A tale of two frogs: The tough uphill battle for rediscovered species

In 2021, a group of scientists in Ecuador looked in disbelief at a photo of a chocolate-colored frog with an orange belly. The researchers wondered: Could it be Atelopus guanujo — the Guanujo stubfoot toad — a species of harlequin frog that hadn’t been seen since 1988 and thought to be extinct?

At first, “you can’t really believe that you’re looking at a lost species!” said conservation biologist Andrea Terán-Valdez, a research team member from the Jambatu Center for Amphibian Research and Conservation in San Rafael.

A. guanujo, once abundant across Ecuador’s central Andes Mountains, like many other harlequin frogs, had diminished and vanished as habitat degradation, climate change, and the deadly amphibian chytrid fungus intensified in the region.

Fortunately, since 2018, a priest had been showing pictures of several so-called lost species to community members in case anyone chanced across them. And when in 2021, someone in the small town of Simiátug recognized a male frog in a pasture as one the priest had shown, the priest alerted the Jambatu Center’s director Luis A. Coloma. Finding this single male shone a beacon of hope for the species, Terán-Valdez said.

But as efforts to find a female bore little fruit, A. guanujo’s future began to look more complicated. When they first looked in the area where the malle was discovered, “we couldn’t find anything else,” Terán-Valdez said.

Hope transcendent and deferred

Every year, the world’s scientists rediscover a number of species that were lost to science or feared extinct, mostly in tropical regions. Terán-Valdez and her colleagues, for example, estimate that up to 37% of more than 70 putatively-extinct species of harlequin frogs have been found alive.

While rediscoveries are often celebrated by the media as a sign for hope in the face of the global extinction crisis, many scientists caution that rediscovery doesn’t equal population recovery. One 2011 study found that 86% of rediscovered birds and mammals remained highly threatened years later. That figure rose to 92% for amphibians, which are especially vulnerable due to the chytrid fungus and their small ranges.

While not all rediscovered species are experiencing declines, ones that are can have the deck stacked against them. For some species when they’re found, it can turn out that habitat degradation or disease have already pushed them to extremely low population densities, very limited genetic diversity and small distributions. “Pulling species out once they’re in an ‘extinction vortex’ is a rather large effort,” said conservation biologist Christina Biggs, a lost species officer at the non-profit Re:wild.

The story of A. guanujo illustrates the immense conservation challenges rediscovered species can face, particularly in highly biodiverse regions such as in South America, which are especially hard hit by climate change and amphibian disease. Additional challenges include stiff competition for restoration funding and scant legal protections and government support for endangered species, Terán-Valdez said.

The situation in Latin America contrasts with other regions like the U.S. where rediscovered species, such as the dusky gopher frog (Lithobates sevosus) benefit from robust conservation laws and sustained government funding. With enough money, personnel, legal protection, and a great deal of luck, rediscoveries can be what they should be: powerful catalysts to truly bring imperiled species back to life.

“Rediscovered species … may not be extinct, but they’re hanging on by their fingernails,” said conservation scientist Stuart Pimm of Duke University. “But — and I think it’s an important but — it does mean there is still some hope for those species.”

The search for the Guanujo stubfoot toad

Recent decades have seen a growing number of rediscovered amphibians, birds and mammals, although recent data on “lost” species not documented in a decade or more suggest that rates have slowed somewhat. Species go missing to science for a number of reasons, Biggs said; many simply haven’t been looked for due to lack of interest or living in remote, hard-to-access habitats, while others become harder to find due to population declines. Stories of rediscoveries range from species that scientists haven’t looked for recently and then rediscovered via targeted expeditions, to species believed extinct, like A. guanujo, that then popped up out of the blue.

The first step required after an animal is seemingly rediscovered is to verify the identity of the species_, which can be difficult because a small pool of individuals won’t portray a species’ full range of variation. For instance, the A. guanujo male toad found in Ecuador looked markedly darker than bright orange ones previously documented.

That may be because the male could be a hybrid between A. guanujo and the jet-black, orange-bellied harlequin frog (Atelopus ignescens). But until DNA can be extracted from old, formalin-preserved guanujo specimens and compared, Terán-Valdez and her colleagues will treat the male like A. guanujo, she said.

Making things more challenging, she and her colleagues know very little about A. guanujo’s natural behaviors or ecology, as the species went missing before it could be scientifically studied. It’s a mystery at this point as to how the male managed to persist, and whether an existing population is large enough to be genetically viable. Though chytrid fungus has long been known in the region, it has become deadlier since the late 1980s — possibly because climate change has made cool, mountainous habitats more conducive to its spread, and frogs more vulnerable, Terán-Valdez said.

Given A. guanujo’s shaky odds of natural survival, the male was taken to a lab in hopes of breeding a backup colony. Once initial searches for a female failed, Terán-Valdez applied to local conservation organizations for funding to do more extensive searches. Working with a grant of only $700, she and her colleagues trained young people from the local community to look for the toad, peeking underneath rocks at the edge of pastures.

After three months of searching, “we still couldn’t find it,” Terán-Valdez said.

Finally, a month later, she received a WhatsApp message from someone who had chanced upon another brown, orange-bellied frog — this time larger and missing the male breeding glands. It was a female, “a beautiful female,” Terán-Valdez recalled. But in a tragic twist of fate, bad cell reception had delayed the message by two weeks. When the community members didn’t immediately hear back from Terán-Valdez, they released the frog back into the wild.

Jambatu Center has had more luck with other harlequin frogs, such as A. ignescens, which was rediscovered in 2016 in northern Ecuador. While nearly a few dozen frogs continue to persist at that location, Terán-Valdez and her colleagues have succeeded in breeding a backup population. They’re now working to breed a large population that can someday be reintroduced into the wild.

“Not that we can guarantee that it’s going to survive,” Terán-Valdez said, but “that’s a good example that I think gives us hope.”

As for A. guanujo, the team eventually called off the search when funding ran out. The male has since died — although the team extracted and cryopreserved its sperm, in the hope of breeding offspring through in vitro fertilization if a female does show up.

In 2022, surveys for environmental DNA — snippets of DNA that species shed into their environment via skin cells, fur, fluids or other tissue — revealed positive samples for A. guanujo in local creeks, suggesting there are other individuals out there. “But it’s just that the density of the population is so low, there are so few individuals — that’s our guess — that it’s very difficult to find them,” Terán-Valdez said.

The comeback of the dusky gopher frog

The dusky gopher frog also had a bleak outlook when rediscovered. It hadn’t been spotted in the U.S. states of Mississippi, Louisiana or Alabama since the 1960s, until herpetologist Glen Johnson, his brothers and friends received a small grant to go looking for it.

While the others were less inclined to drive from pond to pond at night after heavy winter rains, Glen Johnson persevered. In 1987, he finally heard the call the males use to lure females — a deep guttural snore — at two ponds. The next year, he found what he was looking for: a breeding congregation at a pond in Mississippi’s De Soto National Forest.

Until then, nobody had known just how bad things were for the dusky gopher frog, which mostly dwells underground in stump holes or gopher tortoise burrows in longleaf pine savannas. Over much of its range, forest habitat had been lost to farmland, timber plantations and urban development, explains ecologist Joe Pechmann of Western Carolina University, principal investigator for dusky gopher frog research and recovery. Many of the open-canopy seasonal ponds where the frog breeds had been filled in or otherwise degraded, or overgrown with trees due to years of fire suppression and inadequate burning. While chytrid fungus doesn’t seem to affect the species — probably thanks to warm Gulf Coast temperatures — other amphibian diseases may have contributed to its decline.

For years, “Glen’s pond” housed the only sustained population of gopher frogs. “I think we owe it to the frog to try and maintain their existence, since it is largely due to human activity that this population teeters on the edge of extinction,” Johnson said.

Fortunately for the gopher frog, it lived in a part of the world where conservation was relatively well financed. The U.S. Fish and Wildlife Service (USFWS )funded the restoration effort, using money set aside specifically to protect and recover endangered species, with Mississippi also contributing “pass thru” funds, most of which also stemmed from USFWS.

In 2001, Pechmann and others began collecting eggs at Glen’s pond, knowing that only a few percent would likely make it to adulthood in the wild — or even less as climate change-driven dry conditions escalated across the region. They tended the eggs, which hatched into tadpoles, then into froglets in outdoor tanks, which they then released back into the pond.

“They probably would have gone extinct if we had not been doing that,” Pechmann said. “The pond dried too soon for nine years in a row.”

Meanwhile, in De Soto National Forest, the U.S. Forest Service began clearing trees from small ponds, making them deeper and more suitable for gopher frogs. Then some froglets were translocated there.

Other organizations joined in — including The Nature Conservancy, the University of Southern Mississippi, Memphis Zoo and other zoos, and the U.S. Army Corps of Engineers — contributing to raising froglets, starting new populations, and supplementing existing ones in the wild. Though researchers have seen frogs surviving and breeding at some translocation sites, “it remains to be seen whether these sites have viable populations,” said USFWS fish and wildlife biologist John Tupy.

Today, Mississippi is home to around 500 adult dusky gopher frogs, according to 2021 estimates. Most of them live around Glen’s pond, Tupy said. For now, the frog’s future still relies on tadpole-raising and translocation to keep populations going, especially with climate change making the Southeastern U.S. ponds more likely to dry early.

“They’re definitely on the road to recovery, but they have a long way to go,” Pechmann said.

Ingredients for recovery

Government funding was key to the gopher frog’s recovery, Pechmann said. Though conservation funding is always competitive, the species “has done fairly well for a frog,” likely because it is so endangered, despite the recovery efforts, Pechmann said.

The frog was also lucky to have two especially passionate USFWS officials — Tupy and Linda LaClaire — to advocate for its conservation within the agency, Pechmann adds. The fact that the frog was listed as a Mississippi state endangered species — and since 2001, was federally listed under the Endangered Species Act — was also important to securing ongoing funding, justifying greater habitat protection for the frog, and bringing more attention to its dire status, Pechmann and Tupy added.

By contrast, many harlequin frog species in Ecuador occur outside conserved areas, offering them little to no legal protection. It took a lawsuit to stop a copper mining project at one site that is home to the only known population of Atelopus longirostris.

Just as important, there are limited funds in Ecuador to support the conservation of amphibian species, Terán-Valdez noted. With the majority of Ecuador’s 635 amphibian species threatened, funding competition is high, and all must compete against other animals perceived to be more charismatic, like jaguars (Panthera onca), she said.

While she believes environmental ministries should lead the way in species conservation, in many Latin American countries the task instead falls to civil society, foundations, and non-profits. And the current strategy is to give many small grants as opposed to a few larger ones, which doesn’t serve long-term restoration well. Terán-Valdez said she and her colleagues are continuously seeking funding for harlequin frogs, many of which she considers a conservation emergency.

Money, perseverance, and luck

Globally, rediscovered species experience a variety of outcomes. Many that were lost simply due to lack of targeted search efforts can turn out to be doing just fine. Others haven’t been spotted again since their rediscovery, like Bachman’s warbler (Vermivora bachmanii) in the U.S. last seen in 1988 — while others are so few in number they risk meeting a genetic dead end, said Wesley Knapp, the chief botanist at the conservation non-profit NatureServe. “Some species are doomed to extinction no matter what we do,” Knapp said.

Some rediscovered birds have so little habitat left that their prospects for recovery are bleak, Pimm added, while still other species have such small populations they could be wiped out by a single event, like some potentially rediscovered U.S. plant species whose only known population lie inside mining exploration sites. Even in the U.S., the Endangered Species Act is no panacea for rediscovered species, as the listing process can take much longer than struggling species have, Knapp noted. “I really wish there was a process … where they preemptively petition all these ‘extinct’ plants so if they’re rediscovered, they’re automatically protected.”

There are examples from around the world where conservation efforts have managed to — or are working to — overcome the challenges that rediscovered species face, Pimm noted. But expensive conservation actions are still most likely to be undertaken in wealthy jurisdictions with strong conservation laws, according to ecologist and conservation biologist Diana Fisher of the University of Queensland in Australia: Prominent examples include the breeding programs for the black-footed ferret (Mustela nigripes) launched in the U.S., or the eradication of invasive predators like rats and cats from islands to protect the New Zealand storm petrel (Fregetta maoriana).

In general, though, there are too many instances of rediscovered species not getting the attention and funding they need, notably including many small-bodied tropical forest mammals, Fisher’s research has found.

The outcomes for rediscovered species also depend on who finds them, she added: “People from wealthy countries have traditionally led short-term expeditions to search for new and missing species, then they returned home without following through with longer-term conservation plans.”

Efforts to find and conserve species are more likely to succeed if local communities and institutions are involved, Fisher added. That’s why Re:wild’s “Search For Lost Species” program — which works to find species that haven’t been spotted in a decade or more — joins with local communities, governments, scientists, and non-profits to develop a conservation pipeline before it even starts looking for lost species, Biggs said.

That kind of coordinated effort can bring success: Since its rediscovery in 2019, the silver-backed chevrotain, also known as the Vietnam mouse-deer (Tragulus versicolor), has been well supported by anti-snaring programs, ranger protection programs, and the construction of a breeding center, while the rediscovery of the Pernambuco holly tree (Ilex sapiiformis) in Brazil last year immediately triggered an analysis to create a Key Biodiversity Area around its habitat, Biggs noted.

Terán-Valdez and her colleagues continue working with local communities in Ecuador to study and monitor harlequin frog populations, protect their habitat, and promote shifts to local agricultural practices that are more compatible with frog survival. The big limitation remains funding. The Jambatu Center never officially reported the rediscovery of A. guanujo, in part because of the taxonomic uncertainty around its identity, but also to avoid giving false hope. There is hope as soon as even a single individual is rediscovered, Terán-Valdez stresses, but it takes a lot of funding, work, knowledge and luck to turn hope into reality.

Pechmann likens rediscovering a lost species to rushing an animal to a hospital emergency room in critical condition: “Lots of things have got to go right to recover it.”

Banner image: In 2021, a resident of the small Ecuadorian town of Simiátug found a male frog putatively belonging to the long-lost species Atelopus guanujo. Image by Steven Guevara S. / Centro Jambatu. 

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Citations:

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Article published by Glenn Scherer

Amphibian Crisis, Amphibians, Animals, Biodiversity, Climate Change And Biodiversity, Conservation, Deforestation, Endangered Species, Environment, Extinction, Forests, Frogs, Green, Happy-upbeat Environmental, Herps, New Discovery, Rainforests, Rediscovered Species, Tropical Forests, Wildlife, Wildlife Conservation

Ecuador, North America, South America, United States

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