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Small boreal toads in the Maroon Bells-Snowmass Wilderness face big challenges

two hands in latex blue gloves holding a bumpy beauty: a boreal toad
Caroline Llanes
Aspen Public Radio
Boreal toads are not federally endangered but are endangered in Colorado. Biologists at the U.S. Forest Service and at Colorado Parks and Wildlife take data on toads in the field.

The human-caused climate crisis has caused rapidly rising temperatures throughout the West, drought conditions, and lower streamflows in rivers and creeks in Colorado.

And the Roaring Fork Valley is no exception.

These rapidly changing conditions are impacting our natural environment — from the largest organisms in the ecosystem to the very smallest.

And some of those smaller creatures, including boreal toads in the Maroon Bells-Snowmass Wilderness, are facing big problems.

Boreal toads are not easy to find along the most popular trails in the Maroon Bells-Snowmass Wilderness, such as the trails to Crater Lake or to Conundrum Hot Springs.

But if you know where to look, you can find some along the trail that runs up East Maroon Creek.

Finding the tiny toads in the creek itself is hard, for they prefer still water. Their ideal habitat is in ponds created by old beaver dams, particularly in the shallow areas.

Early June is the perfect time to look for toads in the Maroon Bells wilderness, because they can still be found where they spent their winters, and more recently, had their tadpoles.

two people stand in a large grassy field next to a pond formed by a beaver dam overlooked by snowcapped mountains
Caroline Llanes
Aspen Public Radio
Reed Paterson and Samantha Alford, both with the U.S. Forest service, look for toads in a beaver pond off East Maroon Creek.

But where do the toads go when the summer heats up?

“They disperse into the upland,” said Clay Ramey, a fisheries biologist for the U.S. Forest Service. “It’s highly likely they’ll go up and down these riparian corridors. But that dispersal is what makes for a metapopulation, you know, a population of populations. You need some to stray off to no man’s land because that’s how they populate the landscape.”

Ramey — joined by Samantha Alford, a seasonal Forest Service worker, and Reed Paterson, a student at Colorado Mesa University — went out in early June to catch some toads and get some information about them before they disperse.

Seasonal check-ins such as this are crucial to establishing the health of the toad population in the expansive Maroon Bells wilderness.

Last summer, some of these toads were discovered to have a potentially deadly fungus.

“Batrachochytrium dendrobatidis — but it’s most commonly referred to as BD,” said Jenn Logan, native aquatic species biologist for Colorado Parks and Wildlife’s northwest region.

She says BD is a problem for amphibians worldwide but only recently has become an issue for toads in the Maroon Bells wilderness.

“It impacts amphibians by infecting the keratin in skin, and it basically disrupts osmoregulation, and it causes the thickening of the skin,” Logan said. “And eventually this kind of leads to heart failure, and potentially death.”

The fungus is highly contagious, spreading with minimal contact.

So, in the field, biologists are careful with the toads they find in the beaver ponds along East Maroon Creek. Each toad is handled with a different pair of gloves and a different plastic baggie to get its measurements.

Alford, with the Forest Service, measures each toad from their snouts to their rear ends, or vents.

“Fifty-four millimeters,” she said.

A boreal toad is weighed in a plastic baggie hooked onto a scale
Caroline Llanes
Aspen Public Radio
Samantha Alford weighs a toad in a plastic bag as it attempts to escape.

And then she weighs them.

“Approximately 24 grams,” she said.

To weigh the toads, they are put into plastic baggies, which are then hooked onto a scale.

It’s an undignified process for the toads, who frequently try to escape.

Each toad also gets a photo taken of their belly — and some are more photogenic than others.

“I didn’t mean to throw you. … Would you just cooperate for a photo, please,” Alford tells a toad. “That’s like the hardest part, is holding these guys for a photo.”

Boreal toads have distinctive black-and-white markings on their bellies, like a fingerprint or QR code. The marking is how researchers at the Forest Service and CPW can identify individual toads.

The toads also get their bellies swabbed for the chytrid fungus.

a boreal toad gets its belly swabbed with a q-tip
Caroline Llanes
Aspen Public Radio
Reed Paterson swabs a toad’s belly. The swabs are preserved in ethanol and sent to a lab to test for BD, a potentially deadly fungus to amphibians.

The swabs will get sent to a lab to identify whether any of the toads are infected with BD.

The fungus was identified in some Maroon Bells toads last year, and researchers are hoping it hasn’t spread to all of the recorded spawning sites.

Some toads are more cooperative than others when it comes to swabbing.

“I am the toad whisperer, they’re quiet in my hands,” Alford said of one toad, which immediately began squeaking energetically.

“He heard you,” Ramey said.

The swabbing process is when the toads' sex is determined. Their squeaking sound is how male toads express themselves. Although female toads don’t make much noise, males make a very distinctive squeaking — something often triggered by belly rubs.

This toad-hunting day proved to be a banner one for the crews in the field. They found eight adult toads, plus dozens of juvenile toads no bigger than a thumbnail and thousands of tadpoles.

But the toad abundance is not the only thing they noticed: It’s really dry in both the beaver ponds and East Maroon Creek.

east maroon creek in the maroon bells-snowmass wilderness, surrounded by coniferous trees and mountains in the background
Caroline Llanes
Aspen Public Radio
East Maroon Creek, like many creeks, streams and rivers in Colorado, peaked early this year in its streamflow.

“It does not look high,” Ramey said. “It’s like summer flow."

Alford agreed: “This looks like the September water level.”

Like species in ecosystems throughout the West, boreal toads are facing the impacts of years of severe drought.

Streamflows in the Roaring Fork Valley peaked early this year.

That means that the beaver ponds that the toads call home during the winter and use to spawn their babies aren’t seeing as much water from the rivers and streams that feed them.

Ramey points out one of the warm, shallow pools inhabited by hundreds of black tadpoles.

hundreds of little black tadpoles in a puddle in the maroon bells wilderness
Caroline Llanes
Aspen Public Radio
Tadpoles congregate in shallow, warm puddles until they can metamorphose into toadlets.

“But see how already, like this little pothole isn’t wet to the perimeter,” he said. “It’s already half empty," Ramey said. "So we’re starting the summer on June 6, and it’s half empty already. So if these little things dry up before these little tadpoles metamorphose, it’s bad news for them.”

That’s a huge hit to toads in the wilderness, if they don’t have enough time for their tadpoles to metamorphose into toadlets. It could also mean reduced habitat for adult toads.

a juvenile toad attempts to escape a plastic bag
Caroline Llanes
Aspen Public Radio
This juvenile boreal toad — or toadlet — is still too young to definitively determine its sex. Ramey and the team take a rough count of the number of juveniles they see at the beaver ponds.

Logan, with CPW, says drought is only one piece of the picture.

She says the warmer temperatures seen throughout the region could also make prime toad territory attractive to other amphibian species from lower elevations, including chorus frogs and tiger salamanders. That can lead to competition, predation and, potentially, disease spread.

“They do coexist with toads in some areas, less frequently, I’d say, in the Maroon Bells than other places,” Logan said. “But they do increase odds of a toad population of a toad becoming infected with BD as they move up, you know, in elevation and into toad habitat.”

The health of toads in the Maroon Bells wilderness is critical. Toads are toads, of course, but Logan says they’re also canaries in the coal mine.

“As an amphibian, you know, they’re well known for being indicators of ecosystem health,” she said. “They’re both terrestrial and aquatic, so they sort of experience life in both words, which are also important to the overall health of the environment — that connection between water and land.”

That means keeping an eye on this boreal toad population is important, and the folks who monitor them need as much information as they can get, from surveys such as the one Ramey and the Forest Service did in June and from citizen scientists.

A researcher holds a boreal toad, who looks right at the camera with his beady little eyes
Caroline Llanes
Aspen Public Radio
Toads are indicator species, which means they can tell researchers a lot about the health of the environment.

So, if you’re in the wilderness and spot a toad, don’t try to pick it up and rub its belly to hear that magical toad song for yourself.

But feel free to call the Forest Service or Colorado Parks and Wildlife, and let them know where you saw it.

CORRECTION: A previous version of this story said warmer temperatures could make toad habitat attractive to other amphibian species from lower elevations, including forest frogs. That's not correct. The species in question is chorus frogs. A previous version also misspelled Reed Paterson's name as "Reid."

The story has been updated to reflect these changes.

Caroline Llanes is a general assignment reporter at Aspen Public Radio, covering local news and City of Aspen-based issues. Previously, she was an associate producer for WBUR’s Morning Edition in Boston.