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Spotted salamanders breed in small woodland ponds, some of which dry up before the end of the summer. Photos by Emily Stone.
I’ve never been so glad to reach the top of St. Peter’s Dome. Even under heavy gray skies, the view from its high, rocky outcrop was spectacular. A forested mosaic in shades of green stretched all the way north to the shimmering strip of Chequamegon Bay on Lake Superior.
Hiking up, the tree canopy felt closed. But from above, the fuzzy white of emerging bigtooth aspen and the reddish tinge of young oak leaves hinted at a more precise phenology. Despite our recent warm days, it’s not quite summer.
It is, however, full-on bug season. I didn’t race to the top because of the view; I was chased there while seeking a stiff breeze and refuge from the biting hordes. I don’t hike much after the mosquitoes hatch, but on this day I had a special mission that was worth the blood loss.
It all started a few weeks ago, when I received an email from Jon Davenport, a biology professor at Appalachian State University in North Carolina. He and his students are studying the geographic variation in how spot-ted salamanders respond to pond drying during their larval stage. In a nutshell, do salamander babies in Louisiana grow faster as their pond gets shallower? How about in South Carolina? Massachusetts? What about in Wisconsin?
The students collected eggs in the southern part of spotted salamander’s habitat earlier this spring. Then, the pandemic hit. Their plan for a road trip to Wisconsin to sample spotted salamander eggs at the northwest limit of their range was derailed.
Jon got creative, and searched the iNaturalist database. I’ve written about this awesome resource previously – people post photos of plants and animals, other people confirm the identification, and then the observations are available for anyone to look at, including scientists. I’d posted a photo of spotted salamander eggs in 2016. And now here I was, on St. Peter’s Dome, with a backpack full of zip-top baggies and dozens of swelling mosquito bites.
Facing into the wind, I unfolded my BugJacket – still with its factory creases – and slipped this hooded shirt made of mosquito netting over my head. A sense of peace and goodwill descended with it. I bought the jacket for my sabbatical to Alaska and never needed it. Within 30 seconds of use on this day, it became an essential part of my hiking gear.
Now, having suited up, I abandoned the delicious breeze and began to hike down. Just below the summit is an old road bed, and off to its side is a small, round pool. Peering through the shimmering reflections of trees, I scanned the dark water for salamander eggs. Almost immediately, I caught site of one cluster; the dozens of embryos shimmering like pearls in their clutch of clear gel.
Spotted salamander egg masses are contained within a packet of gel, and often colonized by algae that provide them with oxygen.
Three more clusters appeared nearby, and with my search image primed, I walked slowly around the pond, spotting two more groups of egg masses. Most of the eggs were visibly green. Salamanders have a symbiotic relationship with algae. As with plants and animals everywhere, the two organisms exchange carbon dioxide, oxygen, and nitrogen to their mutual benefit.
During the course of 70 to 130 days, these eggs will hatch into tadpole-like larvae with an elaborately plumed collar of gills, and then lose those gills and leave the water as juvenile salamanders. They’ll seek winter refuge below the frost line, and return to breed in the same pond every spring for the next two-to-three decades.
The water was cool and the bottom of the pool slippery with leaves as I waded in up to my shins. Gently, I scooped one egg mass into each of four plastic baggies. Feeling their fragility, I was glad that I’d resisted the temptation to douse myself in bug spray that might have seeped through their porous protections. I double-bagged each one, and inflated the outer bags with air before sliding them gently into my backpack for the return journey.
Back at the parking lot, I arranged the four bags of eggs in a cooler, and padded them with bubble wrap. After taping on the cooler lid, I slid it into a cardboard box already equipped with a shipping label. Destination: North Carolina. The sun came out during my drive up to Ashland, and I got a close-up view of the water I’d seen from the top of the dome. Once the clerk at the service counter scanned the label, my job was done.
The box will arrive at Jon’s house in a day or two, and these eggs will join the experiment already in progress. In a modified walk-in cooler set to about 67 degrees F, with 12 hour day-night cycles, he’ll place four freshly hatched larvae in each of 12 five-gallon buckets. Strategically, he and the staff at the university’s animal research facility will remove water so that a third of the buckets will go dry after 60 days, a third will go dry after 80 days, and the rest will remain wet for 120 days. What the salamanders do is reliant on the genetic codes inherited from their parents. Some salamander larvae grow faster toward terrestrial, lung-breathing adulthood as their pond shrinks. Preliminary results show that the ones from Louisiana don’t.
Why does it matter? This is a baseline study, asking basic questions about salamander ecology. How do they interact with their environment? Next fall, Jon’s students will analyze the data, and begin to hypothesize again. What happens if climate change makes the salamanders’ pond dry up faster? Can some populations adapt? What do we do about the populations who can’t? A good research project will raise more questions than it answers.
In the meantime, Jon is thinking ahead. This adventure in community science and “remote sampling” has been fun for both of us, and easier on Jon’s budget, too. Maybe, with the increase in telecommuting, virtual events, and video meetings, scientific field research will shift toward remote work, too.
Now that I’ve discovered the Bug-Jacket, I’m excited and ready to help!
Emily’s second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at cablemuseum.org/books. Or order it from our friends at redberybooks.com to receive free shipping!
For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is currently closed due to COVID-19, but we’re still building our new exhibit and bringing you educational content. Connect with us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.