More than 1,300 tiny, critically endangered snails have been set free to roam on an island off the coast of Morocco after a breeding programme rescued two obscure species from the brink of extinction.
The Desertas Island land snails had not been recorded for more than 100 years and were believed to have disappeared from their natural habitat on the windswept, mountainous island of Deserta Grande, close to Portugal-owned Madeira.
Experts at the Instituto das Florestas e Conservação da Natureza (IFCN) rediscovered minute populations of two species of the snail, each consisting of fewer than 200 survivors, in conservation expeditions between 2012 and 2017 amid fears that invasive predators might have eaten the pea-sized molluscs into oblivion.
The snails were taken to zoos in the UK and France, with 60 flown to Chester zoo, where the conservation science team liaised with experts in Madeira and constructed new homes for them in mini habitat tanks as part of a breeding programme to quickly boost numbers.
Dr Gerardo Garcia, Chester zoo’s head of ectotherms, said the future of the species “was in our hands” when the snails first arrived. “It was a huge responsibility to begin caring for them,” he said. “As a zoo conservation community, we knew nothing about them. They’d never been in human care before and we had to start from a blank piece of paper and try to figure out what makes them tick.”
Garcia said the snails “really were on the edge of extinction” and he paid tribute to his team of zookeepers who “spent countless hours caring for every individual snail”.
The snails have been released into a wild refuge on Bugio, a smaller neighbouring island in the Madeira archipelago that has been off-limits to humans since 1990 to protect its fragile ecosystem, where invasive species like rats, mice and goats have been eradicated.
Heather Prince, an invertebrate specialist at Chester zoo, said: “Within a few months we were able to crack the breeding of the Desertas land snails. Crucially, we were then successful in breeding multiple generations. This was key, because it meant we could then bring in the support of other zoos and establish a network, breeding them in the substantial numbers needed to have a chance of saving the species.”
Each of the snails reintroduced has been individually marked for monitoring. If successful, many more will be released to bolster numbers.
Dinarte Teixeira, a conservation biologist at IFCN, said: “These snails are incredibly precious. The Desertas Islands are the only place in the world where they can be found and so we’re striving to do everything we can to give them the best possible chance for the future. For 100 years we thought they’d gone for ever, but now there’s new hope.”
