Mammals
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Small mammal extinction risk worsens following new IUCN Red List assessments
Monday 11 November 2024
The risk of extinction has increased for several small mammal species following an update by the IUCN Red List of Threatened Species.
The update included reassessments for nearly 200 small mammal species worked on by the Small Mammal Specialist Group (SMSG), including Dr Ros Kennerley and Dr Abi Gazzard from Durrell, alongside species experts and those working in the species' countries of origin. The SMSG is a global network of scientists and conservationists working to enable a better scientific understanding of over 3,200 species of small mammals and to promote the conservation of the most threatened.
Negative changes in Red List category following assessment are known as 'uplistings', which means the species is creeping closer to extinction and conservation action is more urgent. Category 'uplistings' since the last species assessment show how quickly some populations can decline in less than a decade, emphasising the importance of these reassessments.
For species that have been evaluated and have enough data to be assessed, the categories are Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct.
Notable 'uplistings' for small mammal species following the latest Red List update:
Admiralty Rat
Previous category: Data Deficient
Now: Critically Endangered (Possibly Extinct)
Found solely on Manus Island in northern Papua New Guinea, the Admiralty rat was only formally described in 2016 when photographed using a camera trap. Significant surveys undertaken in 2021 failed to record any further evidence of its presence.
Applying the IUCN's recommended extinction assessment framework, the SMSG estimates that there is a 76% chance that the species is extinct. The Admiralty rat now joins 15 other rodent species that are already listed as Possibly Extinct.
Bahaman Hutia
Previous category: Vulnerable (assessed in 2020)
Now: Critically Endangered
The Bahamian hutia population is severely fragmented after losing much of its historic range in the Bahamas due to hunting, predation by dogs and possibly cats, and competition with other invasive mammals. It is only found in a few locations on three small islands, where the populations are vulnerable to threats such as the introduction of predators, hurricanes and storm surges.
Photo by Mark Erdos
Heath Mouse
Previous category: Near Threatened (assessed in 2016)
Now: Endangered
The Heath Mouse is found in parts of South and Western Australia, where lack of success in targeted surveying has raised cause for concern. It's thought that climate change, wildfires, habitat loss and degradation, and being preyed on by cats and foxes have been driving a decline in numbers.
Photo by David Paul / Museums Victoria
Seram Orange Melomys
Previous category: Data Deficient
Now: Vulnerable
Previously unrecorded since 1920, this species was recently documented as surviving on the island of Seram, Indonesia, in research led by SMSG Deputy Chair for Conservation Actions, Prof. Sam Turvey. Whilst this "rediscovery" is incredibly promising for the species, its recent Red List assessment highlights that action must be taken to continue survey work. It has been listed as Vulnerable due to its small range and because its lowland forest habitat is threatened by commercial logging and clearance for agriculture and plantations.
Western European Hedgehog
Previous category: Least Concern (assessed in 2016)
Now: Near Threatened
A recognisable and widely loved small mammal, the Western European hedgehog faces many threats. Roads, agricultural intensification, and urban growth have likely affected populations. Evidence indicates local and national declines, with some areas losing over 30% of hedgehogs in a decade.
Photo by Piotr Laskawski