Science and conservation for the world’s 2800 small mammal species

IUCN Red List update for the SMSG

redlist_logoThe first set of small mammal reassessments for 2016 are now available on the IUCN Red List of Threatened Species. The regular reassessment of species is crucial to our understanding of how the world’s wildlife is changing, and for catalysing conservation action.

From the 1094 SMSG species recently reassessed, there have been eight genuine changes to status and these all come from the Old World.

Interesting, all except one of the genuine changes are species which occur in Oceania. The differing fortunes of two Australian species are reported here:

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 Bramble Cay Melomys (Melomys rubicola)

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Most of us had probably never heard of the Bramble Cay Melomys. This humble rodent has now gained international recognition as the first mammal likely to have been wiped out by human-induced climate change. It was the only mammal species endemic to Australia’s Great Barrier Reef and resident on one tiny island with an area of just 5 ha. After sightings became increasingly rare, scientists set out to capture any remaining individuals and start a captive breeding program.

Bramble Cay in 2011 - photo by Natalie Waller

The rescue mission to such a remote location required significant planning and upon reaching the island five months later the team found no trace of the species despite targeted surveying. Dr Ian Gynther, Senior Conservation Officer, Queensland Government Department of Environment and Heritage Protection, who led the Bramble Cay Melomys survey explains that

“By the time it was apparent that a captive breeding program was required as an urgent conservation action, it was already too late”

This example provides the SMSG with a timely reminder about the urgency to have a captive breeding strategy in place for species within the group. This is something we would like to have in place in 2017. The first stage will be to take stock of the current situation to identify the species which are already in captivity and the purpose they fulfill within the collections. The second phase will then be to conduct a systematic needs assessment for ex-situ and in-situ captive breeding for SMSG species using a series of questions and criteria to identify goals, threats, and conservation options. Ideally this will be done through several workshops, bringing together experts from the captive breeding community and species conservation experts, with the aim of identifying species at most risk in the wild in need of immediate rescue to avoid extinction.

Within the captive breeding strategy the threat of climate change will need to be considered. Dr Gynther makes the important point that

“[The extinction of the Bramble Cay Melomys] highlights that conservation recovery actions need to be highly responsive, especially where climate change impacts are involved”

 

The Bramble Cay Melomys has now been reclassified from Critically Endangered to Extinct, because severe storms and rising sea level had caused dramatic habitat loss, making the Cay uninhabitable. It was just one of the 437 species within the SMSG considered to be threatened in the 2008 assessments and it now serves as a wake up call for recognising those that require urgent conservation action.

To read the full Red List assessment for this species visit here.

It’s not all bad news for SMSG species in Australia, as there has been an improvement in status for this species:

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Greater Stick-nest Rat (Leporillus conditor)

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The Greater Stick-nest Rat has also been reclassified this year, but to a less threatened category. Once found across much of southern Australia, this nest-building rodent was driven to extinction on the mainland by predation from foxes and cats as well as habitat loss from grazing livestock. Survivors remained on two small islands off the south coast and these became the focus of a species recovery plan.

A Greater Stick-nest Rat Leporillus conditor feeds on native vegetation in the predator proof enclosure on Mount Gibson Wildlife Sanctuary, Western Australia, an Australian Wildlife Conservancy project to help save the threatened species.

A combined effort between zoos, conservation organisations and local government has seen captive bred individuals successfully introduced to several islands and mainland reserves. Numbers are on the rise and the Greater Stick-nest Rat has now been moved from Vulnerable to Near Threatened. This success is testimony to the role conservation intervention can play in saving species from extinction. The species smaller relative, the Lesser Stick-nest Rat (Leporillus apicalis), is already extinct in Australia making the Greater Stick-nest Rat the last of its kind and a truly unique rodent.

Dr John Kanowski, National Science and Conservation Manager at the Australian Wildlife Conservancy (AWC) tells us that

“The improved conservation status of the Greater Stick-nest Rat is due largely to its reintroduction to islands and fenced ‘mainland islands’ that are free of feral cats and foxes. AWC is a leading proponent of reintroductions of threatened mammals to feral predator free areas, with projects at four ‘mainland islands’ and one feral predator free island, and another three projects in advanced stages of planning. The Greater Stick-nest Rat has been reintroduced to a 7832 ha feral predator free area on AWC’s Mt Gibson wildlife sanctuary, the second largest feral predator free area on the Australian mainland, and additional translocations are planned to help bolster the existing population”

To read the full Red List assessment for this species visit here.

 


The IUCN Red List of Threatened Species has provided the most comprehensive inventory of the world’s wildlife and its status for over 50 years, and is an essential tool for prioritising conservation effort. This year’s small mammal reassessments have rigorously evaluated the latest research and risks facing each species, identifying winners and losers as well as those we still know so little about. To find out more about IUCN Red List categories and criteria visit here.


 

Article written by Rachael Gerrie and Ros Kennerley. Many thanks to those who provided photographs and quotes.