Norfolk Island 2021 Land Snails Set of 2 Stamps MUH
Issue date: 22 June 2021
Norfolk Island, despite an area of just 35 square kilometres, has a high diversity of endemic land snails, when compared to other small islands. There are around 70 described species, although it is thought that this number may have been overestimated and that the true number of unique species is probably closer to 60. Land clearing, combined with the introduction of Polynesian Rats around 1,000 years ago, and Black Rats during the middle of the 20th century, as well as predation by mice and chickens, has likely reduced the number of surviving species to around 50, with five species considered critically endangered.
The endemic land snails of Norfolk Island range in shell diameter from just one millimetre to 22 millimetres, across a wide range of shell shapes. While most species were once widespread across the island, many are now mostly restricted to Norfolk Island National Park, the only area of remnant subtropical rainforest on the island.
In 2020, scientists from the Australian Museum surveyed land snails on Norfolk Island for the first time in almost 20 years , discovering a population of Advena campbelli, a species that is currently listed as Extinct on the IUCN Red List and as Critically Endangered by the Australian Government. The museum has also, this year, commenced a captive breeding program involving some Norfolk Island land snail species, in conjunction with Taronga Zoo, Parks Australia and the Norfolk Island Regional Council.