Natural Destinations: Dead Creek Wildlife Management Area

by Cathy Bell

(originally posted on vtdigger.org)

Every autumn, thousands of snow geese take a break from their 5,000 mile southbound migration to rest and feed at Dead Creek Wildlife Management Area in Addison, Vermont.  Journeying from their breeding grounds on the Arctic tundra to their winter range in the mid-Atlantic and southeastern states, the snow geese are but fleeting visitors to the Green Mountain State, descending on our cornfields from October into early November.

The bright white feathers of a snow goose’s body contrast with tips of the wings, which look as though they have been dipped in paint of the richest black.  Young birds are brushed with gray on their backs, giving them a dirty appearance.  Here and there among the flocks are dark gray individuals with white faces.  These steely-looking birds, commonly known as “blue geese,” are the same species as the white ones.  Snow geese of either coloration are far prettier, to my eye, than our resident Canada geese.  Getting to see these visitors from the north is a seasonal treat.

Snow geese

Snow geese at Dead Creek

Hoping to find some snow geese, I went to Dead Creek on Saturday, October 30.  The day started out sunny but clouded up as the big Halloween nor’easter worked its way towards New England.  Driving down Route 22A from the north, I made a right turn onto Route 17.  I had gone less than a mile from Addison Four Corners when I saw a wheeling flock of waterfowl.  Backlit, the winged forms did not reveal any details of their plumage, but the size and flight pattern didn’t seem quite right for Canada geese.  Even as I thought to myself that I must be in the right place, I saw a turnoff on the south side of the road.  I pulled off the highway, shut off the ignition, and hopped out of the car, binoculars in hand.  Looking to the south, I felt my jaw drop in wonder.

About 800 geese were in a field very close by, in easy sight of a viewing platform with interpretive signs.  Hundreds more were in a distant depression.  From the knot of people with binoculars and spotting scopes a quarter mile to the west, I guessed there was another—possibly even bigger—group of geese over there too.  Aerial photo counts that weekend documented more than 4,600 geese in the area, but few people braved the chill wind of the gray afternoon to witness the impressive spectacle.

A northern harrier, its white rump patch catching the watery light, startled the nearest geese into rising from where they rested and fed.  Within moments, the nervousness of a few waterfowl swept through the flock, and hundreds of birds were in the air, honking their discontent in a higher-pitched and more tremulous voice than that of the familiar Canada goose.

Though I looked carefully, I failed to find any Ross’s geese among the swirling clouds of white waterfowl.  Snow geese and Ross’s geese are two distinct species, though very similar in appearance; the rarer Ross’s is more diminutive in build and has a smaller bill.  I later read on the Vermont bird listserv that there were indeed two Ross’s geese at Dead Creek that afternoon, but they were the needles in the haystack of thousands of snow geese.

I may have lucked into witnessing the peak of this year’s snow goose migration, but there’s still time for you to see the spectacular waterfowl as they pass through Vermont.

At 2,858 acres, Dead Creek Wildlife Management Area is administered by Vermont Fish and Wildlife and includes extensive reaches of cattail marsh and stretches of open water.  The geese, however, are concentrated in upland agricultural fields.  The designated goose viewing area along Route 17 is the best place to see the birds, but a little farther south, Gage Road can provide good sightings as well.

Moreover, though the snow geese may be the star attraction, there is more here for inquisitive visitors to enjoy.  Northern shovelers and green-winged teal dabble in the shallow, ponded water of the fields, and once in a while a pectoral sandpiper passes by overhead.  A quarter mile west of the goose viewing turnoff, Route 17 crosses the still, murky waters of Dead Creek.  Mallards and black ducks ply the waters here.  Just over the bridge, a left turn takes you down a gravel road towards a hunters’ camping area.  Look along the reedy edges of the water for great blue herons and wood ducks.  Despite its name, Dead Creek is a lively place.

The creek flows northward, parallel to the southernmost portion of Lake Champlain.  Just seven miles north of where it flows under Route 17, the creek joins with Otter Creek and soon wends its way into the lake.  Its meandering path has been modified by the addition of dams, and today, the state actively manages water levels in the flooded impoundments.

The snow goose hunting season runs from October 1 – December 29 in the Lake Champlain waterfowl hunting zone, with a daily bag limit of 25 birds.  Portions of the Dead Creek Wildlife Management Area, including the upland areas south of Route 17 near the viewing area, are managed as a refuge where no hunting or other public access is permitted.

More information, including maps and directions, is available from Audubon Vermont and Vermont Fish and Wildlife.

Young Scientists Plot for Smart Urban Forestry

by Liz Brownlee

“Wait until you see the accuracy of our plot,” calls the lab team.

The four undergraduates burst with pride, oblivious to the prickling raspberries and thick brush that edge the Intervale forest.

They stop me midstride.  As their lab teacher, I’m fully equipped with aerial maps, GPS, first aid kit, phone, and extra rain gear.  I’m planning to cruise through this pasture towards the soybeans and into the swampy forest.  My goal is to check in with teams at twelve more study plots, spread over the 350 acres of forest and fields.

This lab project is a real, on-the-ground application of their natural resource training.  Most weeks these first-year students learn the basics of field work in big, broad fields (fisheries, stream ecology, forestry, etc.). The field data they record in their weekly labs is important: they use it to learn how to create papers, reports, and essays.

This week, though, the data is headed to city hall.  We’re studying the Burlington urban forest to help the city make informed decisions about valuing and managing the forest.

I need to check in with the next group. It’s incredibly important that the teams describe each plot with accuracy and efficiency.  I know that all the teams are anxious to prove their worth, to share their budding knowledge and field skills.  But this team’s stories cannot wait.

Elliot, a bright-eyed skier from Utah starts first.

The maple we used to mark our plot was so big, our measuring tape couldn’t reach around it, he says.

Aptly named and observant, Hunter chimes in.

There was a deer trail, but that’s it – otherwise it’s untouched.

Eric, a tattooed, intelligent former Marine, knows this isn’t entirely true.

How should we record the land use on this plot, Liz? This isn’t a park, and it’s on the farm but not cultivated land.

We brainstorm the forest’s values: recreation and flood control top the list.

I change my route, unable to leave the pull of their enthusiasm.  Elliot fires questions as we walk the farm’s puddle-filled gravel road.

We didn’t see any sign of invasive species like emerald ash borer – that’s good, right?  And the ground was covered in mud from the hurricane and the flood – do you think the forest will rebound before teams come next year?

The team answers most of their questions before I can chime in, and I know that I’m no longer needed.  I head for the next site when Carly, another lab teacher with twenty more students, calls from the Old North End of Burlington.  We check in, cars honking in the background on her end.

Over two hundred UVM students are taking the pulse of the forest, from tree height and canopy dieback to ground cover and plant-able space. They’re studying over one hundred plots throughout the city, and all in just two weeks.  We’ll crunch the numbers with a program called iTree that’s being used worldwide.  The city will use the results to decide where and what to plant next, and how to properly value a forest that cools homes, mitigates pollution, and absorbs storm water runoff.

They’ve tracked changes in the forest’s health.  They’ve built confidence as budding natural resource scientists.  And next year, two hundred new students will do it all again.

Enough Pumpkins in the Patch?

by Cathy Bell

(originally posted on vtdigger.org)

Back in the middle of September, a headline caught my eye. “Northeast Faces Devastating Pumpkin Shortage,” I read, with a mixture of amusement and trepidation.

Devastating?  Really?  Pumpkins are cheery and plump and orange.  It’s tough for me to take them seriously enough to believe that anyone could possibly construe a shortage as devastating.  Even the name—pumpkin—is irresistibly rotund and bouncy-sounding.  Still, that headline got me a little worried.  I have a tradition of throwing a pumpkin-carving party the weekend before Halloween.  It’s always great fun to gather a group of friends together for a few hours of quality time with sharp knives and slimy pumpkin innards.  What if there weren’t enough pumpkins this year?

Fortunately for pumpkin seekers, it appears that the forecast Great Pumpkin Shortage isn’t so devastating after all.  If you drive through rural Vermont or stop by your local farmers’ market, you will see row upon row of happy-looking pumpkins offered up for sale.  So what’s the story?  Is there a pumpkin shortage or not?

To answer that question, I swung by my local farmers’ market in the Old North End of Burlington and checked in with Lauri Brewster of The Farm at Cold Spring in Milton.  “It’s regional,” said Brewster.  “Low-lying areas got hit hard.  But we have plenty of pumpkins.”

Not all growers were so fortunate.  Many suffered significant losses in the wake of Tropical Storm Irene.  Mark Winslow of Winslow Farms in Pittsford reported that floodwaters destroyed about half his pumpkin crop.  “Approximately 150 tons washed away.  That’s $40,000 in pumpkins.  Because of the loss, we are not able to deliver to our wholesale customers, though we still have an excellent crop for our farm stand.”

Montpelier’s Hunger Mountain Co-op has purchased Halloween pumpkins for over twenty years from a single grower, East Hardwick’s Riverside Farm, said produce manager Robert Kirigan.  This year, about a third of Riverside Farm’s pumpkin crop was lost, so “we are a little short,” Kirigan admitted.

Despite having fewer pumpkins to satisfy demand, prices don’t seem to be any higher than usual this year.  According to Kirigan, “Our pricing is the same as last year.  Although normally shortages would tend to push the price up, we and Riverside Farm decided not to raise our prices.  We wanted to encourage folks to buy real pumpkins, not plastic ones.  And for the sake of the Earth we want them to be organic, not grown with chemicals.  So holding the line on price seemed like the right thing to do.”

With fewer pumpkins around, some vendors turn to out-of-state growers to ensure fully-stocked shelves.  Burlington’s City Market, though, specializes in stocking Vermont pumpkins, produce stocker Kara Brown said.  “We buy them from about five different suppliers, some organic and some conventional.  They’ve all definitely had a tighter supply than last year.”

Dire warnings of a pumpkin shortage hit the media a few weeks after Hurricane Irene inundated the East Coast, with news outlets including the Washington Post, CBS News, and the Wall Street Journal posting stories about the potential for a paucity of pumpkins this fall.  Some pumpkin patches, like those of Winslow Farms, were destroyed outright by flooding.  Even if they weren’t carried away by high water, pumpkins that sat in standing water are illegal to sell—a problem encountered by growers in Burlington’s Intervale.

Irene brought a longer-term, more insidious threat, as well.  Lingering moisture in the fields created an ideal environment for the spread of a host of pumpkin diseases.  Plants may not have to suffer through sore throats or stopped-up sinuses, but they can be afflicted with a wide variety of conditions including wilts, rots, and blights.  Like us, they can succumb to onslaughts by bacteria, viruses, and fungi.

“It may be difficult to imagine,” write Purdue University plant pathologists Richard Latin and Karen Rane in their Identification and Management of Pumpkin Diseases, “but we receive more requests for information on pumpkin diseases and pumpkin disease control than on any other vegetable crop.”

Why pumpkins?  The answer lies in what they are and how they grow.  Pumpkins, of course, are squash.  To a botanist, they’re members of the cucurbit family, related to cucumbers and watermelons.  Most members of this plant family are vines, and pumpkins are no exception; they grow by sprawling across the ground.  Their vines can lengthen by as much as six inches a day during peak growing season.  This rapid growth means that pumpkin plants need rich soil and plenty of water.

The challenge is that too much water creates ideal conditions for pathogens that cause rot and decay. Particularly problematic are puddles that persist on the ground in the pumpkin patch.  You probably know how disappointing it is to find a pumpkin that looks perfect from the top, but that has a big soft spot on the underside, sometimes with visible white mold.  This is Phytophthora blight.  The name is a mouthful, but it’s telling: “phyto” means plant in ancient Greek, and “phthora” means ruin or decay—so you can think of Phytophthora as the Plant Destroyer.  There dozens of different kinds of Phytophthora; one, Phytophthora infestans, caused the Irish Potato Famine.

The species that infects pumpkins is called Phytophthora capsici, and it’s a tricky thing to fight.  It used to be considered a fungus, but it has a few strange traits which have led taxonomists to reclassify it as an oomycete, in a different kingdom of life altogether.  Like fungi, it spreads by producing spores.  One kind, called an oospore, is round and thick-walled; it’s built to last and can persist in the soil for years.  But Phytophthora’s other spore type, known as a zoospore or swimmer, is the fascinating one.  Each swimmer sports two little whiplike tails that it uses to propel itself through water.  The existence of these swimmers means that Phytophthora is more closely related to diatoms and marine plankton than it is to fungi.

There are other diseases that infect pumpkins, too, and many of them thrive when there’s a lot of late-season moisture, as there was this year.  In fact, the susceptibility of pumpkins to disease, combined with strongly-seasonal demand (pumpkins are worth a whole lot less if they go to market on November 1), sets them up as a crop that has potential for shortages.  Luckily, weather that creates ideal conditions for disease is usually localized.  In any given year, there’s probably some region of the country that has a pumpkin production problem … but there are plenty of other pumpkins in the patch, if you’re willing to go a little farther afield.

That’s good news for those of us who are shopping for pumpkins, but small consolation for farmers who suffered losses during Tropical Storm Irene.  “I just wish there was a real insurance program for specialty crops,” said Winslow.  “We do not use the government program because our past experience is that it is completely inadequate.”

Rock: The Best Thing about Vermont

by Becky Cushing

I’m not a geologist, but recently I learned a thing or two about Vermont bedrock that bumps it above maple syrup or cheese on Vermont’s “Best of” List.

By nature, I ask a lot of questions: What trees are those? How deep is this soil? What bird lives in that nest? Turns out, a lot of the answers are directly or indirectly related to the kind of rock below. And in Vermont, those are calcium-rich rocks—which create an alluring hotspot for many cool, rare or economically important plants.

Picture Vermont 500 million years ago, covered by a vast ocean full of planktonic organisms—a primordial soup. Over time, generations of these tiny organisms died and their bodies drifted to the seafloor laying down sediment full of calcium. When the land shifted and the ocean receded, these compressed sediments formed the basis for the calcareous bedrock of today’s Champlain Valley, mostly dolostone.

So what’s the deal with calcium? Plants need it for metabolism and structure, just like we do. It also helps to raise the pH of the soil (thus lowering the acidity). The chemistry gets a little complicated—but find enlightenment (like I did) in a bottle of Tums. Calcium carbonate, well-known for soothing heartburn, also neutralizes acidity in soil making it more alkaline. Who cares? Bacteria, for starters. And those rascals are necessary for making nitrogen available to plants. In fact, under acidic conditions many nutrients give plants the cold shoulder—instead they’re hooking up with each other or leaching out of plants’ reach. Where dolostone (or limestone) is close to the surface (thanks to several glaciations and years of other erosive processes) these nutrients are more willing.

Farmers have known this forever and call neutral or alkaline soils “sweet.” Plant biologists know it too. I’m embarrassed to admit it took nearly a semester of botany for me to pick up on the pattern of our field trip locations—calcareous bedrock stared me straight in the eye.

Maidenhair Fern

Maidenhair fern near Gleason Brook (photo courtesy of Ryan Morra)

For instance, check out the Long Trail near Gleason Brook in Bolton, VT. If you park in the lot off of Duxbury Rd. and hike up a quarter mile or so, you will start to see telltale plants of calcium-enriched soils like maidenhair fern, wood nettle, blue cohosh, plantain-leaved sedge and white baneberry (doll’s eyes). Sugar maple, white ash, basswood and hophornbeam dominate the tree canopy while striped maples sit eagerly in the understory. Stay on the trail to find the dense patch of pale touch-me- not, an irregular pale yellow flower, at the base of a steep slope on the south side of the trail. Here the downward movement of soil and nutrients from the upper slope along with the exposed calcareous bedrock create a double whammy of plant nutrient bliss. Scientists describe this type of vegetative community as a Rich Northern Hardwood Forest—sounds fancy but Vermonters are spoiled with this natural community-type in ample abundance.

Wood Nettle

Wood nettle near Gleason Brook (photo courtesy of Ryan Morra)

Vermont’s best-kept secret, dolostone, has broader implications than satisfying curious botanizers. Conservation planners, for instance, can use geologic surveys to identify potential priority areas for rare plants among Vermont’s varying bedrock landscape. If you travel a few miles farther on the Long Trail up toward the summit of Camel’s Hump your heartburn might return—the rock transitions to more resistant igneous and metamorphic rocks resembling the bedrock geology of our neighbors to the east in “The Granite State.” At the summit’s rare (seemingly masochistic) alpine plants thrive under harsh, acidic conditions—yet another botanical treat thanks to the state’s multifarious geologic past. Motley geology begets vegetative diversity.

So, next time you douse your pancakes with maple syrupy goodness, take a moment to thank the nutrient-rich soil conditions integral to the Sugar maple-dominated forest community of Vermont.

And remember the best—and oldest—thing about Vermont is the rock.

 

 

Winding Through the Path of Least Resistance

by Ryan Morra

“Slow down, you’re moving too fast, you’ve got to make the moment last.” Simon and Garfunkel phrased it well. If you look at aerial photographs of the Winooski or Lamoille Rivers in northern Vermont, you’ll notice how dramatically the rivers snake through Champlain Valley with one horseshoe-shaped bend after the next.

The Winooski River

The Winooski River flowing through Burlington and Colchester, VT

The Lamoille River

The Lamoille River flowing through Farifax, VT

Launch your canoe into these rivers and you will come face to face with the phenomenon known in the scientific community as fluvial geomorphology. This phrase has become increasingly familiar to the public in the aftermath of Tropical Storm Irene, where fluvial geomorphologists have been called upon to explain the widespread flooding experienced across the state. But what exactly does fluvial geomorphology mean? It refers to the ability of flowing water (fluvial) to shape (-morpho-) the earth (geo-). To be precise, it is the study of all that (-logy).

Half Moon Cove

Half Moon Cove in Colchester, VT

An easily observable way that rivers shape the earth around it is the formation of the horseshoe-shaped meanders, called oxbows, seen in the Champlain Valley. More curious are the crescent-shaped lakes alongside the river, the most dramatic example of which is Half Moon Cove in Colchester. If your instincts tell you that this U-shaped lake may have once been a part of the Winooski River, you are correct. How it formed river can be explained by first thinking about the path of least resistance for a river.

Paddling down the final stretch of the Winooski in a canoe is a dramatically different experience than trying to navigate the steeper rivers found in the mountains. In the Green Mountains, the steep slope causes the water to flow fast and cut out a straight channel on its way down to Lake Champlain, and there is little need to propel yourself along (adrenaline junkies will still find cause to do so, however). Once the Winooski reaches the Champlain Valley, it begins to follow a far more convoluted path, and it is hard to go anywhere in your canoe without paddling.

The soils in the valley are soft clays, silts, and sands that provide little resistance to the now slow-moving river, so the river will bend around at even the slightest obstacle. Once a meander has developed, a feedback process begins that causes further erosion and meandering. Along the outer edge of a curve, the water moves faster than the water on the inside of the curve, since the water must travel a greater distance in the same amount of time. The water erodes the banks along the fast-moving outer edge of the curve, and deposits the silt and sand along the slow-moving inner bends.

If you want to land your canoe during your trip, you will have greater success along these inner bends, where gradually rising sandbars have been built up through this deposition process. Trying to exit on the outside curve of a river bend will prove far more precarious, as the streambank drops of sharply into the river! As the river cuts away at its own banks, it can eventually cut through the remaining bit of land at between the two river bends, and the channel straightens.

Meander Process

How a meander becomes an oxbow lake (source: http://www.geocaching.com/seek/cache_details.aspx?guid=a2541785-59cc-492b-aefb-06ce29e973c6)

Major floods like those experienced after Tropical Storm Irene are sometimes the catalyst for this final step. While we may continue to alter the flow of a river through creating new dams and reinforcing the banks below streamside roads, river waters will constantly look for their path of least resistance, and we may find that our interests are in conflict with the hydrologic forces facing us.  Next time you enjoy a float down the sinewy channels of the Winooski or Lamoille river, note where each bend and twist occurs. When you take your children and grandchildren out in the future, it may not be the same—fluvial geomorphology may have worked its magic.

Hare-y Transformations

by Claire Polfus

It’s about that time. The leaves hug the forest floor rather than whisper to the wind in the canopy. The nights scatter a frosty pattern across my windows. The cool breeze tantalizes my toes with the anticipation of snowflakes and skis. And, it is dark. It is dark as I wait for the bus in the morning and as I make my way home in the evening. The days are getting shorter and the long nights of winter are starting.

Many of fall’s keystone changes are set off by the diminishing light. One of these is the changing fur of the snowshoe hare (Lepus americanus). Snowshoe hares look like large rabbits (although they are not all that closely related to the cottontails in our Champlain Valley backyards) with extra-large back feet, which they use to run on top of the snow in the winter and evade their predators. Their range extends from arctic tree-line through the extent of the North American boreal forest down to its southern reaches in the high elevations of Southern Appalachia and the Colorado Rockies. Everywhere you find snowshoe hares, you find snowy white winters. In order to camouflage themselves during the snowiest months, they molt from a dusky brown in the summer to a pure white in the winter.

Photograph by Doug Lindstrand/ Alaska Stock http://kids.nationalgeographic.com

In fall, the shrinking daylight prompts the hares to shed their outer layer of brown fur and regrow a new and more insulative white outer fur. The opposite occurs in the spring. While they are molting they are generally at higher risk for predation since they are both brown and white and can blend into neither snow nor ground. One of the most embarrassing sights you can see as you explore the woods in the fall is a white and brown hare frozen in place wishing and failing to be camouflaged against a backdrop of fallen leaves!

Thus far in the evolution of snowshoe hares, the advantages of camouflage in the winter have outweighed the heightened risk of predation in the spring and fall. Unfortunately for the hares, they evolved in a world where daylight and temperature aligned, at least on average, in a certain way. Since climate change is altering temperatures and precipitation but not day length, this alignment is becoming skewed. In Montana some researchers are finding that the period where the hare’s fur does not match its surroundings is lengthening. This is great for predators for the time being, but if hare populations become too deflated, the boom may become a bust for lynx, bobcat and great-horned owls.

Adaptation to changing seasons is necessary for every northern species. As I step out of my house in progressively warmer jackets, I know that the hares up in the mountains are becoming progressively whiter. Soon there will be snow and we will be racing each other across the mountain meadows – if I can find one first!

 

A Closer Look at Cones: Norway Spruce

by Doug Morin

 

Thwack……thwack……

What was that, I wonder?  Never mind, I have to focus.

thwackclunkbang………

Bang? Was that a bang?

thwackbang……thwackthwack

I couldn’t help myself.  I opened the window and look down to the garage and driveway.  Nothing moved.  The neighbors weren’t even home.  Back to work.

thwackthwackthwack

I raced over to the window, catching a flash of rust-colored fur bolting along a spruce branch to the inner tree.  I looked down; the driveway was covered with spruce cones.  I stayed put, waiting to catch the culprit red-handed.  A minute later, the squirrel ran boldly out one of the long spruce limbs, 40 feet above the ground.  It ran to the end of the branch, hung down off it’s back feet, grabbed a cone with its front feet, chewed the cone’s base for a few second, then let it fall.  thwackclunkbang……… The cone tumbled to the ground, hitting the neighbor’s roof, the side of our house, then my housemate’s car.

Norway spruce. Note the swooping branches and drooping branchlets. Source: http://bioweb.uwlax.edu/bio203/s2009/madisen_neil/

Over the course of the last week, the squirrel dropped about 200 cones into our yard and driveway, by my estimate.  The cones were coming off a Norway spruce (Picea abies) tree in our backyard.

Native to Europe, Norway spruce is one of the main trees in the forests of Germany, Switzerland, Austria, and Russia.  In the U.S., it is commonly grown as an ornamental and in plantations, but rarely establishes on its own.   It is widespread throughout the cities and suburbs of the Northeast, so keep an eye out and you will start seeing it everywhere.

Norway spruce may be the tree most easily identified from a distance.  Once you get the search-image, you will be able to recognize it while driving 60 miles an hour on the highway.  An evergreen, Norway spruce has short, dark needles.   The trees usually grow 50-80 feet tall and two feet in diameter, and often have branches almost all the way to the ground.  And, most importantly –here’s your 60mph field mark— branches off the main stem arc upward (“swooping”) while branchlets growing from the main branches are long and hang down (“drooping”).  Swoop and droop – it’s that easy.

Now, back to the cones.  When you imagine a cone, I bet you think of a dry, brown one, light as a feather.  But, cones are not always so. The dry brown ones most of us imagine have passed maturity and already released their seeds.  In contrast, the cones pelting our house were still developing – leathery, green (or pink early in the season!), and dense.  Plenty dense to dent a car, as we discovered.

But these cones are only one of the two kinds of cones conifers produce.  The big cones we tend to think of (and the kind now all over my driveway) are female cones.  They are usually between 1 inch and 6 inches long depending on the species and produce seeds under their scales.  Squirrels eat the seeds, explaining why our squirrel was amassing a collection of female cones.  Lesser known are male cones.

Separate structures from female cones, male cones tend to be small (1/2 inch or less in length) and not as long lasting (they often disappear in days or weeks).  They produce pollen for a short time in the spring then, having fertilized female seeds, their job is done, and

they die back.  Interestingly, the difference between male and female cones explains why the squirrel was dropping cones from high enough to bombard our roof.

Male cones on left, Female cones on right. Sources: http://projectbudburst.blogspot.com/2010/05/look-at-conifer-phenology.html, Wikimedia Commons

Most trees concentrate male cones on their lower branches and female cones on their higher branches.  This serves an evolutionary role: it prevents self-fertilization. With male cones down low and female cones up high, pollen from male cones must get blown by the wind to get high enough to reach a female cone. This wind will usually carry the pollen to another tree.  If, however, the cones were intermixed or the males were on top, the pollen would fall directly into its own female cones.

So, if the tree wants to mate with another tree, rather than itself, it puts its female cones up high… giving them plenty of time to accelerate as they fall before pelting roofs, cars, and the occasional unsuspecting bystander.

 

 

 

 

The Sensual Slug

by Danielle Owczarski

During the first cold days of fall in Burlington, I had a chance encounter with a handsome slug on my way to catch the bus. As I hurried past, it glided effortlessly across the moistened slate walkway, its black leopard-print pattern catching my eye. The image of the mysterious figure drifted through my thoughts during the short bus ride to campus.

Limax maximus, also known as the great gray slug and leopard slug. (Photo:© R.J. McDonnell, University of California, Riverside)

Originally, when I thought about writing a blog on the natural history of the great gray slug (Limax maximus), I imagined the story to be a simple, thoughtful, interesting piece; little I knew of the great gray’s sensual secrets. Those of you with weak stomachs or other sensitivities related to natural reproduction may want to surf your way to a blog about cooking or kittens. This story is for those with unquenchable curiosity and a sensible grasp on nature’s sexual exploits.

The great gray is a hermaphrodite. Within its slimy skin layer are organs that support both female and male reproduction. Lucky for the great gray, it is not a simultaneous hermaphrodite like the banana slug, who can self-fertilize. No, the great gray must entice a partner to share in the event of reproductive triumph.

L. maximus, native to Europe, and naturalized in the United States and Australia by way of food transport, leaves a thick string of mucus on the ground in early summer to attract its mate. This activity happens mainly during the night hours for this nocturnal species, who feeds on mushrooms and withered plants.

When its partner detects the secretions, it will follow closely, taking a soft nibble on the tempter’s behind. In a grand chase (at a slug’s speed), the two head for an overhanging feature (a brick wall, tree, or mossy rock). They begin to writhe in what seems a blissful engagement, rubbing and twisting around each other’s lubricated bodies.

As the foreplay advances, they begin to fall gently from their perch, attached only by a dense strand of slime, their pendulous bodies entwined in mid-air. Next, in unison, from an opening (gonopore) on the side of each slug’s head, the penises emerge and begin to entangle. The elaborate spiraling of the white translucent penes forms the shape of a flower similar to that of a blossoming morning glory. The unified form then takes on an azure glow and fertilization ensues. The sperm travels up through the twisted organs, through the gonopores, and inside the slug’s body finally reaching the eggs. The act is complete, both fulfilling their reproductive desires.

It would be biased to leave you with an unspoiled depiction of the great gray’s reproductive story. On some occasions when the entanglement becomes too complex and the slugs are unable to pull apart, apophallation must occur. They chew off one or both penises to relieve the imbroglio and the great gray is left with one working organ to continue its life’s work.

For those of you who can’t get enough, check out David Attenborough’s video clip of the great grays in the act: Limax maximus Reproduction Video.

Blue jays and bird colors

by Nancy Olmstead

The woman who lives downstairs from me feeds the pigeons almost every morning.  I know she’s out there when I hear a great swooshing of wings: dozens of pigeons flutter down to our driveway to greet her.  She’ll also put out peanuts for the squirrels.  Sometimes a crafty blue jay slips in there and grabs a peanut.

One of those wily blue jays flew up to the fire escape outside my kitchen window, and as it was adjusting its peanut, I got a good look at it.  Blue jays are such a bright blue color; it’s shocking in our Burlington landscape of brown and gray city birds.

Birds come by their colors in different ways.  The blue of a blue jay is not a pigment; it’s created by the physical structure of the feather.  The color is all in the way the molecules are arrayed.  If you ground up a blue feather, thus breaking apart the structure, there wouldn’t be any color anymore.  If you backlight a blue jay feather, you won’t see the blue anymore.  Next time you find one, place it between your eye and a flashlight beam, or hold it up to the strong sun – no blue.

In contrast, northern cardinals borrow their bright red color from plants.  The carotenoid pigments that make a cardinal red can’t be synthesized by animals; they have to be ingested from plants in a bird’s diet.

What are all those feather colors for, anyway?  Scientists know that birds have good color vision.  In species where the male and female are colored differently, color is usually important in mate choice.  A female American goldfinch is picky about which male she partners up with – a male with lovely, bright yellow color is preferred, while a male with drab plumage could find his partner straying.

Colors can also be structurally important.  The most abundant feather pigment is melanin, which gives strength to areas of the feathers that need to be particularly resistant to wear, like wing tips.  Herring gulls are a good example of a bird with these melanin-rich wing tips – they show up as an almost-black color.  Many terns also have this pattern of dense melanin pigmentation at the wing tips.

I’m not sure what role color plays in the life of a blue jay, but I’d like to find out.  Male and female blue jays look pretty similar to me, so perhaps color isn’t a big deal in mate choice.  Or maybe there are small, subtle color variations that I haven’t picked up on yet.

I should team up with the lady downstairs.  I could bring the blue color chart and maybe she could bring the bag of peanuts.

Fern Surgery

by Carly Brown

The hand saw sits on the disinfected countertop. Fresh fern-appropriate soil waits in a bucket next to my workstation.  I wheel the ferns in on their ‘gurney’, a garden cart that I pull through the greenhouse to the office. I pass by the succulents, the lipstick tree, and finally the cacti. I am wheeling the ferns in for surgery.

As a greenhouse student employee I work in House 2 amongst the pitcher plants, orchids, and ferns. Once a week I scout the area for greenhouse pests. My hand lens is more or less permanently pressed to my right eye as I search for spider mites, thrips, and aphids (more on that in another post).  Today, however, is fern bisection and transplant day. I have transplanted before, but I have never cut plant clusters into pieces to put a smaller individual back into the original pot. The ferns have not only outgrown their pots, but will soon outgrow their area in the greenhouse if they are not cut back.

Removing the large leather fern from its pot is not a task for the weak. Its deep green, shiny, waxy-looking fronds rise up above my head as it sits on the counter. The pot is dense with secret underground growth. Using all of my strength, I flip the pot upside down and rap it against the edge of the counter until the fern slides out of the pot. Catching it in my hands, I flip the fern right side up. Intricate roots and underground rhizomes support its structure enough that it retains the pot shape. The rhizome on a fern is comparable to the stem on a flowering plant. Though it is below the soil it gives the plant a sturdy structure, much like our legs.

I grab my surgical tool: the saw. The goal is to divide this fern into four equal sections. I start the cut, putting all of my muscle into it, but the saw does not make progress. I move the saw back and fourth, but it does not go deeper into the soil. Is this possible? Am I trying to saw through a piece of metal that I did not see? My muscles strain as I push and pull – back, forth, down – until I finally feel the saw going deeper into the soil. After the saw makes it halfway, something gives. I have made it through the hard, almost woody, rhizomes of the fern, and can now detangle the more delicate roots.

Pulling apart the fern base, I am mesmerized by the beauty in the mess of rhizome structures weaving in and out of each other. I have admired ferns in the forests and fields, and have recently tried delicious fiddleheads smothered in butter.  Despite my above-ground admiration, I have never known what goes on in the life of a fern below the cover of soil.  After making a second bisection I place one section of the fern in its old pot and fill it with new soil. This new soil hides the fern’s secret – its solid, intricate, rhizomatous base. After returning the leather fern to House 2, I drench the dry soil with water to jumpstart the growth that will eventually reveal the secret to another naïve student employee on transplant day.