ESSAY

 

We must safeguard the web of life and care about the other living species that we share this planet with. Pygmy tarsiers eat and host bugs that we’ve seen at home — insects, spiders, lizards, bedbugs, lice, fleas, roundworms, and tapeworms.  The vaquitas are preyed upon by large sharks and killer whales, keeping them away from us. But only 10 vaquitas are left and in their absence, the diet of sharks and whales may change. A tiger in the wild indicates that the forest it inhabits is healthy and diverse. As of now, there are 3,900 tigers in the wild globally, and more than twice as many (8,000) in captivity. By protecting the web of life, we build a kinder world for everyone.

For the first time, over 40 organizations from 13 countries have joined forces through the Atelopus Survival Initiative (ASI), to save the harlequin toads in South and Central America from extinction.

The International Union for Conservation of Nature (IUCN) said 83% of  94 harlequin toad species are threatened with extinction, and 40% were last seen in the early 2000s. The IUCN lists four species as extinct, but the number is presumably higher.

In the past, harlequin toads were studied by conservationists individually, but  Lina Valencia, ASI founder and co-coordinator of the IUCN SSC Amphibian Specialist Group Atelopus Task Force said “We need a constellation of champions working together to bring harlequin toads back from the brink of extinction.”

Valencia, who is also Andean countries coordinator for Re:wild, one of ASI’s primary conveners, said solutions must address chytridiomycosis, the disease that almost totally wiped out harlequin toads and other amphibians globally. Other main threats are climate change, habitat destruction, hunting, and introducing invasive species such as the rainbow trout (which devours hundreds of harlequin eggs in one gulp).

The amphibian apocalypse

A global pandemic resulted in declines of 501 amphibian species and rendered 90 amphibians extinct worldwide. The hardest hit was South and Central America’s harlequin toads, which were largely destroyed within 30 years.  The infectious disease, chytridiomycosis, is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd).

“It’s hypothesized that if we don’t do anything, [the harlequin toads] will be the first genus of vertebrates to go extinct,” said Valencia. Through ASI, resources can be maximized, and expertise, capacities, knowledge, and experience can be shared. Together they hope to achieve the following by 2041:

  • Develop and implement innovative ways to address chytrid’s impact on harlequin toads, and learn why some species are less susceptible to the effects of chytrid.

  • Protect and restore these toads’ forests and watersheds.

  • Create and maintain conservation breeding programs.

  • Search for lost species and fill gaps in scientific knowledge about harlequin toads.

  • Share stories to transform these toads into symbols of hope for the region and the world, as a flagship of conservation success; and demonstrate commitment to conserving harlequin toads.

  • Ensure the Atelopus conservation network has the technical, logistical, and financial support to secure long-term conservation for these toads.

Hello, harlequin toads

Harlequin toads are dually hued in blends of orange, gold, blue, black, brown, bright red, yellow, purple, green, and pink, creating lovely patterns on smooth skin. There are 100 species of harlequin toads, and the variation among species is wide. Some live in sea-level woodlands. Others thrive on snow lines along the Andean paramos, 4,500 meters high.

These toads are endemic to Costa Rica, Bolivia, Ecuador, French Guiana, Brazil, Colombia, Guyana, Panama, Peru, Suriname, and Venezuela in South and Central America. Panama’s national animal is the Panamanian harlequin golden toad.

The smallest species is the length of a human baby’s thumb; the largest, the size of an adult thumb. They are masters at hiding in forests but emerge en masse during mating season, hiking to streams and creeks in search of mates. Sometimes males fight to get first dibs on the water.

At the noisy river, the males wave at females, and if accepted, the female will wave back. Some toads wait for days for a mate. When together, they embrace amplexus style, where the smaller male rides on the female’s back. Most toads hug for two days, but harlequin toads will hug for weeks. The males won’t eat and may lose 30% of their body weight. When the female lays her eggs on boulders and rocks, the male fertilizes them.

A painful death

Harlequin toads source water, salt, and breathe through their sensitive skins (and lungs). The infectious disease chytridiomycosis covers the harlequin toad’s entire skin, disabling them from absorbing water and regulating salt intake. The disease then eats the toad’s skin until the toad gets a heart attack after 21 days.

Chytrid Bd’s mysterious origin

It isn’t known where the fungus chytrid Bd originated, but author Ché Weldon, et. al. said that the sudden declines and deaths of amphibians occurred in large numbers. Therefore, chytrid Bd was not endemic to affected regions.

Instead, the fungus was introduced by traders to North America (1961), Australia (1978), Central America (1983), South America (1986), Europe (1997), and Oceania (1999).

The earliest discovery of an amphibian with chytridiomycosis was in 1938 in an  X. laevis toad in South Africa.  However, as of 2001, there was no huge decline of amphibians, so Weldon et. al. suggest that chytrid Bd is endemic to South Africa.

Trade began in South Africa in the early 1930s, and the X. laevis frog was in great demand. These frogs provided plenty of large, strong eggs that were easy for embryologists to experiment with.

Embryology and pregnancy tests

Wilhelm Roux experimented with frog embryos in the 1880s. By the 1930s researchers lacked frog eggs to study, so the X. laevis frog, with its many eggs, was in great demand.

Scientists learned that a female X. laevis could ovulate if injected with the urine of a pregnant woman. This became the official pregnancy test from 1940–1950, and many hospitals kept a supply of X. laevis frogs in their labs. It’s likely that some frogs escaped and went to the wild.

A perfect carrier

X. laevis frogs became perfect carriers and spreaders of chytridiomycosis. In the wild, the fungus went from forest soils to rivers and streams. Che Weldon et. al. said, “In the importing country, escaped frogs, the water they lived in, [or soil] or both, could have come into contact with local amphibian species, and subsequent transmission of the disease could have followed.”

From 1998–2004, over 10,000 frogs were exported annually and brought to 132 institutions from 30 nations. Weldon added, “The establishment of feral populations of X. laevis in Ascension Island, the United Kingdom, the United States, and Chile in 1944, 1962, the 1960s, and 1985, respectively, show that transmission could have been ongoing if these feral populations were infected.”

In the 1980s and 1990s, a drastic decline of harlequin toads was documented, and no evidence shows that population declines have ended, despite the fact that two extant subpopulations were found in Costa Rica, and some species were recently recorded in Panama.

A pandemic recipe 

There are hundreds of chytrid fungi species, most of them innocuous. But Bd. thrives on protein from amphibian skins. Globally, it evolved into an extremely poisonous strain that caused the amphibian pandemic, infecting 695 species in varying degrees. Although some amphibians tolerated Bd, many others couldn’t.

“In some respects, it’s the perfect pandemic recipe,” says biologist Dan Greenberg, a Ph.D. student at Simon Fraser University. “If it were a human pathogen, it’d be in a zombie film.”

Stepping on harlequins

Panamanian biologist Edgardo Griffith said that seven years ago he and his team stepped carefully on a creek because “There were so many golden toads” and they didn’t want to harm them. This time, they only found one golden toad after walking along the creek for 30 minutes.

 Some harlequin species that were presumed to be extinct have resurfaced but in dangerously few numbers. Among them are:

  • 200 Atelus varius found in a mountain reserve in Costa Rica

  • The Starry Night Harlequin Toad, protected by the indigenous Arhuaco community of Sogrome, due to spiritual beliefs

  • The Azuay stubfoot toad found in a mountain forest in Ecuador

  • Four longnose harlequin toads in Ecuador.

In the past 10 years, field searches by biologists, locals, and others led to finding some lost species and discovering new ones. However, the species’ numbers are far lower than before. The information from these findings will enable scientists to re-evaluate the harlequin toads’ status and update conservation strategies for their protection.

Bred in captivity

In March 2021, 17 harlequin tadpoles were bred in captivity for the first time in Manchester Museum, UK, after three years spent breeding six Atelopus varius adults. Andrew Gray, the curator of herpetology at the museum, said they studied and replicated the conditions that made breeding harlequin toads and their laying eggs successful. Gray said that if the species goes extinct, those bred in captivity can be brought back into the wild.

There are 68 species of the Atelopus genus, and the Panama Wildlife Conservation (PWC),  has teamed up with the University of Manchester Museum to breed its “back-up” population in England. The PWC is also holding workshops for local schoolchildren, so they will understand and value these toads, and protect them. Gray said they’re raising funds to support the training program and to return the toads to their natural habitat.

Environmental contributions of harlequin toads 

Harlequin toads are vital to the environment because of their sensitive skin, through which they can immediately know if environmental changes have occurred. This knowledge is helpful to other forest inhabitants within the same ecosystem.

The harlequin tadpoles require clean, healthy water.  Their presence in a stream indicates the water is clean and its quality is good. Other species benefit from this information, as well as humans. The presence of harlequin toads in a forest indicates a healthy habitat, allowing humans to know in advance if an environment is distressed and may affect us directly, or if it’s healthy.

The harlequin toads help balance the insect populations because they eat termites, bugs, spiders, ants, and other arthropods. The only known predator of harlequin toads is the sarcophagid fly, Notochaeta bufonivora, which gives birth to living larvae that they deposit on the toad’s rear thigh. The larvae dig deep within the harlequin toad’s body and eat it from inside, killing the toad within days.

What is being done

The ASI’s Harlequin Toad (Atelopus) Conservation Action Plan (HarleCAP) provides the roadmap for conserving and restoring harlequin toads as a genus and their habitat.

“Protecting and restoring harlequin toads and their habitats will also benefit the species that share the ecosystems in which they live and that provide water to tens of millions of people, and ultimately all life on Earth,” Valencia said. “And we’re hoping that the ASI will be a successful model that conservationists can emulate for other groups of threatened species.”

Participating members of ASI

The members of ASI include: National and international conservation groups, zoos, captive breeding centers, academic institutions, governments and local communities. Its current members represent the following organizations: Amphibian Ark, Amphibian Survival Alliance, Asociación Pro Fauna Silvestre – Ayacucho, Bioparque Municipal Vesty Pakos, Bolivian Amphibian Initiative, Centre National de la Recherche Scientifique, Centro de Conservación de Anfibios AMARU, Centro Jambatu de Investigación y Conservación de Anfibios/Fundación Jambatu, CORBIDI, DoTS, El Valle Amphibian Conservation Center Foundation, Facultad Latinoamericana de Ciencias Sociales, Florida International University, Fort Worth Zoo, Fundación Atelopus, Fundación Zoológica de Cali, Universidad del Tolima (GHEE), Grupo de Trabajo Atelopus Venezuela, Image Conservation, Instituto Nacional de Pesquisas da Amazônia, Instituto Venezolano de, Investigaciones Científicas, Ministerio del Ambiente de Perú, MUBI (Museo de Biodiversidad del Perú), Parque Explora, Parque Nacional Natural Puracé, Photo Wildlife Tours, Pontificia Universidad Católica del Ecuador, Pontificia Universidad Javeriana, Re:wild, San Diego State University, Smithsonian Tropical Research Institute, Trier University, Universidad de Antioquia, Universidad de Costa Rica, Universidad de los Andes, Universidad del Tolima, Universidad del Magdalena, Universidade Federal do Pará, Universidad Nacional, Universidad Interamericana de Panamá, Universidad Nacional de Colombia, Universidad San Francisco de Quito, Universidade Estadual de Campinas, Universidade Federal do Oeste do Pará, University of Nevada, Reno, University of Notre Dame, University of Pittsburgh, WCS (Wildlife Conservation Society), WCS Colombia, and Zoológico Cuenca Bioparque Amaru.