Thousands of endangered snails raised in captivity returned to natural habitat in Bermuda

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  • Due mostly to predation by invasive species of carnivorous snails and flatworms, greater Bermuda land snails (Poecilozonites bermudensis) were driven nearly to extinction in their native habitat on the oceanic islands of Bermuda over the past several decades. In fact, the snails were believed to have disappeared altogether until 2014, when a small population was discovered.
  • It’s believed that there are less than 200 of the snails remaining in the wild, but that population has now been joined by 4,000 individuals bred in captivity in the UK and reintroduced on Bermuda’s Nonsuch Island — a nature reserve with strict quarantine protocols designed to ensure that alien species detrimental to the snails will not be introduced to the island.
  • Following the 2014 rediscovery of the greater Bermuda land snail, scientists at the UK’s Chester Zoo and the Zoological Society of London launched a collaborative captive breeding program for the snails at the request of the Bermudian government. Over the past three years, the breeding program has built up a population of the snails with sufficient numbers to begin reintroductions in the wild.

Thousands of captive-bred greater Bermuda land snails are heading home.

Due mostly to predation by invasive species of carnivorous snails and flatworms, greater Bermuda land snails (Poecilozonites bermudensis) were driven nearly to extinction in their native habitat on the oceanic islands of Bermuda over the past several decades. In fact, the snails were believed to have disappeared altogether until 2014, when a small population was discovered.

It’s estimated that there are less than 200 of the snails remaining in the wild, but that population has now been joined by 4,000 individuals bred in captivity in the UK and reintroduced on Bermuda’s Nonsuch Island — a nature reserve with strict quarantine protocols designed to ensure that alien species detrimental to the snails will not be introduced to the island.

Following the 2014 rediscovery of the greater Bermuda land snail, scientists at the UK’s Chester Zoo and the Zoological Society of London launched a collaborative captive breeding program for the snails at the request of the Bermudian government. Over the past three years, the breeding program has built up a population of the snails with sufficient numbers to begin reintroductions in the wild.

Thousands of the rare snails have been returned to the wild. Photo courtesy of Chester Zoo.

“It’s incredible to be involved in a project that has prevented the extinction of a species,” Gerardo Garcia, Chester Zoo’s curator for lower vertebrates and invertebrates, said in a statement.

Garcia described the greater Bermuda land snail as “one of Bermuda’s oldest endemic animal inhabitants.” He added that “It has survived radical changes to the landscape and ecology on the remote oceanic islands of Bermuda over a million years but, since the 1950s and 60s, it has declined rapidly. Its demise is mainly due to changes to their habitat and the introduction of several predatory snails. Indeed, in the early 1990s, it was actually believed to be extinct until it was discovered again in one remote location in 2014.”

Mark Outerbridge, a wildlife ecologist with the Bermudian government, joined Chester Zoo zookeeper Heather Prince and snail specialist Kristiina Ovaska in transporting the snails back to Bermuda for release. A select number of the snails were outfitted with fluorescent tags, a technique for tracking the snails that was tested by Ovaska and the team at the Chester Zoo. The tags will allow scientists to observe the snails’ dispersal across Nonsuch Island, as well as their growth rates, activity patterns, and population size — all of which will help monitor the snails’ success at adapting to and, hopefully, proliferating in their new home.

Fluorescent tags will allow scientists to track the reintroduced snails’ progress in adapting to their new life in the wild. Photo courtesy of Chester Zoo.

Further releases of the greater Bermuda snail and the lesser Bermuda snail, another species of land snail that is being bred at the Chester Zoo, are planned in the near future, following work to restore critical habitat on many of Bermuda’s offshore islands.

“It has been tremendously gratifying for me to see [the snails] return to Bermuda for reintroduction,” Outerbridge said in a statement. “We have identified a number of isolated places that are free of their main predators and I am looking forward to watching them proliferate at these release sites.”

Article Source: Mongabay