Why 1329 tiny snails are released on a remote island

More than 1,300 critically endangered zoo-bred pea-sized snails have been released (very slowly) on a remote Atlantic island.

The release returns two species of Desertos Island land snails to the wild. Before that, they were considered extinct – none of the species had been seen for a century.

When a team of conservationists found a small population surviving on the rocky cliffs of the island of Deserto Grande, near Madeira, they began a rescue operation.

The snails were brought to zoos in Great Britain and France, including Chester Zoo, where a home was created for them in a converted shipping container.

The tiny clams are native to the windward, mountainous island of Deserto Grande, southeast of Madeira. The habitat there has been destroyed by rats, mice and goats brought to the island by humans.

All of these invasive predators were thought to have eaten the tiny snails to extinction. Then a series of conservation expeditions – between 2012 and 2017 – proved otherwise.

Conservationists found only 200 surviving individuals on the island.

These snails were considered the last of their kind, so they were collected and taken into captivity.

A conservation science team has created a new home for 60 precious snails at Chester Zoo. The correct feed, vegetation and conditions were recreated in the miniature habitat tanks.

The 1,329 snail offspring bred at the zoo have now been marked with identification dots – using non-toxic pens and nail polish – and transported back into the wild for release.

“(It’s) a color code,” said Dinarte Teixeira, a conservation biologist at Madeira’s Institute of Nature Conservation and Forestry. “This will allow us to detect them and track where they go, how much they grow, how long they survive and how well they adapt to their new environment.”

A wild refuge has been re-established for snails on Bugia, a smaller neighboring island in the Ilhas Desertas (Desert Islands) archipelago.

Bugio is a nature reserve and invasive species have been eradicated there.

Chester Zoo’s Gerardo Garcia said the reintroduction was “an important step towards the recovery of the species”.

“If all goes as well as we hope, more snails will follow next spring. It’s a huge team effort that shows we can make a difference for a critically endangered species.”

“These snails are an important part of the natural habitat (on the islands they come from),” explained Heather Prince from Chester Zoo. She explained that not only are snails food for other native species, but they also break down organic matter and bring nutrients to the soil.

“They help plants grow. It all depends on the little guys — the insects and snails that are so often overlooked.”