Nature News: Skunk Cabbage generates heat in early spring to melt snow

published April 21 The Portsmouth Herald, Foster’s Daily, The York Weekly, etc.

Skunk cabbage leaves are huge!

Whenever I go into the woods this time of year,  I look for spring wildflowers to be in bloom.  There are a large variety of plants that take advantage of the scanty leaf canopy of early spring to grow and bloom quickly, before the trees leaf out.  Where I live in North Berwick we are behind most of the Seacoast region in terms of blooms–my garlic is barely up yet, the ponds by the river still have some ice every morning!!!  In search of wildflowers, I went for a walk (by myself)  at Great Works Regional Land Trust’s Rocky Hills Preserve last week and came upon one of the earliest wildflowers to bloom in New England-one of my favorite plants-skunk cabbage! This patch of skunk cabbage had been in bloom for awhile, I could tell this because in addition to the flowers the leaves were already out and gloriously unfolded into bright green skunky masses.  

It is only after the flowers are pollinated and begin to wilt that the leaves unfurl-this is how I knew pollination was long over-those huge cabbage-like leaves.  Early in the spring the skunk cabbage sends up a fleshy, highly-modified leaf forming that distinctive purplish hood. The scientific term for this is the spathe. Inside the spathe is a knoblike structure, a collection of tightly-packed flowers, called the spadix. Next time you see one, take a close look at the spadix.  The structure of the spathe is really interesting–the petals emerging from a jigsaw puzzle-like surface that looks, to me, like the carapace of a turtle.  

The spadix of a young skunk cabbage

In the spring, often before the ground begins to thaw, cells in the spadix start to respire, breaking down starches stored in the root at an alarming rate. This rapid respiration produces heat! Studies have shown that respiration rates in thermogenic (heat-producing) plants such as skunk cabbage often equal those of mammals of similar sizes. The hood acts as an insulator, trapping the heat generated by the spadix, creating a balmy little microclimate (usually a fairly consistent 60- 70 degrees) that can melt the surrounding snow. I love Craig Holdredge’s (from the Nature Institute) description of the air currents generated by this warmth: “Due to the warmth production, a constant circulation of air in and out of the spathe occurs. From the flower head, warmth is generated and the air moves up and outward, while cooler air is drawn into the spathe. A vortex is formed with air streaming along the sculpted, curved surfaces of the spathe. In a habitat with numerous skunk cabbages, a microcosm of flowing warmth and odiferous air is created in which the first insects of spring fly.” 

I have a large colony of false hellebore-a plant that looks somewhat similar to skunk cabbage and, as far as I know, inhabits the same kind of ecosystem–wet, marshy areas– growing along my river.  I wish I also had skunk cabbage, and wonder why they don’t grow there as well.  I have thought about trying to transplant some in, but it is usually a mistake to try to re-engineer an ecosystem.  I worry that the skunk cabbage might take over-much as I love them I don’t want them to crowd out the false hellebore (another plant with an amazing back story).  Skunk cabbages can form large colonies with extensive root systems that consist of a central rhizome that grows one or two feet into the ground with roots radiating out. The roots contract as they grow, pulling the plant down into the ground as it grows in the spring, keeping the stems and leaves at ground level. So the skunk cabbage, as a whole, grows downward every year, making it extremely difficult to remove. What’s more, these root systems and the colonies of skunk cabbage that erupt from them every spring can be hundreds to possibly thousands of years old!

If you can get outside, take a walk in the woods and look for spring wildflowers.  We are lucky enough to live in a place with 4 distinct seasons and are able to track the passage of time by immersing ourselves in the highlights of each season (trailing arbutus is flowering-a highlight, black flies are out in my neck of the woods–not a highlight!).  During this historic and stressful time it is more important than ever to get some green time if at all possible.  I would love to hear about what you are seeing out in the woods.  Please email me (spike3116@gmail.com ) or post sightings of signs of spring to my website www.pikes-hikes.com

Nature News: Wildflower Trillium is starting to bloom

published May 20, 2020 seacoastonline.com, the York Weekly, York County Coast Star, Portsmouth Herald and Foster’s Daily

One of the ways I have been dealing with staying at home is getting to know my backyard better through a daily ‘nature minute’ where I find something in my backyard, flora or fauna (though usually flora because plants don’t move) to do a short video about (you can find these at @pikeshikes).  I’ve gone through most of the obvious candidates; dandelions, unusual spring wildflowers, my first animal-a gray tree frog.  We have trillium starting to bloom along the bank that goes down to the river.  I can’t believe I thought this, but when I saw them I thought “why discuss trillium, everyone knows what they are, they probably have a boring backstory”.  What bothers me most about this is that I thought they might be boring. One of my guiding tenets is that nothing is boring unless you choose to be bored.  My other main tenet is that nature is awesome and wonderful.  So, I decided to read up on trillium.

Trillium are, indeed, a well-known wildflower.  As a spring ephemeral I would bet they are second only to lady’s slippers.   First, the name.  All trilliums are in the genus Trillium, which according to Merriam-Webster comes from New Latin and is an alteration of the Swedish word ‘trilling’ which means triplet.  This refers to the three parts of the flower, the three sepals directly behind the petals as well as three “leaves” which, technically, aren’t true leaves.  Those 3 big green things are a type of modified leaf known as a bract.  According to the US Forest Service “ Morphologically, trillium plants produce no true leaves or stems above ground. The “stem” is just an extension of the horizontal rhizome and produces tiny, scale-like leaves (cataphylls). The above-ground plant is technically a flowering scape, and the leaf-like structures are bracts subtending (underlying) the flower. Despite their morphological origins, the bracts have external and internal structure like a leaf, function in photosynthesis, and most authors refer to them as leaves.”

Since trillium are part of my backyard biodiversity study it made me inordinately happy to learn that the eastern United States has the highest trillium biodiversity in the world.  Of the forty three species of trillium (that we know of) found world-wide, thirty eight are found in North America! Four of these are native to New England: Trillium cernuum (whip-poor-will flower or nodding trillium), T. erectum (red trillium or stinking Benjamin), T. grandiflorum (great white trillium), and T. undulatum (painted trillium).  Other colorful common names for the trillium are wakerobin because they bloom with the first robins,  toadshade and birthroot due to traditional use during childbirth.

After taking a closer look at the trillium at my house I realized I have two different species, what I thought was just a big wilted one turned out to be nodding trillium, the white flower dangles, hidden, under the big, floppy, leaves.  Nodding trillium has the northernmost distribution of any of the North American trilliums.  Painted trillium have a more classic trillium look, flowers held above the bracts and easy to see.  One confusing thing about painted trillium is that their white flowers with a reddish or purplish blotch at the base can turn pink following pollination.  I only have three of these in flower, but can’t wait to see what happens.  

A friend just sent me a photo of a third native-red trillium.  I wish I had these at my house.  In addition to their colorful reddish flowers they attract pollinators in an unusual way.  They produce no nectar instead relying upon a fetid, rotten-meat smell that attracts flies (hence the common name stinking Benjamin). 

I know that I have a bit of a bias against big, showy, famous wildflowers-I tend to be drawn to the hidden, the not-so-obvious bits of nature that can take some effort to find.  But, after exploring the backstory of the trillium in my backyard I have a whole new appreciation of who they are.  As with everything in nature the more you learn the more you realize how little you know.  

Nature news: Building a magical mound in my garden

published May 12 2020 on seacoastonline.com and in the York Weekly, York County Coast Star, Portsmouth Herald, Foster’s Daily

I moved just a little more than a year ago and have been thinking about and building vegetable gardens ever since-many didn’t work out so well. The garden I started out back turned out to be in the coldest, shadiest part of the property. (I should have realized this based upon the amount of moss growing there.) So, this spring I moved the garden to the front — a sunnier spot that wasn’t originally my first choice given its proximity to the road. But I have grown accustomed to this. In this time of coronavirus, I now have almost as many neighbors walking by and waving hello as I do cars. It’s a friendly place for a garden.

Hugelkultur bed. The bricks are decorative, but the logs on either side are an extension of the buried logs underneath–they’ll slowly rot, retain water and add nutrients and organic material to the soil….they are building soil.

I am trying to garden as close to nature as possible — to work with nature, use nature as my guide and inspiration. My newest gardening adventure concerns something called hugelkultur, a word that means hill, or mound, culture. What I love most about it is that it is so obvious — its premise underlies natural soil formation. A tree falls in the forest, whether or not anyone hears it fall, it will eventually turn into soil. Hugelkultur beds use rotting logs as their base; the logs slowly release nutrients into the bed as they decay. So I recruited my son, quarantined back home, to help build a hugelkultur bed. He collected old logs from the forest, laid them on the ground and built a mound over them full of sticks (also from the forest), sod and straw, some compost, leaves and manure.

I was discussing my hugelkultur bed with my naturalist friend Steve Morello. He pointed out that there are more living cells in a dead tree than a living tree. In an article titled “Forest of the Living Dead,” Jenny Dauer of the Forestry Communications Group at Oregon State University asks, “Which is more alive: a live tree or a dead tree? If ‘alive’ means growing, breathing cells, a dead tree wins hands down. While only a thin layer of wood and bark are growing and actively transporting water and nutrients from roots to leaves in a live tree, all of a dead tree’s cells are teeming with insects, fungi, and bacteria. Some dead trees even have new plants and moss growing on them.”

Rotting wood is the basis of a healthy
forested ecosystem.

Walking in my woods this afternoon I thought about this — the sheer quantity of life found in one of those old standing snags or a downed log, slowly returning to dirt on the forest floor. It’s somewhat mind-blowing to realize that those snags and logs contain more life than the towering, living maples and hemlocks. Amazing to think that before that already partially-rotted standing dead tree hit the ground it was readying itself to release its nutrients back into the land, building soil.

The forest floor in my backyard is spongy with rot. Leaf litter and dead wood hide a vast network of lives dedicated to turning those dead leaves and wood into soil. Compare this to a typical garden bed. Most of my beds are wood frames filled with a mix of compost, manure and loam — very straightforward.

When I think of my hugelkultur bed, it seems magical in comparison — the logs buried in the bottom will start to decay over the next few years. The wood provides homes to the insects, bacteria and fungi that help with decomposition. It becomes spongy and holds onto moisture (a well-constructed hugelkultur bed needs to be watered only once every three weeks or so, at most). The decaying log provides warmth so that these beds can extend your planting season by a few weeks. What’s more, you are building soil with each mound you construct!

You can build hugelkultur beds in urban areas, a suburban backyard, even the desert. Try it! Bring a little nature into your backyard.

Nature News: The mating rituals of water striders

published May 6, 2020 seacoastonline.com, the York Weekly, Portsmouth Herald, Foster’s Daily and the York County Coast Star

The last time I wrote about water striders, it was the middle of the summer. I was sitting by a pond battling mosquitoes while watching them skate across the surface of the pond. I love how fast they move, which I didn’t understand. Are they skating and digging in their little feet for some purchase on the slick surface of the pond? Or is it a sticky surface that just looks like glass?

Water striders caught in the act of mating photo by Steve Morello stevemorello.com

Turns out not all small insects can do this – walk and skate on water. Water striders can because they have very fine hairs on the undersides of their legs that trap air and repel water. The scientific term for this is superhydrophobic. They can move so quickly because what they are doing is more like rowing, vigorously rowing, creating little swirls in the surface that help propel them forward. For their body size, they move fast, the equivalent of a 6-foot-tall person running 400 miles per hour!

I love the way their feet make little dimples in the surface of the water. Sometimes that’s how I first notice them – by the shadows those dimples cast on the bottom of the stream. As a biology teacher, I really love this, a textbook example of the high surface tension of water. They are bending the surface of the water.

I have been surprised to see water striders on my brook and along the edges of the river. I hadn’t realized they lived in flowing water as well as still water. Having never lived along a river until now, I have always made assumptions about who lives where. This was a big one. I always assumed they needed still-water, but there they were, skating upstream against the current, hanging out in the still water along the edges. And, as a wonderful sign of spring, this past weekend, while I was battling newly-hatched black flies instead of mosquitoes, I was able to catch some in the act of reproduction.

I realized these two were mating because they looked huge and on closer inspection it turned out I was seeing two, one being carried on the others’ back. So, I looked into water strider mating behavior. As you would expect, it is fascinating. As far as researchers know, there is no courtship involved. The male mounts the female. If she doesn’t fancy him, she might try to resist by deploying an extremely effective genital shield. However, the males have coevolved a behavior to prevent her from resisting, an extremely diabolical behavior. They coerce the female into mating by tapping out intricate patterns on the surface of the water. These patterns are meant to attract a predatory beetle that attacks from below the surface, the backswimmer. The female, since she is on the bottom, is more vulnerable to attack from below, so usually submits fairly quickly if the male starts tapping. This has been tested in an experiment (Han and Jablonski, “Male water striders attract predators to intimidate females into copulation,” Nature Communications, 2010) in which a small bar was glued to the back of the female. The bar raised the male up high enough that he couldn’t tap. When the male couldn’t tap, females resisted his advances for much longer periods of time.

I have been making more of a point than ever to get outside for some green time, to be in nature, to do some close and slow looking. By spending more time carefully observing water striders, my curiosity has been piqued and I have learned so much more than I would have with just casual observation. Look up slow looking. It’s something we shouldn’t have to be taught, but the art of sitting still in nature and observing what is going on around you is an art form, one that we can all participate in.

Frog and Salamander Egg Masses

published April 29 seacoastonline.com, The Portsmouth Herald, Foster’s Daily, the York Weekly and the York County Coast Star

Back in March, something wonderful happened. When nighttime temperatures hit the low 40′, when it was rainy and drizzly, huge numbers of amphibians began to move about, heading toward ponds to mate and lay eggs, most often to the vernal pools (temporary, fishless ponds) where they were hatched.

The two amphibians that participate in this annual early spring-late winter migration are wood frogs and spotted salamanders.

wood frog egg mass
Wood frog egg masses are loose clusters of eggs attached to a stick or branch at the surface. -Steve Morello photo

Wood frogs belong to a group of animals that have the remarkable ability to freeze but not die. To hibernate, they bury themselves in the ground and go into a deep hibernation in which their hearts stop beating, they stop breathing and partially freeze. Then with warm (above 40 degrees F) spring rains they revive, dig themselves out of the ground and head to the water to mate.

Spotted salamanders don’t carry things this far, but they do hibernate in underground burrows and tunnels, also emerging in the spring.

So, this magical thing happened (referred to as “Big Night” by wood frog and spotted salamander aficionados). These hardy amphibians came out of hibernation and headed to their ancestral pools to reproduce. Once they finished mating and laying eggs, they headed back to the woods to lead a very terrestrial existence for the rest of the year. Now, what remains in those pools are their egg masses.

So, now is a good time to check out your local vernal pools to see if you can find frog and salamander egg masses. The egg masses are big and have characteristic features that make it relatively easy to distinguish wood frog from spotted salamander eggs. Almost always the eggs are laid in vernal pools because, due to their temporary nature (vernal pools dry out in late summer and early fall), they are fishless. Fish would love to chow down on those huge egg masses. They are so easy to see.

Once you know what to look for, it is relatively easy to tell a spotted salamander egg mass from a wood frog egg mass; spotted salamander egg masses are surrounded by a jelly coat, wood frog egg masses are not.

If you were to pick up a spotted salamander egg mass (which you really shouldn’t), it would hold together and you would see that in addition to the gel surrounding each egg, there was a thick gel surrounding the entire mass.

If you were to pick up a wood frog egg mass (which you really shouldn’t), it would be looser and would fall apart more easily. The surface would look like a cluster of grapes. Each individual egg has its own gel-coat, but the entire mass lacks the extra protection of that outer layer.

Both wood frogs and spotted salamanders attach their eggs to vegetation (though sometimes spotted salamander eggs will rest on the bottom). Wood frog egg masses tend to be attached to overhanging vegetation or to twigs at the surface, whereas spotted salamander egg masses are attached to deeper branches, below the surface of the water. One interesting variation you might see with spotted salamander egg masses. Some have a clear gel-coat while the gel-coat of others is milky-white. The significance of this difference is unclear, but some research suggests it might confer some protection from predation.

Both wood frogs and spotted salamanders are considered to be obligate breeders in vernal pools, meaning they rely upon vernal pools for reproduction. The Seacoast area has an extremely high density of vernal pools, a habitat type threatened by suburban sprawl. If you know of a vernal pool in your area, try to protect it. These little amphibians have been using these pools long before we were here. They are also extremely important members of our forest ecosystems. They are food for an enormous number of predators – snakes, herons, raccoons, skunks and mink, to name a few.

To me, their migration to vernal pools to lay eggs is one of the most lovely of our signs of spring and each year. I seek those eggs out as a reminder of all the mysterious goings-on in my backyard.

Skunk Cabbage in Spring

skunk cabbage

Whenever I go into the woods this time of year, I look for spring wildflowers to be in bloom. There are a large variety of plants that take advantage of the scanty leaf canopy of early spring to grow and bloom quickly, before the trees leaf out. Where I live in North Berwick we are behind most of the Seacoast region in terms of blooms– my garlic is barely up yet, the ponds by the river still have some ice every morning!!!


In search of wildflowers, I went for a walk (by myself) at Great Works Regional Land Trust’s Rocky Hills Preserve last week and came upon one of the earliest wildflowers to bloom in New England-one of my favorite plants-skunk cabbage! This patch of skunk cabbage had been in bloom for awhile, I could tell this because in addition to the flowers the leaves were already out and gloriously unfolded into bright green skunky masses.

It is only after the flowers are pollinated and begin to wilt that the leaves unfurl-this is how I knew pollination was long over-those huge cabbage-like leaves. Early in the spring the skunk cabbage sends up a fleshy, highly-modified leaf forming that distinctive purplish hood. The scientific term for this is the spathe. Inside the spathe is a knoblike structure, a collection of tightly-packed flowers, called the spadix. Next time you see one, take a close look at the spadix. The structure of the spathe is really interesting–the petals emerging from a jigsaw puzzle-like surface that looks, to me, like the carapace of a turtle.

skunk cabbage spadix and spathe
Close up of spadix-this contains the flowers of the skunk cabbage-each of those little frilly bumps is a flower.


In the spring, often before the ground begins to thaw, cells in the spadix start to respire, breaking down starches stored in the root at an alarming rate. This rapid respiration produces heat! Studies have shown that respiration rates in thermogenic (heat-producing) plants such as skunk cabbage often equal those of mammals of similar sizes. The hood acts as an insulator, trapping the heat generated by the spadix, creating a balmy little microclimate (usually a fairly consistent 60- 70 degrees) that can melt the surrounding snow. I love Craig Holdredge’s (from the Nature Institute) description of the air currents generated by this warmth: “Due to the warmth production, a constant circulation of air in and out of the spathe occurs. From the flower head, warmth is generated and the air moves up and outward, while cooler air is drawn into the spathe. A vortex is formed with air streaming along the sculpted, curved surfaces of the spathe. In a habitat with numerous skunk cabbages, a microcosm of flowing warmth and odiferous air is created in which the first insects of spring fly.”


I have a large colony of false hellebore-a plant that looks somewhat similar to skunk cabbage and, as far as I know, inhabits the same kind of ecosystem–wet, marshy areas– growing along my river. I wish I also had skunk cabbage, and wonder why they don’t grow there as well. I have thought about trying to transplant some in, but it is usually a mistake to try to re-engineer an ecosystem. I worry that the skunk cabbage might take over-much as I love them I don’t want them to crowd out the false hellebore (another plant with an amazing back story). Skunk cabbages can form large colonies with extensive root systems that consist of a central rhizome that grows one or two feet into the ground with roots radiating out. The roots contract as they grow, pulling the plant down into the ground as it grows in the spring, keeping the stems and leaves at ground level. So the skunk cabbage, as a whole, grows downward every year, making it extremely difficult to remove. What’s more, these root systems and the colonies of skunk cabbage that erupt from them every spring can be hundreds to possibly thousands of years old!


If you can get outside, take a walk in the woods and look for spring wildflowers. We
are lucky enough to live in a place with 4 distinct seasons and are able to track the
passage of time by immersing ourselves in the highlights of each season (trailing
arbutus is flowering-a highlight, black flies are out in my neck of the woods–not a
highlight!). During this historic and stressful time it is more important than ever to get
some green time if at all possible.

Signs of Spring

My goal with this post is to track signs of spring in the Southern Maine/Seacoast area. Anyone who wants to contribute, please do. Upload sightings and photos to the comments and I will add them to this list. I plan to organize by date but will also include general locations so I can get a sense of where these sightings are happening relative to my location (North Berwick, Maine).

Skunk Cabbage at the south end of York Pond, Rocky Hills Preserve, Eliot ME. 4/17/20 Note the purple spathes of the flowers at the base of the leaves.
This is a close up of the spadix–the flower of the skunk cabbage. You can see parts of the flower sticking out from the pulpy jigsaw-like complex of the spadix.
American Wintergreen Pyrola americana 4/17/20 Stubbs Marsh North Berwick
Downy rattlesnake plantain Goodyera pubescens 4/17/20 Stubbs Marsh North Berwick ME
Red Maple flowers Acer rubrum 4/18/20 Little River North Berwick
Trailing arbutus Epigaea repens Rocky Hills Preserve Eliot ME 4/17/20

Ice is Magic

published Feb 5, 2020 in the York Weekly, Portsmouth Herald and Foster’s Daily and online at seacoastonline.com

I spent almost the entire first semester last year having my freshmen STEM class run experiments about ice. Every morning, when I walk my dog, we follow a path along the river and observe the ice, marvel at the huge slabs of ice that are carried downstream and stacked like pancakes in some places, crunch our way over the paper-thin ice that coated the hummocks of the floodplain after the last brief thaw, watch dangling orbs of ice form in the waterfall that spills down to feed the river. I, like so many others, am obsessed with ice.

If you think about it, ice formation on a pond or lake is fairly straightforward. As the water gets colder, it gets denser and starts to sink. Liquid water reaches its maximum density at 4 °C (39.2 °F), after that it continues to get colder and freeze solid, but as it freezes, it becomes less dense and floats to the surface and we end up with ice-covered lakes.

Ice slabs pile up in Little River

At first, the ice is paper-thin, fragile sheets that crumble in your hand. As winter’s cold progresses, the ice gets thicker and thicker as more ice is added from the bottom. As long as the pond or lake is deep enough, there should always be at least some liquid water underneath the ice. This is very helpful to the animals that live in the pond or lake. They can survive in the liquid water near the bottom until the spring thaw.

Now, think about a river or stream in which the water is constantly moving. All of that turbulence makes it difficult for a nice sheet of ice to form. On cold winter nights, the surface water of a river cools, crystals of ice form and start to grow. The constant water movement keeps the crystals from growing together into a solid sheet, instead you get a slushy mixture of water and ice called frazil ice. You can see this floating on the top of a river in early winter, or instead of floating on top, because the crystals are so small, they can easily be carried by the turbulence down to the bottom of the river.

Ice slab close-up with river behind it

As temperatures continue to drop, the frazil ice can start to join together at the surface and form round plates of ice with upturned edges (from the plates bumping together). This is called pancake ice. Or, what was more common on my river, ice will start to form along the edges of the river. Ice forms more easily along the edges because there is typically less water movement and the temperature of the shallow water on the edge cools faster. This is called border or shore ice. Border ice will generally enlarge toward the middle of the river until the ice from both sides meet.

Border ice forms along a small stream

Another interesting way a river can freeze is when the frazil ice that is transported to the bottom of the river attaches to the streambed and builds from the bottom up. This is called anchor ice. Anchor ice can grow very rapidly and block the flow of a river or stream causing local flooding. If there is particularly low flow of water along the bottom, an enormous amount of anchor ice can build up. This can be extremely harmful to aquatic life because the anchor ice can physically lift up parts of the streambed and move it downstream, movement akin to the action of a bulldozer, killing small fish and aquatic invertebrates (like dragonfly or caddisfly larvae) that live in the streambed, or freezing fish eggs that were waiting for spring to hatch.

I thought I first fell in love with ice in some dramatic location, perhaps when I crossed Lake Champlain on the ferry one cold winter’s night and watched the prow cut through the ice and listened to it grind against the hull of the boat, or when I was travelling as a National Geographic Grosvenor Teacher Fellow in the Arctic Ocean and witnessed firsthand the ethereal beauty of icebergs and the vast expanses of pack ice in the polar sea. But watching the beautiful, ever-mutable ice along my little river this winter has made me realize that I’ve loved ice since I was a kid watching icicles dangle from the gutters of my house, that no matter where you find it, ice is magic.

Join the soft-shell clam recruitment network

published January 29, 2020 in The York Weekly, Portsmouth Herald and Foster’s Daily and online at seacoastonline.com titled ‘Nature News’

Clam recruitment boxes will be placed on clam flats in Wells Maine this spring Brian Beal photo

Dr. Brian Beal, Director of Research for the University of Maine at Machais Downeast Institute (DEI)-the easternmost marine research laboratory in the entire United States – gave a talk a week or so ago up in Wells about a research project that will start this spring all along the coast of Maine. The main focuses of the DEI all have to do with shellfish, primarily clams.

Brian was down in Wells explaining why large wooden boxes would be appearing on some clam flats in Maine, from Wells north to Sipayik, this spring and summer. The boxes are part of a study aimed at understanding how best to protect young soft-shell clams at a critical time in their development-when they are transiting from a water-born planktonic life to settling into the mud and sand flats and growing into delicious steamers. 

The clam recruitment boxes appear to provide a safe place for juvenile planktonic clams to settle Brian Beal Photo

Protecting soft shell clams from what? Primarily the invasive European green crab (Carcinus maenas).  Green crabs were introduced to New England back in the early 1800s by travelling in the ballast of ships carrying cargo from Europe to the United States.  Since then they have travelled up the East Coast, decimating the soft shell clam industry and have more recently (the late 1980s) reached the West Coast where they are wreaking similar havoc from San Francisco up to Seattle.  One reason green crabs are such a problem is that, unlike our native crabs, green crabs can swim out onto the mudflats to hunt. Our native rock and Jonah crabs don’t do this-they can’t swim and can’t get out and back to the mud flats as the tides ebb and flow..  Adult green crabs swim out to the mud flats at high tide, grab the soft-shell clam siphons (the fleshy clam ‘necks’), pull them out and eat them. Our soft-shell clams have adapted to this by digging deeper into the mud so that they can escape. However, a probably bigger problem is that young green crabs  (-perhaps a couple millimeters in size) also settle on the mudflats and prey upon anything smaller than themselves-juicy morsels like young soft-shell clams. 

To understand how the recruitment boxes work you have to know a little bit about a clam’s life cycle.  Before I joined the Wells Clam Conservation Commission almost a decade ago, I hadn’t understood how complex that life cycle is and how threatened it is by the invasive green crab. 

The life of a soft-shell clam (Mya arenaria) begins on a warm spring day when both male and female clams release their sperm and eggs into the water, if the two should meet-fertilization occurs.  This is called broadcast spawning and time is everything. The young that develop from this union are planktonic, they don’t look much like adult clams, instead they look like tiny blobs with tufts of fine cilia that they use to swim through the water.  These larval forms are called trocophore larvae that then mature into veliger larvae. The veligers look like a shell-less swimming clam. These baby clams come to intertidal flats via the water column. They swim for 2-3 weeks depending on seawater temperature and location along the coast, and then settle to the flats.  They are about the size of a grain of sand. This is when they are most vulnerable to predation. Here is where the recruitment boxes come in.  

Recently settled clams are at most danger from juvenile green crabs Brian Beal photos

Recruitment boxes are large wooden boxes with mesh on both the top and bottom.  Planktonic clams that settle into these boxes appear able to have much higher survival rates than those settling on the unprotected mud or sand flat.  

Mesh on both top and bottom of the boxes protects young clams from many predators Brian Beal photo

Why put out recruitment boxes? Soft-shell clam landings across Maine have declined by 45% since 2001, and few seem to be aware of this. An interesting tie-in with climate change appears to be that warmer sea surface temperatures (as we have been seeing in the Gulf of Maine) encourage explosive growth of green crabs.  Brian’s project aims to increase public awareness of what is occurring within this iconic fishery and create a statewide data set for fisheries managers in the Department of Marine Resources, and for other fisheries scientists, to better understand factors that affect the health and well-being of the soft-shell clam fishery.  

Whether you live in Maine or New Hampshire, if you want to get involved in this ‘recruitment network’ contact Brian at the Downeast Institute.  Dr Beal is looking forward to working with clammers, clam conservation committees, elected officials, schools and students in each community to learn about the early life-history of clams and what may be regulating or controlling their numbers.  Ultimately, he would like to create a network where the coastal communities that are part of this first trial are a subset of a larger group of communities all doing similar work that may play an important role in how soft-shell clams are managed.

In winter’s cold, the subnivean zone is abuzz

Published January 21 2020 The York Weekly, Portsmouth Herald and Foster’s Daily and at seacoastonline.com Titled ‘Nature News’

The subnivean zone lies between the snow and the earth.

This winter has been troublesome; a few weeks ago it was so cold my pipes froze, then it we climbed to unseasonably warm temperatures, then some more snow, and now, very cold again-my pipes continue to freeze. One thing that makes me happy is that we have a nice layer of snow on the ground, insulation that is is vital to the survival of many of the plants and small mammals, even microscopic life forms, that are essential parts of our Northern ecosystem. So, for many, the recent snow was welcome relief from the cold.

While the surface seems empty, underneath, at the interface between ground and snow, a veritable city is rising. Old leaves and branches hold the snow up, creating an open space. The ground also radiates heat, warming the overlying snow, which instead of melting sublimates (when a solid turns into a gas without first becoming a liquid) directly into water vapor. Both of these processes leave a space between the snow and the ground, called the subnivean zone.

The word “subnivean” comes from the Latin for under (sub) the snow (nivean) and is a scientific term referring to the open passageways that form under deep snow.

Six or more inches of snow are all that are needed to trap the earth’s heat and allow a subnivean zone to form. This zone remains humid because of the transformation of snow into moist water vapor and is capped by a layer of ice that acts as an insulating roof. The temperature of the subnivean zone is generally a constant 32 degrees, protecting species that would otherwise freeze.

The most common inhabitants of the subnivean are mice and voles — they make tunnels under the snow connecting sleeping areas and sources of food. Red squirrels also burrow into the subnivean to stash food. Entrance holes to these networks allow carbon dioxide to escape. Carbon dioxide is released when these animals breathe and by the ground itself. Without the entrance holes to serve as ventilation shafts, carbon dioxide could build up to lethal levels.

While the subnivean zone provides protection for mice and voles, it is also the hunting ground for the short-tailed weasel (or ermine), a weasel that, except for its black-tipped tail, turns snowy white in the winter. This small weasel, just the right size to live and hunt in the tunnels under the snow, is a major predator upon small rodents.

All you need is about 6 inches of snow to allow the subnivean space to form

Recent research has unearthed a whole new category of inhabitants of the subnivean zone — microbes that are proving to be important players in the cycling of both nitrogen and carbon dioxide between the earth and the atmosphere. A deep snowpack with an active subnivean zone appears to encourage a healthy microbial population that, through respiration, releases significant amounts of carbon dioxide into the atmosphere. Studies suggest that as much as half of the carbon taken up by plants in the summer is released back into the atmosphere by microbes in winter (Paul Brooks, University of Colorado Boulder). At the same time these microbes, by processing and storing nitrogen, fertilize the soil as the snow melts.

Without a healthy snowpack, without these snowpack microbes, plants don’t do as well come spring. While these microbes may be releasing a lot of carbon into the atmosphere during the winter, they are also necessary for healthy plant growth — plants that will absorb carbon dioxide throughout the growing season.

For all these reasons, it seems to me, a nice deep snow, serving as an insulating blanket on the earth, is a welcome part of our northern winter.