In the cloud-touched highlands of Colombia's Sierra Nevada de Santa Marta, a community of frogs, toads and salamanders has so far escaped a fungus that has emptied amphibian populations across much of the Americas. Researchers who screened more than two thousand animals found no trace of it, a quiet mercy in a world where amphibians are already the most endangered vertebrates. Yet the disease has been detected only about twenty kilometers away, and the warm lowlands that have kept it at bay are a barrier that may not hold forever. The lesson the scientists draw is that the moment to act is now
Why Some Frogs Have Escaped the Amphibian Extinction, and How a Colombian Refuge Could Fall
The fungus is not a distant threat; it is close to the range.
Mark
Why does this one mountain range matter so much?
Mimi
Because it's intact. Elsewhere in the highlands of Central and South America the fungus has already wiped out much of the diversity. Here there are at least 48 species, and 25 exist nowhere else.
Mark
And the fungus isn't there yet?
Mimi
Not in the more than 2,000 frogs, toads and salamanders the team screened. But a highly virulent variant turned up about 20 kilometers away.
Luke
Let me press on "not there yet." Finding nothing in 2,000 animals is strong evidence, but it's a snapshot. The reporting doesn't say how often or over what period the sampling happened.
Mimi
Fair. What it does say is that the result held across a large sample, which is why the authors treat the range as a place to act before an outbreak.
Mark
What's been keeping the fungus out?
Mimi
Warm, dry lowlands, probably acting as a natural barrier.
Luke
Note the word "probably." That's the researchers' inference, not a demonstrated mechanism. And the prediction of massive losses is an expectation based on vulnerability and what happened elsewhere, not something observed here.
Mark
So how could the fungus get across?
Mimi
Through people: contaminated equipment, materials, or transported amphibians. That's why they want strict biosecurity and ongoing surveillance.
Luke
What we don't know is whether any such measures are currently in place, or who would enforce them. The study calls for them; the source doesn't say they exist.
Il Polso
- A virulent chytrid fungus has been detected just 20 km from a mountain range where not one of 2,000+ sampled frogs is infected.
- The region shelters at least 48 amphibian species, 25 found nowhere else on Earth, making any outbreak a potential extinction event.
- Warm, dry lowlands are the only natural wall between the pathogen and the range's most fragile species.
- Human carriers, such as contaminated gear, materials or transported amphibians, could breach that wall in a single step.
- Researchers urge strict biosecurity and urgent protection of vulnerable species before the fungus crosses the gap.
In the cloud-touched highlands of Colombia's Sierra Nevada de Santa Marta, a community of frogs, toads and salamanders has so far escaped a fungus that has emptied amphibian populations across much of the Americas. Researchers who screened more than two thousand animals found no trace of it, a quiet mercy in a world where amphibians are already the most endangered vertebrates. Yet the disease has been detected only about twenty kilometers away, and the warm lowlands that have kept it at bay are a barrier that may not hold forever. The lesson the scientists draw is that the moment to act is now, while the living chorus is still intact.
High in the Sierra Nevada de Santa Marta, an isolated mountain range in northern Colombia, the frogs are still singing. Across Central and South America, a killer fungus has already stripped away much of the amphibian diversity that once filled the highlands. This range has so far been spared, and it holds at least 48 amphibian species, 25 of which exist nowhere else on the planet.
A new study in Current Biology, led by researchers at Ghent University and Trier University, screened more than 2,000 frogs, toads and salamanders in the region. None carried the deadly fungus. The relief is tempered by a finding just 20 kilometers away: a highly virulent variant of the disease, close enough to the range to be a serious concern.
What has held it back is geography. The warm, dry lowlands act as a natural barrier, but the authors caution that this is not enough protection. Some of the region's unique species are highly vulnerable, and if the fungus arrives, massive losses are expected. The most likely route across the lowlands is human, through contaminated equipment, materials or transported animals.
The researchers see a rare window to protect an intact community before disaster strikes. They call for strict biosecurity, continued surveillance and urgent safeguards for the most at-risk species. The open question is whether those measures will be in place before the fungus finds its way over the 20 kilometers.
In the Sierra Nevada de Santa Marta, an isolated mountain range in northern Colombia, the frogs are still there. That is no small thing. Across the highlands of Central and South America, a killer fungus has stripped away much of the amphibian diversity that was once abundant. This range, so far, has been spared.
The community it holds is remarkable: at least 48 amphibian species, 25 of which are found nowhere else on the planet. It sits within a far larger crisis. Amphibians are the most threatened vertebrates on Earth, with 41% of species facing extinction.
A new study published in the journal Current Biology, led by researchers at Ghent University and Trier University, measures how close the danger has come. The team screened more than 2,000 frogs, toads and salamanders in the region and found no evidence of the deadly fungus in any of them.
But the clean result comes with a warning attached. Only about 20 kilometers (12 miles) away, the researchers detected a highly virulent variant of the disease. The fungus is not a distant threat; it is close to the range.
What has probably kept it out so far is geography. The warm, dry lowlands around the mountains appear to act as a natural barrier. The study suggests that barrier should not be taken as protection enough. Some of the region's unique amphibian species proved highly vulnerable to infection. If the fungus arrives, the authors expect massive losses of amphibian communities, as has been witnessed elsewhere.
The researchers describe the situation as a rare opportunity: a chance to protect an intact amphibian community before a devastating outbreak, rather than after. The most plausible route past the barrier is human. Contaminated equipment, materials or transported amphibians could carry the fungus across the lowlands that nature has not crossed.
For that reason, the authors say preventing introduction must be a conservation priority. They call for strict biosecurity, continued disease surveillance and urgent protection of the particularly vulnerable species. What to watch is whether those measures are in place before the fungus finds a way over the 20 kilometers.
Citazioni salienti
Preventing introduction of the fungus must be a conservation priority, requiring strict biosecurity, continued surveillance and urgent protection of vulnerable species.— Study authors, Current Biology
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