for good – tissue samples taken from 42 individuals in 1998 have been lost, so we don’t even have a record of its genetic information.

The last Bramble Cay melomys may have starved or drowned at sea, perhaps watched by the seabirds or sea turtles that it shared the island with. Now, their rookeries and nesting beaches respectively are under threat, as are many other species around the world who feel the impacts of climate change. Our actions have consequences, and those consequences are being felt right now.

#climatechange #extinction #sealevelrise #australia

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