Tag Archives: amphibian

Dead frog killed by Chytridiomycosis. Credit: Wikimedia Commons.

An amphibian fungus has caused the worst mass extinction in recent history

Dead frog killed by Chytridiomycosis. Credit: Wikimedia Commons.

Dead frog killed by Chytridiomycosis. Credit: Wikimedia Commons.

A fungus that gruesomely kills frogs and other amphibians is responsible for the biggest decline in wildlife in recorded history. In the past 50 years since the first outbreaks were signaled by biologists, the disease, known as chytridiomycosis, has caused the extinction of 90 species and wiped out 90% of the populations of another 124 species.

Chytridiomycosis is caused by a fungus called Batrachochytrium dendrobatidis — or Bd for short. The fungus is believed to have originated in Asia where it was confined to certain hotspots. However, it started to spread across the world in the early 20th century, during a period when international trade was booming. Along with spices, porcelain, and various other goods, Western sailors also carried Bd from port to port via infected stowaway animals. Today, Bd is present in over 60 countries across five continents.

Biologists first noticed in the ’70s and ’80s that amphibian populations began to suddenly decline or outright disappear. It wasn’t until 1998 that this decline was associated with Bd and the scope of the crisis became apparent. But a recent analysis suggests that the situation is even worse than some have feared. According to new data compiled by researchers at the Australian National University, the fungus is responsible for the decline of 501 species of frogs and other amphibians — that’s 6.5% of all known amphibians. Australia, Central America, and South America are particularly hard hit, say the authors.

“Highly virulent wildlife disease, including chytridiomycosis, is contributing to the Earth’s sixth mass extinction,” said Dr. Ben Scheele of The Australian National University in Canberra, the lead author of the new study.

“We’ve lost some really amazing species.”

Each bar represents a single species hit by the fungus. The color shows the extent of population decline or extinction. Credit: Scheele et al., Science.

Each bar represents a single species hit by the fungus. The color shows the extent of population decline or extinction. Credit: Scheele et al., Science.

The fungus is really after nutrients found on the amphibians’ skin. However, it also feasts on the tissue of the animals, eating away their skin and triggering fatal heart attacks. The disease spreads through the water and can persist outside the host which makes traditional tactics for fighting invasive species useless. This isn’t some feral cat or rodent, but a microorganism that virtually permeates the entire environment once it gets a footing.

“It’s a staggering thing to consider,” said one of the study’s authors, Jonathan Kolby, in an interview with the Washington Post. “We’ve never before had a single disease that had the power to make multiple species extinct, on multiple continents, all at the same time.”

There is a glimmer of hope, though. The findings suggest that 60 species have shown signs of recovery. Perhaps some sturdy individuals have the necessary adaptations to keep the disease at bay. But no one can tell for certain whether amphibians are starting to develop an evolutionary edge against the fungus or it’s just a matter of time before a new outbreak comes to deliver the killing blow.

As if Bd wasn’t enough, amphibian species across the world are threatened by habitat loss, exploitation, and climate change — these are still the main threats for thousands of species. The best thing we can do right now is to shelter currently untouched population from Bd by restricting access to sanctuaries. Some research groups are breeding individuals from contaminated habitats in captivity in hopes of averting a species’ total annihilation.

“It’s really hard to remove chytrid fungus from an ecosystem — if it is in an ecosystem, it’s pretty much there to stay unfortunately. This is partly because some species aren’t killed by the disease,” Scheele said.

“On the one hand, it’s lucky that some species are resistant to chytrid fungus; but on the other hand, it means that these species carry the fungus and act as a reservoir for it so there’s a constant source of the fungus in the environment.

But, the truth is that there is not one thing we can do to significantly improve the odds of survival of infected habitats or, for that matter, stave off the spread of Bd. And this makes this killer fungus incredibly scary.

Juliet with Teresa Camacho Badani. Credit: by Robin Moore, Global Wildlife Conservation.

Romeo, once the loneliest the frog in the world, finds a mate!

Romeo the bachelor Sehuencas water frog. Credit: Dirk Ercken and Arturo Muñoz.

More than ten years ago, biologists collected Romeo — a Sehuencas water frog — from a stream in Bolivia. They knew that the species was in big trouble and a conservation effort had to be urgently ramped up, but despite numerous subsequent searches, no other specimen had been found. Things were looking pretty bleak for the loneliest frog in the world until recently when an expedition formed by Global Wildlife Conservation and the Museo de Historia Natural Alcide d’Orbigny rescued five individuals: three males and two females. It looks Romeo may have found his Juliet after all!

“It is an incredible feeling to know that thanks to everyone who believes in true love and donated for Valentine’s Day last year, we have already found a mate for Romeo and can establish a conservation breeding program with more than a single pair,” Teresa Camacho Badani, the museum’s chief of herpetology and the expedition leader, said in a press release. “Now the real work begins—we know how to successfully care for this species in captivity, but now we will learn about its reproduction, while also getting back into the field to better understand if any more frogs may be left and if so, how many, where they are, and more about the threats they face. With this knowledge we can develop strategies to mitigate the threats to the species’ habitat, while working on a long-term plan to return Romeo’s future babies to their wild home, preventing the extinction of the Sehuencas water frog.”

The expedition team — which included Camacho Badani, veterinarian Ricardo Zurita Urgarte, Sophia Barrón Lavayen, the head of conservation breeding for the K’ayra Center; and researcher Stephane Knoll — spent months analyzing historical records of where the species had originally been found, in order to find the best spots.

Although the researchers looked for the frogs in streams that had the perfect conditions, including in a stream where Camacho Badani had found Sehuencas water frogs ten years ago, they came out empty handed. At the end of one fateful day, when the whole team was exhausted and wet, they decided to try their luck just one more time. So they investigated a waterfall at the end of a stream and much to everyone’s surprise, the daring explorers found the much-sought-after amphibians.

“I thought it was a Quechua Toad (Rhinella quechua), also called an Incachaca Toad, which is a threatened species. I told the team to stay alert because I planned to catch the frog to confirm it wasn’t a Sehuencas Water Frog, and then let it go. I got into the pond while the water splashed all over me and dove my hands into the bottom of the pond, where I managed to catch the frog. When I pulled it out, I saw an orange belly and suddenly realized that what I had in my hands was the long-awaited Sehuencas Water Frog. My first reaction was to yell “I found one!” and the team came running over to help me and pull the frog to safety,” Camacho Badani said in an interview for the Global Wildlife Conservation blog.

Juliet with Teresa Camacho Badani. Credit: by Robin Moore, Global Wildlife Conservation.

Juliet with Teresa Camacho Badani. Credit: by Robin Moore, Global Wildlife Conservation.

The Sehuencas water frog (Telmatobius yuracare) was once commonly found on the bottom of small streams or rivers in the inaccessible Bolivian mountain cloud forests. But a combination of pollution, climate change, and a contagious and deadly pathogen placed Telmatobius on the brink of extinction. The newly rescued frogs, among them a Juliet for Romeo, are currently in quarantine as they acclimate to an environment that replicates the conditions in the wild. Conservationists also want to make sure that the frogs aren’t affected by chytridiomycosis, the infectious disease that claimed most of the wild population.

“We do not want Romeo to get sick on his first date! When the treatment is finished, we can finally give Romeo what we hope is a romantic encounter with his Juliet,” Camacho Badani said.

The expedition was launched after Global Wildlife Conservation completed a successful Valentine’s Day fundraiser last year. People from more than 32 countries were impressed by Romeo’s call for a mate in his Match profile and made donations. The funds were matched by Match for a total of $25,000.

In the future, the team plans to look for more frogs through March to better assess the state of the wild Sehuencas water frog population, as well as also to test for the presence of chytridiomycosis. This way, conservation efforts will be better equipped when the time is right to return Romeo’s offspring to the Bolivian mountain springs where they belong.

Previously, similar efforts successfully boosted endangered amphibian populations such as the Mallorcan midwife toad in Spain or the Kihansi spray toad in Tanzania.

Blind creature that buries its head in the sand named after Donald Trump

The unusual amphibian’s behavior was compared to Trump’s approach to global warming.

When you add the hair, the resemblance is uncanny. Image credits: Envirobuild.

Trump the caecilian

Dermophis donaldtrumpi was discovered in Panama. It is a caecilian — a group of limbless, serpentine amphibians which mostly live underground or hidden around streams. As it so often happens in modern times, its scientific name was auctioned, with the money going to charity (in this case, the Rainforest Trust charity).

The naming rights were purchased by EnviroBuild, a sustainable building materials company, who paid $25,000 (£19,800) at an auction for the right. The company said it wants to raise awareness about climate change, likening the creature’s behavior of burying its head underground to Donald Trump’s refusal to accept man-made climate change, although its effects are already affecting American people.

“[Dermophis donaldtrumpi] is particularly susceptible to the impacts of climate change and is therefore in danger of becoming extinct as a direct result of its namesake’s climate policies,” said EnviroBuild co-founder Aidan Bell in a statement.

“Burrowing [his] head underground helps Donald Trump when avoiding scientific consensus on anthropomorphic climate change,” he wrote.

Amphibians are indeed some of the most vulnerable creatures in the face of climate change and habitat destruction. In addition to expressing his intention to withdraw from the Paris Agreement, Trump has also consistently pushed policies that support the fossil fuel industry — the main contributor to man-made global warming. However, Trump has consistently denied the fact that man-made global warming is happening.

“I don’t know that it’s manmade,” he said in an interview with CBS’s 60 Minutes in October. “I’m not denying climate change but [temperatures] could very well go back,” he added, without offering evidence.

Just last month, Trump questioned a report which concluded that climate change would cost the US hundreds of billions of dollars annually and damage health. That report was carried out by his very own government and federal scientists.

“I don’t believe it,” he told reporters at the time.

This is exactly why the new, blind amphibian has been named after Trump, Bell explains.

“It is the perfect name. Caecilian is taken from the Latin caecus, meaning ‘blind’, perfectly mirroring the strategic vision President Trump has consistently shown towards climate change.”

This isn’t the first animal to be named after Donald Trump. A recently-discovered moth species was also named after him by biologist Vazrick Nazari. Nazari said the moth’s “hairstyle” reminded him of Trump. However, Barack Obama holds the record for most species named after a US President: 14.

A captive Oriental fire-bellied toad (Bombina orientalis) imported into Europe from South Korea. Credit: Frank Pasmans.

Deadly fungus threatening to wipe out amphibians around the world traced to Korea

A rapidly spreading and lethal species of fungus that has devastated amphibian populations around the globe likely originated in East Asia. The authors of the new study say that monitoring and regulating the transit of amphibians, particularly those involved in pet trade, is essential in order to secure amphibian populations from such a dangerous and rapidly expanding disease.

A captive Oriental fire-bellied toad (Bombina orientalis) imported into Europe from South Korea. Credit: Frank Pasmans.

A captive Oriental fire-bellied toad (Bombina orientalis) imported into Europe from South Korea. Credit: Frank Pasmans.

The fungus in question is Batrachochytrium dendrobatidis (Bd), also known as chytrid fungus. When it infects a host, the fungus causes a disease called chytridiomycosis, which attacks the animal’s skin, affecting the ability to regulate water and electrolyte levels. Eventually, the animal dies of heart failure. Frogs, toads, newts, and other amphibians across several continents are affected by the disease.

Previous attempts to discover the origin of this very dangerous and fairly recent pathogen suggested the fungus first appeared in South Africa, where it infected  African clawed frogs (Xenopus laevis). It wasn’t along until this hypothesis was challenging as other research groups found that Bd samples taken from African frogs had too little genetic diversity.

Now, an international collaboration spanning 38 institutions reported their findings after sequencing the genomes of 234 samples collected from all around the world. Researchers looked at the minute differences between the genomes, identifying four distinct lineages. Three of them are distributed globally but a fourth appears only in Korea, in some of the frogs that are native in the region.

On a closer look, the Korean lineage contains much more genetic diversity than any other lineage. What’s more, the Korean Bd showed no history of global outbreaks within their genomes, which can only mean that the Korean chytrid strains were native to the region, and most closely resemble the ancestor of all modern Bd.

The team led by Simon O’Hanlon from Imperial College London estimated that the killer strain of Bd diverged from its most common ancestor between 50 and 120 years ago. That’s around the time intercontinental trade started rapidly expanding.

“Biologists have known since the 1990s that Bd was behind the decline of many amphibian species, but until now we haven’t been able to identify exactly where it came from,” O’Hanlon said in a statement.

“In our paper, we solve this problem and show that the lineage which has caused such devastation can be traced back to East Asia.”

According to the researchers, it is the human movement of amphibians — particularly through the pet trade — that has contributed the most to the spread of the pathogen around the world. Sightings of Asian strains of Bd in pet Oriental fire-bellied toads add weights to this idea.

The research suggests that since East Asia is ground zero for the deadly fungal pathogen, then ongoing trade in infected animals should be halted at once otherwise we risk threatening the already fragile amphibian biodiversity.

Scientific reference: S.J. O’Hanlon el al., “Recent Asian origin of chytrid fungi causing global amphibian declines,” Science (2018). science.sciencemag.org/cgi/doi … 1126/science.aar1965.