First mammal species recognized as extinct due to climate change

The animal seems to have disappeared from
its home in the eastern Torres Strait of the Great
Barrier Reef^[1], scientists say. The
animal was last seen by a fisherman in 2009, but failed attempts to
trap any in late 2014 prompted scientists to say it is likely
extinct.

Also called the mosaic-tailed rat, the
rodent is named after its home on Bramble Cay, a small island that
is at most 10 feet above sea level.

The rats were first seen by Europeans on the island in 1845, and
there were several hundred there as of 1978. But since 1998, the
part of the island that sits above high tide has shrunk from 9.8
acres to 6.2 acres. That means the island’s vegetation has been
shrinking, and the rodents have lost about 97 percent of their
habitat.

“The key factor responsible for the extirpation of this
population was almost certainly ocean inundation of the low-lying
cay, very likely on multiple occasions, during the last decade,
causing dramatic habitat loss and perhaps also direct mortality of
individuals,” writes the team, led by Ian Gynther from Queensland’s
Department of Environment and Heritage Protection.

“For low-lying islands like Bramble Cay, the destructive effects
of extreme water levels resulting from severe meteorological events
are compounded by the impacts from anthropogenic climate
change-driven sea-level rise,” the authors add.

Around the world, sea level has risen by almost eight inches
between 1901 and 2010, a rate unparalleled in the last 6,000 years.
And around the Torres Strait, sea level has risen at almost twice
the global average rate between 1993 and 2014. (Learn
more about rising seas^[2].)

This small mammal is therefore only the first of many species
that face significant risk due to a warming climate, the authors
warn.

“We knew something had to be first, but this is still stunning
news,” says Lee
Hannah,^[3] a senior scientist for
climate change biology with Conservation International.

Hannah has published work suggesting that one in five species
may be at risk from climate change. Those on small islands and
mountains are most threatened, since they have few places to go
when things change, he notes.

“Certainly some species will benefit from climate change, but
most will see reduced ranges,” adds Hannah.

Still, people can work to mitigate the worst impacts, he says,
by designing protected areas that can accomodate changing climate,
by relocating wildlife as needed, and by reducing greenhouse gas
emissions.

“This species could have been saved,” he says.