Extensive searches for the Bramble Cay melomys, a small rat-like animal, have failed to find a single specimen from its only known habitat on a sandy island in far northern Australia Climate change appears to have driven to extinction an Australian Great Barrier Reef rodent, according to a new study, which suggests the species may be the first mammal lost to the global phenomenon. 
 
 Extensive searches for the Bramble Cay melomys, a small rat-like animal, have failed to find a single specimen from its only known habitat on a sandy island in far northern Australia. 
 
 Researchers said the key factor behind the extinction was "almost certainly" ocean inundation of the low-lying cay, likely on several occasions, over the last decade which resulted in dramatic habitat loss. 
 
 Available data on sea-level rise and weather events in the Torres Strait region "point to human-induced climate change being the root cause of the loss of the Bramble Cay melomys", added the Queensland state government and University of Queensland study. 
 
 The Melomys rubicola, considered the Great Barrier Reef's only endemic (found nowhere else) mammal species, was first discovered on the cay in 1845 by Europeans who shot the "large rats" for sport. 
 
 But the last known sighting, by a professional fisherman, was in 2009. 
 
 When a 2014 study found no sign of the species, researchers decided to conduct the most extensive survey possible in the hope of conserving the species. 
 
 That survey—using traps, cameras and searches—"produced no records of the species, confirming that the only known population of this rodent is now extinct", said the report. 
 
 The 2015 IUCN Red List of Threatened Species implicated climate change in the extinction of another mammal, the Little Swan Island hutia (Geocapromys thoracatus), a rodent previously found on a coral atoll in Honduras. 
 
 But it found the main driver of its demise was an introduced cat, the report said. 
 
 "Consequently, the conclusion here that the extirpation of the Bramble Cay melomys from Bramble Cay occurred because of rising sea levels and an increased incidence of extreme weather events over preceding years is significant in that it probably represents the first documented mammalian extinction due solely (or primarily) to anthropogenic climate change," it said. 
 
 The study added that the main hope for the species was that another population existed in neighbouring Papua New Guinea. 
 
 "Consequently, at this stage, it may be premature to declare the Bramble Cay melomys extinct on a global scale," it added. 
 
 Environment group WWF-Australia said the fate of the species was a sad reminder of the nation's extinction crisis. 
 
 "Australia officially has the worst rate of mammal extinction in the world," said spokesperson Darren Grover. 
 
 Unless governments commit significant funding towards protecting Australia's threatened species, "we can expect to see more native critters go extinct on our watch", he added. 
 
 Explore further: Feral cats behind extinction of unique Aussie mammals: study ||||| Bramble Cay melomys 
 
 Common name: Bramble Cay melomys 
 
 Scientific name: Melomys rubicola (Melo = Melanesian, mys = mouse; rubicola = Bramble (Cay) 
 
 Family: Muridae (native rats and mice) 
 
 Conservation status: This species is listed as extinct in the wild in Queensland (Nature Conservation Act 1992) and endangered nationally (Environment Protection and Biodiversity Conservation Act 1999). 
 
 Description 
 
 The Bramble Cay melomys was one of the mosaic-tailed rats (distinguished by the mosaic pattern of scales on its tail rather than the concentric rows of scales running along the length of the tail found in most other types of rats and mice). It was larger than the three other Australian species of melomys and about the size of a small rat (head and body length: 148-165 mm; tail length: 145-185 mm). Also distinguishing it from other Australian melomys was that its tail was obviously lumpy, with each scale on the tail being bulbous. It had reddish-brown fur with a paler underbelly, relatively small ears and a long tail with a prehensile tip. 
 
 Habitat and distribution 
 
 This species was only found on Bramble Cay, a small vegetated coral cay (a reef island composed of coral rubble and sand) roughly 340 m long by 150 m wide, but subject to seasonal changes in both shape and size, located at the northern tip of the Great Barrier Reef. This made it Australia's most isolated species of mammal. There has been speculation that the species may also occur on other islands in the Torres Strait or in Papua New Guinea (PNG), given the close proximity of the cay to the mouth of the Fly River, which regularly deposits large amounts of debris (e.g., logs and assorted driftwood, whole palm trees and other vegetation) on Bramble Cay. Further survey work on these islands and PNG, along with clarification of the taxonomic status of the Bramble Cay melomys in relation to PNG species, is required (Latch 2008). 
 
 Life history and behaviour 
 
 Little was known about the biology and ecology of the Bramble Cay melomys. Individuals had been observed foraging at night among the island’s herbaceous vegetation and were thought to be dependent upon plant material, particularly the succulent herb Portulaca oleracea, for food. It is possible the species also ate turtle eggs. 
 
 Trap data demonstrated that the Bramble Cay melomys had a strong female-biased sex ratio. Pregnant and lactating females, juveniles and subadults had all been trapped in July, suggesting an extended winter breeding season. 
 
 The Bramble Cay melomys coexisted with large numbers of shorebirds (noddies, terns and boobies) and nesting green turtles. The Bramble Cay melomys were noted to avoid areas in which high densities of shorebirds occurred. 
 
 In 1978, the population on Bramble Cay was estimated to comprise at most several hundred individuals. A formal population census of the Bramble Cay melomys conducted in 1998 estimated the cay’s population size was 93, based on the capture of 42 individuals. Surveys conducted for the species in 2002 and 2004 detected only 10 and 12 individuals, respectively. These results suggested there had been an ongoing decline in the abundance of the Bramble Cay melomys. A survey in 2011 and two surveys in 2014 failed to locate the species at all. The most recent of these assessments, conducted in August–September 2014, confirmed that the Bramble Cay melomys has been extirpated from Bramble Cay. 
 
 Searches of other Torres Strait islands have failed to discover another population of the Bramble Cay melomys. 
 
 Threatening processes 
 
 Being confined to a single, very small, isolated location, the species was susceptible to a range of threats. It appeared to be inbred, an intrinsic problem that raised doubts about the long term viability of the population. 
 
 The Bramble Cay melomys was also vulnerable to threats posed by the introduction of weeds, predators and competitors, and novel diseases. Certainly, anecdotal reports indicate at least some individuals were killed by domestic dogs that were released onto the island from visiting boats, but also that the species was hunted by indigenous people who visited from PNG on a sporadic basis. 
 
 Although the cay demonstrates seasonal fluctuations in size (involving periods of erosion or deposition as a result of prevailing winds, waves and tides), phases of significant erosion may have impacted directly on the Bramble Cay melomys by reducing the area available for the species to occupy or limiting the availability of potential daytime refuges in caves and crevices in phosphatic rock outcrops at the south-eastern end of the island. 
 
 Most critically, however, the extent of herbaceous vegetation on Bramble Cay decreased dramatically during the 10-year period following 2004, when the species was last captured. The primary cause of this significant decline in habitat was repeated seawater penetration of the island’s interior, which killed or damaged the vegetation. With an elevation of only 3 m above high tide level, Bramble Cay is particularly vulnerable to ocean inundation. This appears to be the threat that eventually sealed the fate of its resident melomys population. 
 
 Available evidence indicates that the anthropogenic climate change-induced impacts of sea-level rise, coupled with an increased frequency and intensity of weather events that produced damaging storm surges and extreme high water levels, particularly during the last decade, were most likely responsible for the extirpation of the Bramble Cay melomys from Bramble Cay. 
 
 Recovery actions 
 
 Because the Bramble Cay melomys is now confirmed to have been lost from Bramble Cay, no recovery actions for this population can be implemented. 
 
 Nevertheless, surveys for the species in other locations are warranted. It appears unlikely that the species occurs on any other Torres Strait island, but there is a possibility that the species is extant in the Fly River delta of PNG, an area that has received comparatively little mammal survey effort to date. 
 
 Related information 
 
 Dennis, A.J. 2008. Bramble Cay Melomys Melomys rubicola. In The Mammals of Australia, Third Edition (Eds S. Van Dyck & R. Strahan), pp 673–674. New Holland Publishers, Sydney, NSW. 
 
 Dennis, A.J. 2012. Bramble Cay melomys Melomys rubicola. In Queensland’s Threatened Animals. (Eds L.K. Curtis, A.J. Dennis, K.R. McDonald, P.M. Kyne & S.J.S. Debus), pp 398–399. CSIRO Publishing, Collingwood, Vic. 
 
 Gynther, I., Waller, N. & Leung, L.K.-P. (2016) Confirmation of the extinction of the Bramble Cay melomys Melomys rubicola on Bramble Cay, Torres Strait: results and conclusions from a comprehensive survey in August–September 2014. 
 
 Latch P. 2008. Recovery Plan for the Bramble Cay Melomys Melomys rubicola. Report to Department of the Environment, Water, Heritage and the Arts, Canberra. Environmental Protection Agency, Brisbane. 
 
 Limpus, C.J., Parmenter, C.J. & Watts, C.H.S. 1983. Melomys rubicola, an endangered murid rodent endemic to the Great Barrier Reef of Queensland. Australian Mammalogy 6: 77–79. 
 
 Woinarski, J.C.Z., Burbidge, A.A. & Harrison, P.L. 2014. The Action Plan for Australian Mammals 2012. CSIRO Publishing, Collingwood, Vic. 
 
 Waller Natalie L., Gynther Ian C., Freeman Alastair B., Lavery Tyrone H., Leung Luke K.-P. (2017) The Bramble Cay melomys Melomys rubicola (Rodentia: Muridae): a first mammalian extinction caused by human-induced climate change? Wildlife Research 44: 9-21. ||||| For the first time in recorded history, the extinction of a mammalian species has been linked primarily to man-made climate change. 
 
 The Bramble Cay melomys, a small rodent that lived only on an island in the Great Barrier Reef, appears to have been completely wiped out, The Guardian reported. 
 
 The rodent, also called the mosaic-tailed rat, was found on Bramble Cay, a small coral strip near Queensland, Australia. 
 
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 A study led by Ian Gynther from Queensland’s Department of Environment and Heritage Protection, and in partnership with the University of Queensland, laid 150 traps on the island for six nights. It found no evidence of the melomys. 
 
 Its report concludes that the “root cause” of the animal’s decline was rising sea levels on its coral home, which sits very low above the water. The area of the island above high tide fell from 4 hectares in 1998 to 2.5 hectares in 2014, the study found. 
 
 A 2012 University of Queensland study highlighted the impact of climate change on habitat destruction across the world, finding that “serious declines are already a reality for many species.”
– Way to go, humanity. For the first time in history, human-induced climate change has been found "solely or primarily" responsible for the extinction of a mammal species, according to a new study. The Bramble Cay melomys, or mosaic-tailed rat, was found by Europeans on a tiny coral cay off the coast of Queensland, Australia, in 1845 and became known as the only mammal species endemic to the Great Barrier Reef, reports the Guardian. But though there were hundreds still in existence on Bramble Cay in 1978, the last were spotted by a fisherman in 2009, reports AFP. Researchers from the University of Queensland and the Queensland government—who traveled to Bramble Cay in 2014 and laid 150 traps for six nights to no avail—say "the only known population of this rodent is now extinct." Researchers found the cay, which sits about 10 feet above sea level, had flooded several times, wiping out the animals and their habitat. Just 2.5 hectares of land remained above high tide, reports Newsweek. "Significantly, this probably represents the first recorded mammalian extinction due to anthropogenic climate change," the researchers say—though they hope the animals reached the island on debris from Papua New Guinea and still survive there. Researchers say extreme weather was a factor in the extinction of the Little Swan Island hutia, a rodent once found on an atoll off Honduras, but cats were also to blame. "If this is one of the first" extinctions solely linked to humans, "it is more than likely not going to be the last," says an ecologist. "Species restricted to small, low lying islands, or those with very tight environmental requirements are likely to be the first to go." (Five islands have already vanished.)