Salamanders have a secret to surviving drought, heat waves and climate change
This story is part of Down to earth, a Vox reporting initiative on the science, politics and economics of the biodiversity crisis.
Ten years ago, a team of salamander researchers a dire prediction: that climate change would make much of the southern Appalachians, a hotspot of salamander diversity, inhospitable for many of these elegant amphibians. The most pessimistic models for the region predicted an “almost complete loss” of the entire group of salamanders they studied, known as plethodontids.
You would certainly expect moisture loving salamanders to be doomed in a warming up world. Across the United States, from North Dakota to Arizona, extreme droughts and heat waves suffocate the landscape, drying up wetlands, streams and other water sources essential for humans and wildlife. And bad news for salamanders is bad news for the rest of us: these creatures are vital to ecosystems as predators and prey, and scientists see them as barometers of ecosystem health.
Yet in recent years, the Slippery Salamander has proven to be remarkably resistant to heat, drought, and possibly even forest fires, thanks to a number of unique adaptations. They can essentially stop for months or even years, and a species can go through periods of drought in a protective mucus sheath. Salamanders teach scientists the power of adaptation and the limits of prediction.
To be clear, salamanders are not guaranteed a bright future. These petty crooks often like to stay hidden, making it difficult to collect good data – and a study from 2009 found “dramatic declines” in salamanders in Central America and Mexico. Meanwhile, more than 40 percent of North America’s more than 200 species are threatened with extinction, by some estimates. This worries researchers.
But what these striking adaptations show is that climate change is complicated – it will impact different animals in different and unexpected ways. Creatures that seem particularly sensitive, like salamanders, may be more resilient than we think, confusing our predictions of the impacts of climate change on different ecosystems. And in some cases, extreme conditions can trigger behaviors scientists haven’t noticed before.
To survive, salamanders do nothing
Salamanders look like lizards, which can survive in some of the world’s driest deserts, but the similarity isn’t even deep. While lizards have dry, scaly skin, salamanders generally need to keep their skin moist, and some spend their entire lives in water. As amphibians, they are cold-blooded, which means they cannot regulate their temperature internally. All of these characteristics make climate change a concern.
Again, Eric Riddell, a salamander expert who is now an assistant professor at Iowa State University, recalls questioning these predictions about the salamanders’ extinction. Salamanders have been around for millions of years, and sometimes the climate was hotter than today, Riddell told Vox. Certainly he and some colleagues reasoned, these animals have developed strategies to endure some of the conditions that global warming will trigger.
In the years that followed, Riddell and his colleagues tested their theory and found evidence to support it. Some salamanders, they discovered, have a remarkable ability to adapt their body to local conditions. When it’s hot and dry, for example, these amphibians can essentially stop – reducing the rate at which they burn energy and lose water, he said, to the point that they don’t ‘hardly need to eat or drink to survive. “They are very good at doing nothing,” said Riddell.
During droughts, Riddell suspects salamanders may take shelter below the ground where it is cooler and wetter – potentially for years – only to emerge when conditions improve. Researchers also claim that salamanders can resist wildfires using similar shelter strategies (although their tolerance seems to vary by habitat). In other words, they can just ride in bad environmental conditions, at least for a while.
Mucus cocoons and total transformation
There are other, weirder tricks that salamanders use to keep from drying out. Perhaps the most delicious thing is to wrap yourself in a cocoon made of mucus. (Who among us does not have feel like curling up in a cocoon of mucus at one point or another?)
This is the strategy of a type of salamander called the little mermaid. To prevent desiccation when its habitat (usually a pond) dries up, the salamander burrows in and secretes mucus from its skin, which hardens to form a “parchment“cocoon. The cocoon can prevent dehydration for” at least 35 weeks “or until the pond fills up again, according to one. study from 1972.
Red-spotted newts, also a type of salamander, take on a approaching in times of drought. As a rule, they have three life stages after emerging from an egg: larval, when they are aquatic; juvenile, when living on land; and adult, when they return to the water. But when their habitat dries up, they can actually transition to a terrestrial form for a fourth time, according to Steven Price, an associate professor at the University of Kentucky.
To make this movement, newts change the shape of their tail, the texture of their skin, and even their color. “It’s a really cool strategy for these animals,” Price said, and it helps them react to unpredictable weather changes.
What salamanders can teach us climate change
Taken together, these adaptations – especially flexibility around energy use and water loss – may help salamanders better withstand some of the effects of climate change, according to Riddell’s work. “By incorporating this flexibility into the forecast, we found that salamanders could maintain their ability to reproduce, even under one of the worst warming scenarios,” he said.
Does that mean these 2010 Salamander World’s End of the World projections are wrong?
The answer is probably yes, according to one of the scientists who first created them. “We are not seeing these predictions come true,” said Joseph Milanovich, lead author of the 2010 study and assistant professor at Loyola University in Chicago.
Milanovich spoke in the Smoky Mountains, where he was sample the salamander population. He has yet to release all the results, but for the record, he says that the populations and distributions of salamanders appear stable compared to the 2012 data. “The physiological tolerance of many of these species of salamanders is higher. than we thought ”, he said. “They are made for that.
There is, of course, a limit to what salamanders can tolerate, said William Peterman, another co-author of the 2010 study and associate professor at Ohio State University. A severe drought that spans years, for example, could cause serious damage to populations of salamanders, especially since many species need water to reproduce. (Some research previously reported that drought adversely affects larval aquatic salamanders.)
Likewise, more intense wildfires that burn extremely hot and over large areas – which are likely to become more frequent with climate change – could be a problem, according to Milanovich and Peterman. “When fires get really intense, they can burn off all the organic material” that the salamanders burrow into, Peterman said. “Where we’ve seen this happen, salamanders have all but disappeared from the landscape.”
It should also be noted that our climate is warming much faster today, due to human-made greenhouse gas emissions, than in the past – about 10 times faster compared to the mean warming over historical ice ages. This means that salamanders and other species of past eras have had much more time to adapt to the changes.
But in the end, the story of the salamanders may be good news, suggesting there are fewer threats to some. animals than previously thought. “Wildlife has the ability to cope with these conditions beyond what we understand,” said Jennifer Hunter, resident director of the Hastings Nature Reserve, a northern California field station that makes part of UC Berkeley.
Forest fires burned about a quarter of the Hastings last year reserve, which is 30 miles southeast of Monterey, but resident plant and animal life has quickly recovered, she said. “You immediately see some of these species that should really be struggling to escape – you know, small mammals, things like that – popping up really quickly,” she said. “We just think, ‘How did these little guys do? »» To a certain extent, nature can be very resilient.
As for salamanders, researchers hope these charismatic caterpillars persist, despite the rapidly changing environments around them. The question, says Riddell, is, “Where can they stand and for how long?”