The most recent update of the IUCN Red List of Threatened Species has highlighted extinctions of Australian species and upgraded threats related to climate change.
Three reptile species found only on Christmas Island - Whiptail-skink, the Blue-tailed Skink (Cryptoblepharus egeriae) and the Lister’s Gecko – have gone extinct, according to the update.
Overall, populations of Christmas Island reptiles have declined rapidly since the 1970s. While the reason for their decline remains unclear, predation by the invasive Wolf Snake (Lycodon capucinus), introduced to the island in the mid-1980s may be to blame. The introduction of a novel disease and changes in island ecology following the introduction of the Yellow Crazy Ant (Anoplolepis gracilipes) may have placed further pressure on these reptile species. Efforts to establish a captive breeding programme for the Forest Skink failed in 2013 and the species has now been moved from Critically Endangered to Extinct. Although captive breeding populations are now well-established for the Lister’s Gecko and the Blue-tailed Skink, both species have been declared Extinct in the Wild.
The Western Ringtail Possum (Pseudocheirus occidentalis) has moved from Vulnerable to Critically Endangered due to a fall in species numbers by over 80% in the past ten years.
The Possum was once widespread in peppermint (Agonis flexuosa) and tuart (Eucalyptus gomphocephala) forests in Western Australia, but is now limited to fragmented coastal habitats. Attempts to re-establish the species in Lane-Poole Conservation Park, about 100 km south of Perth, have failed largely due to poor food quality resulting from a drying climate. Western Ringtail Possums require relatively high quality food – particularly peppermint leaves – due to their specialised digestive systems.
The Western Ringtail Possum is susceptible to heat stress and can overheat at temperatures above 35ºC, increasingly common in this part of Australia. Possum numbers have also been impacted by urban development and predation from the Red Fox (Vulpes vulpes) and feral cats (Felis catus), logging, fire outbreaks and inappropriate fire management regimes.