SYDNEY, Australia — Australian researchers say rising sea levels have wiped out a rodent that lived on a tiny outcrop in the Great Barrier Reef, in what they say is the first documented extinction of a mammal species due to human-caused climate change.

The rodent was known to have lived only on Bramble Cay, a minuscule atoll in the northeast Torres Strait, between the Cape York Peninsula in the Australian state of Queensland and the southern shores of Papua New Guinea. The long-tailed, whiskered creature, called the Bramble Cay melomys, was considered the only mammal endemic to the Great Barrier Reef.

“The key factor responsible for the death of the Bramble Cay melomys is almost certainly high tides and surging seawater, which has traveled inland across the island,” Luke Leung, a scientist from the University of Queensland who was an author of a report on the species’ apparent disappearance, said by telephone. “The seawater has destroyed the animal’s habitat and food source.”

“This is the first documented extinction of a mammal because of climate change,” he said.

Anthony D. Barnosky, a professor at the University of California, Berkeley, who is a leading expert on climate change’s effects on the natural world, called the disappearance of the melomys “a cogent example of how climate change provides the coup de grâce to already critically endangered species.”