Nature
PUBLISHED
A small newt just got a big population boost in northern Spain where conservation experts have released 32 captive-bred individuals into the wild. Thought to be down to their last 1,000, things were looking bleak for the Montseny brook newt.
Now, thanks to an international conservation effort, their future just got a little brighter.
Big moves for little newts
Until 2017, the Montseny brook newt (Calotriton arnoldi arnoldi) had never strayed outside of its native home in the Catalonian massifs of Spain. Then, they went airborne.
At the request of the local government, 24 individuals made the journey to Chester Zoo in the UK as part of an ambitious conservation effort to boost their numbers. I say ambitious, because it’s not easy figuring out how to help a rare newt make babies – let alone keeping track of their eggs.
“The females evolved to lay eggs in fast-running water, so they are experts at putting them in tiny hidden crevices – it’s not always easy to find them,” said Ellie Bland, the zoo’s Ectotherms Keeper, who oversees daily water checks, tank cleaning, headcounts, and egg checks, in a statement sent to IFLScience.
Fortunately, they make for entertaining lab mates.
“They’re quite quirky. They are visual hunters that target aquatic worms and insects – I pipette feed them and they are very reactive to movement – so we have these huge eyes watching us while we work.”
Swerving genetic bottlenecks
The breeding program has successfully established 12 breeding pairs that will remain at Chester Zoo. Meanwhile, 32 individuals have been released into a top-secret location within a mountainous habitat near Barcelona, Spain.
Though their numbers have dipped to around 1,000 in the wild, conservationists were encouraged to find that they have maintained reasonable genetic diversity. It’s a long road ahead with habitat disturbance, fungal pathogens, and the pet trade posing significant threats, but hundreds more are expected to follow this initial return to the wild.
“These newts are fascinating, and also quite cute,” said Dr Gerardo Garcia, Animal & Plant Director at Chester Zoo, who has been involved with the Government of Catalonia’s Montseny Brook Newt Recovery Plan since its beginning.
“But they are extremely vulnerable. Their habitat is fragmented by roads, they are highly sensitive to water quality, and they face the constant threat of illegal wildlife trade."
“Usually when numbers get this low, you'd expect genetic diversity to plummet. But research shows it's surprisingly good. That gave us a strong foundation for the project.”
Montseny brook newts gone wild
Tiny UV markers will enable the newts’ progress to be monitored, but there’s still much we don’t know about the secret lives of these elusive amphibians.
As larvae, they’re easy enough to find in the wild, but then they seem to disappear only to reemerge as adults. Conservationists suspect they may sneak off to an underground river system beneath the Montseny mountains.
A mystery we’ve yet to solve, but for the teams in the UK and Spain, getting to see the release of the captive-bred newts was reward enough.
“It’s awesome seeing them swim free,” said Bland. “Moments like this are why I wanted to work in a zoo in the first place.”
