Chester Zoo

Redefining a snail’s pace: reintroduction and rapid recovery of two Critically Endangered land snails from Bermuda

Chester Zoo - 7th Jul, 2023


The genus Poecilozonites forms an endemic radiation of land snails unique to Bermuda. Of the 12 species known from the fossil record, 2 were known to have survived into the late 20th century, with one of these, P. bermudensis, believed to have become extinct in the 1990s. The main drivers of these species’ declines and extinctions were habitat loss and invasive predators, particularly predatory snails and flatworms.

After the remarkable rediscovery of P. bermudensis in 2014, Chester Zoo received of populations of both species (P. bermudensis and P. circumfirmatus), providing an opportunity to reverse their fates through captive breeding and reintroduction to predator-free locations in Bermuda. The species arrived at the Zoo in 2016 (P. bermudensis) and 2017 (P. circumfirmatus) and the first releases back into the wild were in 2019 (P.bermudensis) and 2020 (P. circumfirmatus).

Captive breeding and reintroduction efforts for P. bermudensis have been hugely successful, despite the challenges posed by COVID-19, with over 111,000 snails being released so far, at 29 locations. Our in-situ partners have carried out crucial translocation, monitoring and restoration to help the remaining wild and reintroduced populations, which has proven highly effective. Subsequent surveying has revealed breeding populations established at several sites. Next steps include the upscaling of efforts with P. circumfirmatus in order to match the success of P. bermudensis.

This project won a Gold in the 2023 BIAZA Awards Field Conservation Category

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