The North of England Zoological Society – Annual Report and Financial Statements 2021
CASE STUDY – BID TO RESCUE MADEIRA’S LOST SNAILS This year has seen Chester Zoo make a major contribution to preventing the extinction of a number of snails endemic to islands around Madeira. Madeira, an autonomous region of Portugal, is an archipelago of islands in the Atlantic Ocean about 320 miles off the coast of Morocco. This isolation, just like its distant neighbour the Canary Islands, has resulted in the evolution of many unique endemic species. Among these are a number of snails that are found nowhere else on Earth, and have been driven right to the edge of extinction by loss of habitat and invasive species colonising the isolated islands. Chester Zoo has been tackling similar challenges with the species of Bermuda for a number of years, and it was this experience and proven results that resulted in a contact to request our assistance with saving the snails of Madeira. Initially we have set a target to work with five of these species that are right on the edge of extinction, with goals to both start the species’ preservation programmes to breed the snails in captivity and then population restoration programmes to increase the numbers and range of the five snails in the wild.
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In summer 2021, we began by receiving snails of two different species collected from Desertas Grande Island (one of the Madeiran islands) – 36 Discula lyelliana and 81 Geomitra grabhami snails arrived at the zoo from the Madeiran government. Both species are critically endangered, with Discula lyelliana even feared to already be extinct prior to the collection of the snails, and the best estimates for Geomitra grabhami assessing the population as fewer than 500 snails are left. Receiving such precious species, it was our immediate action to divide the populations of both species between ourselves and the care of colleagues at Bristol Zoo – a safeguard just in case unforeseen events occurred. From these starting populations at Chester Zoo of just 18 and 42 snails respectively, our teams immediately set about trying to replicate the wild microhabitat of the snails and provide all the necessary resources and conditions for them to thrive – the first time these species have ever been kept out of their natural environment. Seven months later, under the care and expertise of our invertebrate keepers, we now hold populations of 2,362
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