During warm, wet nights in early spring, thousands of amphibians shake off their winter grogginess and take to the roads. Hardy small mammals scamper along the forest floor and make extensive homes within the cracks of Acadia’s mountains. Some of the park’s smallest creatures, that play outsized roles in nature’s food web, are also some of its most mysterious. Learn about two survey projects asking what it’s like to take the pulse of Acadia National Park on Season 3 Episode 3 of Sea to Trees.

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TRANSCRIPT:

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Past, Present, and Future | Ferrying Frogs and Measuring Mice

In the summer of eighteen-eighty … a group of men who called themselves the Champlain Society took the pulse of Mount Desert Island. Not yet called Acadia National Park… the Harvard students documented and collected plants.. birds… and insects all across the island… trekking from its rocky shore lines to its sub-alpine peaks. They kept track of weather patterns like temperature… barometric pressure… and humidity. The Champlain Society’s notes and journals tell us how strong the island's pulse was one hundred and thirty six years ago.

In nineteen nineteen… Florence Bascom… the first female geologist to write about Mount Desert Island… took Acadia’s pulse in a different way. During Bascom’s time… the park was known as Lafayette National Park… but the geology was the same. She described the island as a region of superb natural charm and of no small physiographic and geologic interest. Bascom was awestruck by the deep valleys of Somes Sound and Echo Lake. She reconstructed the island's ancient past… illustrating just how long Acadia’s heart had been beating.

Today… thirty two inventory and monitoring networks dot the country. Their scientists traverse rugged landscapes and venture into distant locations to better understand the resources of our National Parks. They track wildlife… count vegetation… test water quality… measure soil health… and much more.

Past and present research are in constant dialogue. Specimens and observations collected by scientists a hundred years ago give a glimpse of a natural world different from the present. But what happens when there’s a gap… when a particular indicator is missing. When the doctor takes your pulse but not your blood oxygen. It means you aren’t getting a full picture… the full extent of your health. When we look under rocks but not on the roads… when we count the shrews but not the mice.

Sea to Trees is brought to you by Schoodic Institute at Acadia National Park. I’m Trevor Grandin. In this episode we’re getting hands on with frogs and mice. We’ll learn about two studies that are taking the pulse of amphibian and small mammal populations in Acadia and how their projects could help keep the park's heartbeat strong in a future that will not resemble the past.

Part one… frog and toad.

On a misty night in early May… Marisa Monroe and I… wide eyed and on alert…walked along Sieur De Monts road… scanning our headlamps from side to side and surrounded by the sound of spring peepers, searching for amphibians.

*frog noises and walking sounds*

Unsurprisingly… Marisa was the first to spot one of our slimy friends. She set down her clipboard and rolled up her sleeves. Instead of pointing it out right away she chided me to look a little closer.

{Monroe}: Do you see him? {Grandin}: Who? {Monroe}: Look closely! Find him. Keep looking. {Grandin}: Oh this little guy! He is blended in! *Laughing* {Monroe}: I know, he looks like a worm. These are hard to pick up. Hi! Oh my gosh, so beautiful. So I believe this is a… I believe it’s a red backed salamander. It’s a lead-phase, so it doesn’t actually have a red back… *fade*

This delightful salamander lives a dual life in Marisa’s mind – as a wonderful individual whose nightly routine includes basking on warm asphalt but also as one of hundreds of other salamanders whose presence on this specific road… on this specific night will provide valuable data in her research study that aims to protect them.

Marisa… an Acadia Science Fellow and graduate student at the University of Maine… is interested in the distribution and migration habits of Acadia’s amphibians. Along with her dedicated volunteers… she’s spent many of her nights in 2024… scouring the park’s roads… looking for some of its smallest and most porous creatures.

Many of the evenings start out in the same way… On a rainy night when the roads are saturated… volunteers throughout Acadia National Park descend upon their dedicated roadways… ready to tabulate toads.

*car door closing*

{Monroe}: We're wearing our safety vests, it's dark, it's in the park. There's really no streetlights out at these sites. So we put on our flashers, and we tried to stay really visible.

Flashlights and headlamps in tow… the volunteers write down site information on their data sheet like… date and start time…temperature… precipitation type… and road wetness

*writing on paper*

Then… the fun begins.

*helicopter noise* Like a search helicopter with a spotlight the volunteers start at the beginning of their stretch of road… marked by a small pink flag staked into the ground… and start to scan.

*walking and frog noises* {Monroe}: Here’s a spring peeper. Oop hello. Oop hello! We’ve got one here and do you know who this is? It’s an eastern newt. New species! {Grandin}: Oop, here we go! {Monroe}: Who’d ya see? Who’d ya see? Ooh! Hey, we’ve got a new species! Hello beautiful!

When an amphibian is found… the volunteer tallies it in the corresponding species box to indicate the number of individuals that were seen. After it’s been counted and appropriately fawned over… the volunteer will wet their hands and carefully ferry the amphibian to the side of the road it was facing.

Wet hands without any perfumes or moisturizers are best for picking up amphibians. Frogs… toads… and salamanders breathe through their skin and need to keep it wet to pull oxygen from the air. Skin products can transfer from the hands to the amphibian causing adverse reactions and trouble breathing. Vinyl and latex gloves carry the same risks of contamination. On top of chemical transfer… gloves could also dry out the amphibian's skin. Their sensitive respiratory systems is part of what makes them an important indicator species of wetland health.

{Monroe}: Sometimes it's not always clear which direction it wants to go. And if it looks like it can go by itself, we just let it sort of herd it over to the side of the road. And that's because we don't want to double count that amphibian as we come back from the other direction. And we also note any dead amphibians on the roads that have been run over by cars already that night.

Taking note of the dead amphibians on the roads is just as important as the live ones… because this project is more than a simple survey. It carries with it the hope to save these creatures from undue mortality. These frogs…salamanders… and toads are on the roads for two major reasons and both are explained by the animal’s life cycle. Time for a refresher!

*school bell ring*

The word amphibian comes from the ancient Greek roots amphi meaning double and bios meaning life.

Double life… an incredibly literal way to describe the journey of these slippery creatures. In the spring…toads and frogs wake up from their hibernations and lay their eggs in semi protected bodies of water… think ponds without predatory fish… freshwater wetlands… or seasonal vernal pools that fill up with spring rain or snow melt only to evaporate come summer.

Their eggs hatch and the tadpoles start life number one… in the water. They putter around with paddle shaped tails breathing through gills. Then… when the time comes… the juveniles leave their ponds and pools with newly grown arms and legs… making a mad dash to the forest where they will live out the majority of life number two.

Salamanders and newts can differ slightly from this order. Newts have an extra land stage called an eft… before they spend the rest of their adult lives back in the water they crawl around on land like an orange peel with legs. Some salamanders… like the red backed salamander… forgo the water entirely… preferring to lay their eggs inside fallen logs and under moist leaf litter.

So once again… what are all these amphibians doing on the roads? Being cold blooded creatures… they regulate their body temperature using the surrounding environment. Especially during the spring… when amphibians are waking up and thawing out… they need a quick way to get warm again.

Enter… asphalt. Even though the temperature may still be in the upper thirties… most roadways are exposed to sunlight throughout the day… absorbing and retaining its heat. As the sun sets and the air temperature drops… that heat in the pavement dissipates at a much slower rate… creating a natural warming pad perfect for amphibians to hunker down on.

Reason number two for their road affinity is explained through a more… reproductive lens.

{Monroe}: An amphibian might start in the forest like a spotted salamander. And then in the spring, they need to find each other and they need to be in an aquatic environment so they can lay their eggs and fertilize their eggs. So they often have to cross the road. And then, after they're done breeding and laying their eggs, they go back to the forest.

And then, while they are back in the forest their larval salamander, or if you're a frog or a tadpole, they're developing after they hatch from their eggs. And then in a few weeks, they have to leave the pond. And depending on where they want to go or need to go in order to forage for food, they might have to cross another road. So throughout the year, they're doing different things in order to survive and to grow up and to reproduce. And that puts them in conflict with roads often

So that