Sask. researcher says discovery will help protect colorful, poison frogs - via Herp Digest

Andrés Posso-Terranova studies poison frogs in the Colombian jungle

Alicia Bridges CBC News · 2/21/20

A Saskatchewan-based researcher who left the ice-cold Prairies for humid Colombian jungles in search of vividly hued harlequin frogs says his latest discovery about the endangered amphibians gives them a better chance at survival. 

In 2018, University of Saskatchewan biologist Andrés Posso-Terranova described three new species of harlequin poison frogs that were previously classified as a single species. One of them, Oophaga andresi, is named after him.

Now Posso-Terranova has discovered that hybrid frogs, which show mixes of colour and pattern from different species, exist due to naturally occurring interbreeding.

Originally it was thought the hybrids might be the result of human interference linked to trafficking of the frogs on the international black market.

Posso-Terranova had heard from people in Colombia that some frogs had been moved from deep in the jungle to areas closer to homes for easy access to sell to traffickers. 

"We performed genomics analysis and then we discovered that these individuals are … not recent hybrids," he said, adding that this finding suggests they hybridized naturally, because it occurred more than 20 years ago. 

The study, which was recently published in the journal Molecular Ecology, shows the hybrid frogs are the result of interbreeding between the Oophaga anchicayensis and the critically endangered Oophaga lehmanni. 

Posso-Terranova said the hybrid may eventually be defined as its own species, depending on further genetic analysis.  

For now, he said, the discovery helps illustrate that the hybrids should be protected and allays any concerns that they could pose a genetic threat to existing "pure" species.

He said identifying and naming individual poison frog species is key to their survival long-term. 

Posso-Terranova started researching the genetic diversity of the poison frogs because, having grown up near the Chocó tropical rainforest, he saw how quickly their populations were dwindling. 

One researcher had previously classified the harlequin frogs, known to scientists as Oophaga histrionica, as being one species in research dating back to 1967. 

But there was a huge amount of diversity in the splashes of colour and patterns displayed by the frogs as a warning to predators. 

"If you propose that you have a particular group of frogs that are all over the place and it's only one species you may think, 'Oh, this is very common," he said. 

After discovering the new species in 2018, Posso-Terranova decided to focus his research on the hybrids.

He said these types of discoveries are needed to promote conservation because threats to the endangered harlequin frogs are serious and wide-ranging. 

He said wildlife traffickers exploit impoverished Colombian people by paying them a few Canadian dollars to collect hundreds of poison frogs, which can fetch prices of up to $2,000 on the international black market. 

Posso-Terranova said government conservation policies alone cannot protect the frogs. 

"I completely believe that in order to conserve this species you have to have the participation of the people living there," he said. 

Columbian universities are now providing funding for local people to develop ecotourism as an alternative source of income that discourages illegal trafficking, he added.

There are also efforts to encourage the government to purchase land where there is important frog habitat

As a specialist in genetics, Posso-Terranova brings his knowledge and experience back to Saskatchewan to share with students in Saskatoon. 

He is an instructor and lab co-ordinator at the University of Saskatchewan, where his desk is surrounded by toy frogs and frog paintings drawn by school children he has presented to. 

Posso-Terranova said hiking the Colombian jungles for the vulnerable creatures can be draining — until he finds them. 

"When you find the frogs, when you work for them, when you realize you are doing something good for them, you feel good," he said.

Frogs Tote Tiny Radios to Save Their Species – via Herp Digest

Scientists recently released hundreds of harlequin frogs to learn more about a deadly fungus pushing the species to extinction.

By Sarah Gibbons National Geographic January18, 2018

Hundreds of colorful frogs, barely the size of a palm, have been released into the wilds of Panama in the hopes of reviving a critically endangered species.

The variable harlequin frogs, raised in captivity at a Smithsonian's Conservation Biology Institute facility in Panama are part of an experiment to see how the amphibians will fare in a country besieged by a pervasive and deadly disease. The population has declined by more than 80 percent over the last three generations, and in Panama, wild populations exist only in some protected areas.

The scientists gave 500 frogs a unique marking visible under UV light, while 30 additional frogs were released wearing miniature radio transmitters, says Brian Gratwicke, international coordinator for the Smithsonian's Panama Amphibian Rescue and Conservation project and a National Geographic Explorer.

The Smithsonian team staged a similar release with another species of harlequin frog last June. Here, one wears a small radio transmitter. Because of heavy rains, the research team was unable to take photographs of the radio-wearing frogs from this recent release. 

PHOTOGRAPH BY ROSHAN PATEL

Over the next few months, scientists will watch closely to see where the black-and-yellow splotched frogs go—and if they survive.

While the amphibians face some threats from habitat loss and the illegal trade, by far their biggest threat is chytrid fungus, which has destroyed many of Central America's frog populations.

HOW THE FUNGUS SPREAD

Found throughout Panama since the 1990s, the fungus feeds on live vertebrates and causes a disease in amphibians called chytridiomycosis. Scientists believe it primarily affects frogs' skin, which is how they breathe and take in water. (See 13 Gorgeous Pictures Remind Us Why Frogs Need Our Help.")

In captivity, the disease can be treated with antifungal medication, but "it's been causing devastating effects for New World frog populations," says Gratwicke.

In Panama, the fungus caused a massive frog population die-off and is thought to be responsible for the extinction of the golden toad.

According to Gratwicke, scientists believe trade may have facilitated the spread of chytrid. It's thought to have originated in Mexico in the 1970s before it trickled south to Costa Rica in the 1980s. (Read about vanishing amphibians in National Geographic magazine.)

Jonathan Kolby, a National Geographic Explorer who studies how chytrid impacts frogs in Honduras, notes that the fungus occurs naturally, but during the mid 20th century, two different strains mutated.

"What seems to have forced that change is human activity. Two strains were brought together and created the global pathogenic strain," he says.

By the time scientists identified the strain it was too late for much of the infected regions. Once chytrid is introduced in an environment, it can't be removed without also harming frog populations.

SEARCHING FOR SAFE HAVENS

Gratwicke and his team hope that by tracking where the newly released frogs disperse, they can determine where amphibians are more susceptible to chytrid. The fungus is known to thrive in cold, moist environments. (Read "The Search for Missing Frogs Brings Some Species Back From the Dead.")

"The area where we're conducting the release is a lowland area, and there have been some hypotheses that perhaps if you release frogs in warmer areas, it might act as a climactic barrier" against the disease, says Gratwicke.

"If we do collect enough data," Gratwicke adds, "that would enable us to map refuges."

Kolby is less hopeful that such regions exist: "I'm not optimistic that there are clearly defined natural areas to evade chytrid.”

ALTERNATIVE METHODS

Instead, he's looking at how scientists can manipulate environments to prevent chytrid from growing. Acidity, for example, is thought to slow down chytrid, and some aquatic environments can be made more or less acidic based on the level of vegetation.

In rare cases, some harlequin frogs have also shown resistance to chytrid, but experts don't yet know it the animals are adapting—or just lucky. (See "African Clawed Frog Spreads Deadly Amphibian Fungus.")

"The prospects are that the fungus will cause high mortality in this population," Gratwicke said of the 530 newly released frogs.

Even so, this population will help determine where to release more captive frogs in the future.