Amphibians on red alert: what their “pandemic” tells us about the health of the planet

If the amphibians are to the planet what canaries are to mines – an indicator of toxic gases when they stopped singing and/or died – the data known today indicate that it is time to take the environmental crisis very seriously: almost half of the species (41%) is on red alert.

Climate change and several lethal diseases have plunged this group of vertebrates into a “massive pandemic”according to the great scientific report on the state of amphibians in the world published today by Nature magazine, with the participation of more than one hundred researchers coordinated by the International Union for Conservation of Nature (IUCN).

This is the second review of the status of amphibians after the first, in 2004, raised alarm bells about the state of their populations.

Researchers have evaluated almost 9,000 species, 2,286 of them studied for the first time, and found that the 41% is in danger, a fact that gives this group of animals the sad title of the most endangered on the planet, followed by mammals (26.5% of endangered species), reptiles (21.4%) you see (12.9%).

Of the known species, the extinction of almost 200 has already been recorded. And these figures may be just the tip of the iceberg as these are poorly studied animals, many species are “invisible” in this evaluation because they are still to be discovered, warns in an interview with EFE one of the authors, the researcher at the Doñana Biological Station (Andalusia, south), Celsa Señaris.

But, What is behind this massive loss of amphibians? Researchers agree that the main threat is climate change.

While people can move or take certain measures in the face of the greater intensity and frequency of droughts, extreme heat, hurricanes or forest fires, amphibians do not have that capacity, they are “captives of the climate”, says Jennifer Luedtke, coordinator of the IUCN Red List of Amphibians working group, at a press conference.

To explain this “climate captivity”Señaris resorts to the nearby example of Doñana, where the largest lagoon in the marshes, Santa Olalla, has been practically dry for two years, leaving amphibians without an aquatic environment in which to reproduce.

“We are talking about animals with very short life cycles, which at most live 2 or 3 years, and not being able to reproduce in two years means that there is no replacement of new individuals, which leads to the collapse of populations and, with it, of the natural system where they live”, indicates the researcher at the Doñana-CSIC Biological Station.

The threats to amphibians bear great similarities to those of humans: in addition to climate change, their populations have already been decimated by a large “pandemic”and in the case of amphibians they are on their way to being devastated by a second one.

“The difference with Covid is that human mortality is around a small percentage of the world population and amphibian pandemics wipe out 100% of the lineages and there is no way to solve them with a vaccine”points out Señaris.

The first “covid” known to amphibians was the fungus “Batrachochytrium dendrobatidis”which since the late 90s was found to be the cause of massive mortality in frog populations around the world, including Spain, where it has brought the common midwife toad to the brink of extinction in Madrid, or the Balearic midwife toad ( islands, east).

The second “pandemic” It is caused by another deadly disease due to the fungus “Bsal” which is wiping out salamanders in Asia and Europe.

“It is a matter of time before it becomes the second known pandemic for amphibians”says Luedtke. Other threats such as habitat loss and degradation or pollution are added to this lethal cocktail.

Scientific projections for amphibians are not optimistic, and “Like canaries in coal mines, they are alerting us that environmental conditions can be harmful to life”highlights the CSIC researcher.

“Amphibians are indicators of the health of ecosystems, due to the sensitivity they have when the environment is altered, and they perform vital functions, such as the transfer of nutrients from aquatic to terrestrial environments or the control of insect pests,” adds another of the authors, Patricia Burrowes, a biologist at the University of Puerto Rico.

“Amphibians are predators of invertebrates and prey, their role is so important in the flow of nutrients in an ecosystem that, if they are missing, it is as if part of the threads of the fabric of a dress come off: the dress itself will be finished.” “washing away”exemplifies Señaris.

Precisely for this reason, researchers emphasize that protecting and conserving amphibian populations also means fighting against the loss of biodiversity and climate change.

They agree that we still have time to stop their loss. “It is not too late, this report provides the scientific information necessary to develop action plans to conserve amphibians, but we must act quickly, for the amphibians and for ourselves”concludes Burrowes.