PREVIEW

Thousands of “glow-in-the-dark” snails have been reintroduced to French Polynesia as part of a global conservation programme to rescue the species from the brink of extinction.

More than 7,000 zoo-bred Partula snails – many classified as Extinct in the Wild or Critically Endangered – were released across four islands in the South Pacific, marking the largest reintroduction of the fingernail-sized snails to date.

Paul Pearce-Kelly, Senior Curator of Invertebrates at London Zoo and lead of the international Partula conservation programme, said: “This progress is decades in the making. We are not only celebrating the largest release of Partula snails in history, but also the results of over 30 years of dedicated work by conservation zoos and the French Polynesian government to enable the recovery of these precious snails in the wild.”

Before release, each snail was marked with a tiny dab of white UV-reflective paint on its shell. The paint glows blue under ultraviolet light, allowing conservationists to find and monitor the snails during nocturnal surveys.

During the latest reintroductions, the team made a remarkable discovery: an unmarked juvenile Partula varia, the first wild-born member of this snail species to be seen in over 30 years. The find provides proof that the snails are not only surviving on their native island of Huahine, but also breeding successfully – a major milestone for the long-running conservation effort.

The discovery comes less than a year after another Partula species, Partula tohiveana, was reclassified from Extinct in the Wild to Critically Endangered on the IUCN Red List of Threatened Species. Conservationists have also recorded the first evidence of wild-born Partula tohiveana living outside their original release site on the island of Moorea, suggesting the snails are both thriving and expanding their range.

The reintroduction forms part of an annual release programme coordinated by the Zoological Society of London (ZSL), which has seen nearly 40,000 snails returned to the wild over the past decade.

Eleven species and subspecies of Partula snails, reared at institutions including London and Whipsnade Zoos, Bristol Zoological Society, Marwell Wildlife, the Royal Zoological Society of Scotland and several international partners, were transported more than 15,000 kilometres to reach their tropical island homes.

Fiona Sach, ZSL’s Zoo Conservation Impact Manager, added: “This exciting news demonstrates the power of conservation breeding programmes and carefully planned releases in bringing species back from the edge of extinction. Last year’s downlisting of Partula tohiveana already showed what we can achieve for these species, and we hope that Partula varia and other Partula snails will soon join it as another Extinct-in-the-Wild species successfully thriving in the wild once more.”

Also known as Polynesian tree snails, Partula play a vital role in maintaining the health of their forest ecosystems. By feeding on decaying plant material and fungi, they help prevent disease and recycle nutrients back into the environment.

Wild populations of Partula snails were wiped out in the 1980s and early 1990s following the introduction of the carnivorous rosy wolf snail (Euglandina rosea), which was brought in to control the invasive African giant land snail (Lissachatina fulica). To prevent total extinction, conservationists collected the last surviving individuals of 15 Partula species, beginning an international breeding programme to safeguard and eventually restore them to their native habitats.

Christophe Brocherieux, Environment Project Manager at the Environment Department of French Polynesia, added: “We are truly proud to be able to contribute to this international programme, the results of which are increasingly exciting year after year.”

Visitors to London and Whipsnade Zoos can see Extinct-in-the-Wild Partula snails and learn more about their reintroduction at the Tiny Giants invertebrate house.