Tracking An Alpine Frog That "Chuckles" And Beeps For Climate Change Research
Way up in the mountains of the Northwest you’ll find a little amphibian known as the Cascades Frog. This frog thrives in alpine wetlands, which are dependent on snowmelt. But snowpacks are decreasing across the West. And scientists are trying to figure out how the frogs will adapt to their shrinking habitat. And they’re using some pretty interesting research methods to do that.
Things are looking pretty dry at 5,000 feet elevation in Washington’s Olympic Mountains.
Ryan: “It’s actually dried out quite a bit this year. Usually the trail is running with water.
Maureen Ryan is looking for the wet spots. She’s a researcher with the University of Washington and an expert on amphibians that live at high elevation. We hike down a steep ridgeline, criss-crossing mountain goat tracks. We’re headed to Ryan’s “lab” – you might call it. She studies tiny snow-fed potholes of water, cupped in the folds of high mountain ranges in the Northwest – perfect habitat for cascades frogs.
Ryan: “This is one of the things we’re really concerned about is that these sorts of sites start drying early or drying at higher frequency and that can have really big effects on the biological community.”
Ryan is part of a group of amphibian researchers who have been studying the Cascades frogs in alpine wetlands of the Northwest for more than a decade. They’re trying to understand how the frogs use these ephemeral ponds, and how their survival and reproduction rates might change as the ponds start to disappear. You’ll only find the Cascades frog at high elevations in the Northwestern part of the U.S. , though they used to be common in Northern California as well. They’re a hardy species – adapted to withstanding nine months of the year beneath dozens of feet of snow. For a few short months in the summer the frogs come to warm sunny ponds - like this one - to feed and mate. And while they’re at it, they make what some describe as a “chuckling” sound. But we’ll get to that later. The team fans out, squelching through the muck and slowly scanning the water for the signature dappled brown and yellow heads of the frogs. Most of them are about the size of a child’s hand. Their bug eyes peer out at us from beneath the shelter of the banks.
Ryan: “Got a big female now.”
Now comes the crazy part. After the team has circled the pond and caught about 30 frogs, they pull out a device that looks like the scanner at the grocery store check out.
Ryan: "So what we have is a pit tag reader we just turned it on. And this is – just detects whether there’s a pit tag under the skin of the frog and if there is it gives us a number for that individual frog. Then we’ll know the history of that frog.”
The team has been inserting tiny magnetic tags, each about the size of a grain of rice, beneath the skin of these frogs for more than a decade. It doesn’t harm the frogs.
Ryan: “So we have some frogs that we’ve caught that we know are 13-14 years old and might be older. It’s pretty amazing.”
Along with their frog scanning, the team is monitoring the temperature and depths of ponds like this one. They want to find out when they’re drying up during the course of the summer. Then they can see how the changing water patterns are affecting the frogs’ survival, growth and reproduction from year to year.
Ryan: “Last year we had a good number of ponds where the ponds dried up before the tadpoles had metamorphosed so they didn’t survive there.”
Ryan worries that with less snowpack and hotter summers more egg sacks and tadpoles will be stranded as ponds dry out earlier in the season. That could ultimately decimate the population, unless they can move into deeper alpine lakes that are more resilient to the warming climate. The problem there is that many of those lakes have been stocked with trout for recreational fishing – and the trout find the Cascades frog delicious. We move on to sample several more ponds… We’re seeing lots of frogs, but I still haven’t heard the alleged “chuckling” call. At dusk we get back to the campsite and Maureen Ryan says we’re going to check out one more site, in the hopes of recording some chuckling. We hunker down in the heather by one snow-lined pond. The frogs are all around us, but they’re silent, just staring at us – like we’re unwelcome party crashers.
Ryan: “One on the rock, one in the grass. Two that are right under us and another one under the bank over there.”
Maureen Ryan tells me to hide, and she walks off to check another pond.
Then I wait, silently.
And then. They start.
Ryan: “What’s happening to these frogs is in no way dissimilar to what’s happening to us even if we can’t necessarily see it. These frogs are reliant on snowmelt for the water they need to live. For us, living in the west, most of the American west gets its water from snowmelt and that runs our agricultural system and our energy system. And so these ponds are kind of a microcosm of what’s going on in the west."
The Pacific Northwest has lost about fifty percent of its snowpack over the last 50 years. In the future, sounds like this could become even harder to record.
Copyright 2013 KUOW