Species of the Month

Christmas is upon us once again and in keeping with tradition, we have another festive Species of the
Month. American mistletoe, like its European cousin, is a Christmas symbol dating back to the arrival
of European settlers who brought their customs with them. The mistletoe association with Christmas
dates back hundreds of years before Europeans reached American shores. Learn more about this little
plant below!

American mistletoe

Scientific name: Phoradendron leucarpum

Kingdom: Plantae (plants)

Class: Magnoliopsida (dicots)

Order: Santalales (hemi-parasitic plants)

Range: Eastern and Southwestern US

Habitat: Forest, swamps, and desert

Diet: Sunlight and water for photosynthesis; xylem and phloem of host plant through parasitism

Predators: Birds and small mammals

Conservation Status: No special protection

Mistletoe berries

Other Information: While it may bring good luck to have mistletoe in your home during Christmas, it
certainly isn't lucky to eat the berries. They are poisonous to humans, though not usually fatal. Mistletoe
is hemi-parasitic, meaning it is a parasitic plant but can also photosynthesize. Berries contain a single
seed, which is spread by when birds defecate after eating the berry. The seed is sticky, and with any
luck the bird will be sitting in a tree when it passes. This sequence of events gave mistletoe its name.
"Mistle" the Anglo-Saxon word for dung, and "tan", the word for twig were combined, as folks in
those days noticed mistletoe grew were birds left dung on the branches. Because it seems to grow out
of nothing, mistletoe was thought to have fertility properties. Mistletoe acts as a parasite by growing
a root-like haustorium (your big word of the day) through the host tree's bark and tapping into its sugars
and water. Parasitization can cause the host tree to become deformed or distorted.

Pine tree with deformations from mistletoe

This week's pictures and information come from University of Wisconsin at LaCrosse.

Changing Leaves

Fall is in full swing. The sun keeps the air warm, but it's chilly in the shade. Honking geese fly overhead and crickets chirp throughout the lengthening nights. Dried leaves swirls about in the breeze, while those still in the trees for a riot of color. What is going on inside the tree that causes the color change?
Trees are getting ready for a long winter's nap. Like animals going into hibernation, everything is slowing down. Trees have been gorging themselves on sunlight all summer, and now their metabolism is slowing down. The chlorophyll is breaking down and water uptake is stopping. Chlorophyll absorbs all wavelengths of light except green, which is reflected back to us. Without chlorophyll, we see other chemicals in the leaf.

A yellow sugar maple catches the late morning sun

The yellow leaf of a sugar maple

Xanthophyll colors the leaves of aspens, birches, and beeches a bright yellow. It's also found in corn.  Red and purple in red maples and scarlet oaks comes from anthocyanin, which is produced when the chlorophyll stops and the leaf metabolizes extra sugars. Carotene, the same as what you find in a carrot, gives trees like sugar maple and sassafras their orange leaves. Orange can also come from a leaf that is showing both xanthophyll and anthocyanin. Brown, such as in oaks, comes from tannins. Carotene and Xanthophyll are present all year in the leaves, but are overshadowed by chlorophyll.

Another sugar maple, this one decked out in red

This red sugar maple leaf fell of a Canadian flag

The brilliance of each color, as well as the amount of colors relative to each other, are dependent on the weather. If fall is sunny and dry, trees will produce more anthocyanin. Trees will be a more brilliant red. Other years, trees won't produce as much or even none at all and nearly all leaves will change to yellow.
But of course, each tree is an individual so it may change well before its neighbor or have different or more vibrant colors, even among the same species. I've seen red maples that look like traffic lights with red, yellow, and green leaves on the same tree. I've even seen multi-colored leaves.

Brown oak leaf, rich in tannin

Yet another sugar maple, this time in orange

Get out there and enjoy some biochemistry in action before it's too late! The leaves have been great this year, peaking in my area this week and next. Up north you may be past peak, and down south it's on its way! This week's information comes from SUNY College of Environmental Science and Forestry and Montana Natural History Center.

Yellow and brown hickories and oaks basking in late
afternoon sunshine

Reef Madness

Last week we explored the dynamic barrier islands, a great place for wildlife and a popular vacation destination. This week, we venture beyond the island into the coral reefs just offshore. As an avowed landlubber, I'll probably never get to see a coral reef for myself, but I'll live vicariously through myself telling you all about them.

Coral reef (Smithsonian)

Coral reefs are hard, rocky structures made of the skeletal remains of what was once living coral. Corals are a marine animal, not a plant, and the best-known form a symbiotic relationship with algae. Because algae needs sunlight for photosynthesis, many coral reefs are found in clear, shallow water. Cold water corals that live in the deep sea. Without sunlight, these organisms filter feed plankton. Because of their inaccessibility, we are still learning about them.

Coral polyps (NPS)

The most popular corals are the shallow ones, because they are relatively easy to reach. Scuba diving, snorkeling, and even glass bottomed boats bring humans right to the biological hot spots. People are drawn to coral, not just because of the beauty of the coral itself, but the amazing biodiversity found within the reef. Fishes, crustaceans, sponges, anemones, and countless other sea creatures call the reef home. The coral structure provides hiding places for mobile critters and anchorages for sessile ones. Hiding places benefit predator and prey alike- they provide somewhere to hide from bigger fish, or place to launch a quick strike at an unsuspecting meal.

Coral reef (NPS)

Cold water corals provide the same habitat and ecosystem, and may be even more important than their shallower counterparts. Most sea life can be found near the coast and relatively shallow. Corals in the deep sea for a sort of island in an area that is otherwise mostly devoid of life.

Deep sea cold water coral (Joint Nature Conservation Committee)

Like just about every ecosystem in the world, coral reefs are in trouble. Coral is dying as sea temperatures and carbonic acid levels rise. The algae component of the coral either dies or evacuates in a process known as coral bleaching. Some corals show some resistance to slightly warmer temperatures. Research into this is continuing. If you ever get a chance to explore coral reefs, either by boat or underwater, remember to look but don't touch.
This week's information comes from NOAA and the Smithsonian Institute.

Cave Life

This week is Cave Week, so to celebrate we're going spelunking to see what critters we can find. In addition to all sorts of whimsical formations, caves host a surprising amount of life. There are trogolobites, which live full time in caves; trogolophiles, which live in a cave but can also survive outside; and trogoloxenes, the part time cave denizens. You can encounter insects, fish, birds, mammals, plants, fungi, and others. Because there is very little natural light, many of these species are adapted to live in darkness; some don't even have eyes.

Whimsical cave formations

The first cave critter that comes to mind is a bat. Many bats roost in caves because they are cool and dark during the day, making it easier to sleep. Caves make a great place to hibernate over the winter. A constant temperature that is above freezing is an obvious plus, but it's cool enough to trigger the hibernation process. Other cave mammals include bears and jumping mice.

To the bat cave! (National Science Foundation)

Plants are a rare find in  caves because they need sunlight for photosynthesis. I saw ferns growing in a cave under a ceiling hole that opened to the surface. Much more common are fungi, which thrive in dark, damp conditions. Most important among them is Pseudogymnoascus destructans, which causes White Nose Syndrome in bats. It is devastating bat colonies across the US and Canada, and enjoys the cool temperatures while the bats hibernate.

White Nose Syndrome affecting these bats (NPS)

Cave fish are interesting little critters. Nearly all lack eyes and skin pigment. With no light to see by, there is no need to camouflage or stand out, so they are likely to be white or light colored. Unable to see their food, they find it by sensing movement in the water. What exactly do they eat? Since plants, the base of the food chain can't really live in a cave, anything in there either needs to go outside for good or eat whatever gets brought in. Cave fish eat detritus that washes in during rain events. Other critters get by on dung, the leaving of larger animals that way out.

Blind cave fish (NPS, Rick Olsen)

Cave Week runs through this weekend. Find a cave near you and check it out. Spelunk safely. Use the buddy system, carry at least three light sources, and make sure someone knows where you are going. Don't disturb any wildlife and make sure clothing and equipment are thoroughly cleaned before entering another cave. This helps prevent the spread of White Nose Syndrome.
This week's information comes from the National Park Service and National Geographic.

Species of the Month

To celebrate Easter, let's take a look at one of the non-native wildflowers popping up in front yards everywhere. The Species of the Month, grape hyacinth, is not a true hyacinth like those Easter flowers with a strong scent. Until a few years ago, I never knew the name of this little flower, but always called it grape flower because it looks like a bunch of grapes on end.

Scientific name: Muscari armeniacum

Kingdom: Plantae (plants)

Order: Asparagales 

Range: Native to eastern Mediterranean to Caucasus but now distributed in other areas

Habitat: Forest, meadows, yards and fields

Diet: sunlight and water

Conservation Status: No special protection

Other information: This little flower is a popular decorative plant. It can be found blooming in your yard from March or April to May or June, for about two weeks. Plants are dormant summer through winter before reemerging with the spring. This plant bears fruits, small green ones that turn brown by May. A small plant, grape hyacinth reaches about ten inches tall at most. It likes full sun, well-drained soil, and to be surrounded by friends- it does best when planted in bunches.
This week's information comes from The Ohio State University.

More Winter Adaptations

The dead of winter is nigh upon us. It had been relatively mild where I am, despite a colder fall than usual. Unlike this time last year, we are having some temperatures above freezing. I deal with the cold by putting on this flannel,

but how are some more of out animal friends coping?
The wood frog survives by going into suspended animation while buried in mud or leaf litter. For all intents and purposes, it is dead. It survives the cold (and insect-free) winter because it produces a natural antifreeze that keep the water in its cells from freezing and bursting.

Wood frog (MN Dept. of Natural Resources)

Deciduous trees also have to work around internal ice causing cells to burst. In late summer they prepare for winter by shedding their leaves, which reduces the surface area that snow and ice can accumulate on. That protects branches from breaking. They also drastically reduce water consumption. It won't be needed without photosynthesis happening, and less water stores in the trunk is less risk of water freezing and causing a rupture.

Leafless trees that gave up drinking

Snapping turtles survive by spending the winter underwater. Lucky for them, water freezes from the top down rather than from the bottom up. The cold water and lack of oxygen may seem less than ideal living conditions but somehow the turtles survive by changing their blood chemistry to compensate for increasing levels of acid.

Snapping Turtle (Missouri Dept. of Conservation)

Insects also are able to adapt to winter conditions. I always assumed they flew south ahead of the birds or just did when I was younger. Some use the same antifreeze method as the wood frog. Others allow themselves to freeze without becoming ice, a process known as supercooling. Supercooled fluids remain liquid at temperatures below freezing. But the risk is always there that a single particle could allow ice crystals to form. Once that happens it's game over.  The fluid instantly iced over, killing the insect.

Supercooled stonefly (Scientific American)

While you are enjoying the snow from inside your cozy house, just be thankful you don't have to rely on chemistry or dehydration to make it through the winter. And next time you need a snack, it probably won't be your last for a few months.
This week's information comes from the Minnesota Department of Natural Resources and Bernd Heinrich's book "Winter World".

Deciduous Decisions

In the plant world there are two types of trees: deciduous and evergreen. Deciduous trees give us spectacular displays of fall color before shedding their leaves. Evergreens provide a shadow of summer with a splash of green during the bleak winter days. Both types of trees use the leaves (broad leaf or needle leaf) for photosynthesis, but obviously the deciduous tree evolved to opt out of photosynthesis during winter while the evergreens evolved to work a longer season. Which tree has the competitive advantage until the spring greenup?

Life in the wild is all about two things: making babies and being energy efficient. Depending on the environment and situation, being deciduous or evergreen offers a competitive advantage by saving energy, but of course it also comes at a price.

Deciduous trees typically live in areas with temperature fluctuations. Here in the northeast, we have a nice mix of deciduous trees: maples, oaks, hickories, poplars, and more. We also have four distinct seasons. Winters can be snowy, and for a tree that spreads it branches quite a distance from its trunk, not having leaves to catch a heavy snowfall could be the difference between losing limbs or not. Evergreens compensate for snowfall by having a conical shape and shorter branches, with the longest at the bottom. The branch structure allows snow to fall to the next level of branches relatively quickly.

Summer deciduous

While the loss of leaves saves branches, it costs the tree energy. A tree must have enough energy stored up for next spring’s new leaves by fall. Because photosynthesis uses energy (much like chewing and digesting your food burns calories), deciduous trees evolved to shed leaves when there is less sunlight, not enough to be worth the energy expense to generate some more energy. While the deciduous trees are standing idly through the winter, evergreens take advantage of their ever green leaves (either needles or broad leaves in the tropics) and photosynthesize for a longer season or year-round in the tropics. They gain a little more energy that way, and we’ll see why next.

Late fall deciduous

Those expendable deciduous leaves are fairly flimsy compared to a pine needle or palm frond, which are built to last. Less energy is required to build a full set of maple leaves than pine needles. More of the maple leaf is dedicated to photosynthesis than a pine needle, which needs more compounds for structure and defense. Unit for unit, a maple leaf generates more energy than a pine needle. Evergreens, conifers especially, use that conical structure to capture more sunlight to maximize energy production.

Summer evergreen conifers

Deciduous trees thrive in nutrient-rich soil. If there are plenty of nutrients to absorb, they can afford to shed leaves. They often draw remaining nutrients from the leaves back into the trunk before shedding leaves. They even contribute to the nutrient cycle with their fallen decaying leaves. Evergreens have adapted to nutrient-poor soil. They keep their leaves because of a lack of available nutrients. If you look at how green and full of life the tropical rainforests and dense forests of the Pacific Northwest are, you may be shocked at how poor the soil actually is. The nutrients are usually absorbed right out of the dead material into the upper layer of soil and into the living trees.

Winter evergreen conifers

The different leaf styles also lead to different strategies for water conservation. When stressed due to dry conditions, deciduous trees will shed their leaves early to stop water loss. During photosynthesis, water is drawn from the roots to the leaves to make it happen, and the trees exhale water vapor. Evergreens keep their leaves, but they have a waxy cuticle on them that helps prevent water loss.

Hopefully you have a better understanding of why trees do what they do. With fall here and winter on the way I think we can appreciate both leaf styles for the splashes of color they give us. How is the leaf situation in your neighborhood?
This week's information comes from an article by Frances C Smith in the journal Maine Naturalist. 
Frances C Smith: Smith, F. (1993). Evergreen vs. Deciduous Woody Plants: Which Wins Where. Maine Naturalist, 1(4), 205-212. doi:10.2307/3858181 

Species of the Month

This month’s species of the month is a useful tree that provides sweets in the spring, shade in the summer, aesthetic enjoyment in the fall, and many manufactured products. The sugar maple is an important part of the natural world as well as an ornamental plant in cities and towns. Within the next few weeks they’ll be changing from verdant green to an explosion of color.

Sugar maple in its summer finest (The Spruce)

Scientific name: Acer saccharum

Kingdom: Plantae (plants)

Class: Magnoliopsida (dicots)

Order: Sapindales (flowering plants)

Range: Eastern US and Canada

Habitat: Moderately wet forest, occasionally drier slopes

Lifespan: 500 years

Diet: Water and sunlight

Predators: Deer, moose, snowshoe hares, squirrels, porcupines, humans

Conservation Status: No special protection

Sugar maple leaves (USDA)

Other Information: Sugar maple is the only tree suitable for the production of maple syrup. Nine or ten gallons of tree sap boiled down yields about a gallon of maple syrup. Deer, moose, and snowshoe hares browse the maple, while porcupines eat the bark. Squirrels, including the flying variety, eat seeds and buds. Many different songbirds build nests in the branches, while woodpeckers will nest in cavities. Bees will visit the flowers for pollen, even though pollen is spread by the wind. Aside from syrup, humans use sugar maple for wood. Furniture, flooring, and bowling pins are among the many maple products on the market. Leaves change color in fall before dropping. Colors vary by region but can be red, orange, or yellow. Some trees will have any combination of those colors rather than turning to just one. Leaf peeping in New England is a major tourism draw. You may recognize the sugar maple from the Canadian flag. Sugar maple seeds are in the fruit, which you probably played with as a kid. It's the little helicopters or you can make a mustache out of it. Information this week is from USDA. 

Sugar maple fruit (USDA)

Fall colors on display (Bartlett Tree Experts)

Species of the Month

This month’s species of the month is the state flower of California, the California poppy. This flower is not found exclusively in California. It brightens roadsides all along the west coast. Its sunny orange color makes me think of summer sun, a fitting match for the first day of summer.

Scientific name: Eschscholzia californica

Kingdom: Plantae (plants)

Class:   Magnoliopsida (dicotelydons)

Order: Ranunculales (flowering basal eudicots)

Range: Baja California north to Washington, east from southern California to El Paso

Habitat: open areas with well-drained soil, grasslands, oak savannahs, deserts

Lifespan: may be annual or perennial, depending on local climate

Diet: sunlight and water

Predators: hoverflies, beetles

Conservation Status: no special protection

Other Information: A familiar sight along roadways in the far west. California poppies close their flowers at night and on cloudy days. These sunny flowers love sun! Flowers have four petals of bright orange to light yellow. It enjoys disturbed areas. Poppies growing in a mild winter climate are perennials and will grow back for several years. In cold winter climates, they are annuals and grow from seed every year.

This week's information comes from USDA, another USDA site, and US Forest Service. Pictures are from USDA.

I'm Lichen This Blog

This week Nature Minute will take a look at another unsung hero of ecology, the oft-overlooked lichen. There are many different lichens and they can be found just about everywhere. You’ve probably seen lichens. Maybe a greenish-gray circular spot on a rock, or on the bark of a tree (mistakenly referred to as moss).

Last year, I did a two-part series on the importance of soil. Lichen is just as important to life, if not more so, because lichen will frequently colonize bare rock and secrete chemicals that break down the rock. Thus begins the making a toehold for more advanced plant life to follow. This succession is the beginning of soil formation.

Notice above I said “many different lichens” and not “many species of lichens”. That was intentional, because while a lichen is a living organism, it is not a single species, but a symbiotic odd couple relationship between a fungus and an alga (singular of algae). Some lichens will have a green alga, some will have a blue-green alga, and still others will have both.

How does this crazy living arrangement work? The fungus provides the lichen’s structure. The algae provides the food through photosynthesis. In many cases, the fungus and the alga are perfectly capable of living on their own. Yet for some reason, sometimes they chose to live as roommates in a lichen apartment. There must be an evolutionary advantage.

Perhaps it is the chemicals produced by lichens. Very few insects munch on them, although tundra animals will. They are also very hardy, able to withstand complete desiccation. I don’t know of any fungi or algae that can do that on their own.

Because of the separate living components of lichen, it is impossible to trace the evolution of lichens like we can trace other organisms through DNA and the fossil record. So scientists can’t say how this unlikely partnership formed, although they can tell us how new lichens are made. Because it’s different species living together, you can’t just have a male lichen mate with a female lichen. The fungus and alga can reproduce individually, but their offspring won’t necessarily form a new lichen. However, the lichen can form a soredia, a group of the alga’s wrapped up in filaments provided by the fungus. This little ball of oddities rolls off and starts a new lichen. Another way for lichens to “reproduce” is for a piece of lichen to flake off and drift to a new home.

I hope you enjoyed this week’s fascinating look at one of nature’s weirdest partnerships. Now that you know how weird those mundane little blotches are, maybe you’ll take a closer look. Enjoy some lichen photos I’ve taken during my sojourns. Lichen information this week comes from the USForest Service and the University of California’s Museum of Paleontology here and here.

Lichen on a rock in Idaho

Lichen on a rock at Yellowstone NP

Several small patches of lichen on a rock

Lung lobaria lichen on a tree in Washington

Lichen in the branches of a tree in Washington

Lipstick cladonia on a tree stump

False pixie cup on a tree stump

The Trees Must Be Crazy

Fall has finally fallen here in the Northeast, at least for a few days. In parts of the Northwest, it may already seem like a distant memory as an early winter is settling over the Cascades. Seasonally, despite the wacky weather, it is a perfect segue into this week’s Nature Minute: the odd foliage of the Pacific Northwest.

Everyone knows the old line about deciduous trees ending chlorophyll production in the fall. We see the leaves change colors and drop off annually. Also, you know that evergreen trees keep their green needles year-round. They actually shed needles constantly, but stay with me here! What if I told you that in the forests of Washington, some of the trees have it all mixed up?

In areas less than 50 miles or so from the Pacific coast, there is a deciduous tree called the Pacific madrone or madrona tree. It has thick leathery leaves, and it keeps them all year. Unlike the maples, oaks, cottonwoods, and alders of the Northwest that go bald every year by November, the madron sheds its leaves every other year.

Pacific madrone

Leathery leaves of the Pacific madrone

Unripe berries of the Pacific madrone. The berries will ripen in fall and winter,
providing a much-needed food source for birds and other critters.

Another tree that defies the consensus is the larch, a conifer found on the east slope of the Cascades. Like its friends the firs, spruces, and pines, the larch has needles on its branches. However, once fall arrives, the larch’s needles turn golden yellow and fall off. That’s right, the Northwest has an evergreen deciduous tree and a deciduous conifer. Now that everything you know is wrong, the big question is why. The easy answer is that no one knows. But fall is a great time to curl up with a mystery.

Summer larch (British Columbia Ministry of Forestry photo)

Fall larch (Herb Museum photo)

Solar-powered Cycles

You probably noticed by now that the days are getting shorter and the air is a little chillier. Fall has fallen! The sun gives life to everything on Earth through heat and energy for plant photosynthesis. It also triggers changes in life cycles, some of which are evident to almost everyone right now.

The most obvious cycle that is affected by the sun is the current situation with our tree leaves changing colors and falling off. Because Earth’s axis is tilted 23 degrees, we experience seasonal variances in the amount of sunlight we get. As we move through fall and into winter, the sun sinks lower in the sky and light that hits us is less direct.

Nature loves efficiency, and trees lose their leaves this time of year because with decreasing sunlight, they would expend more energy performing photosynthesis (turning sunlight, water, and carbon dioxide into energy) than they would get from it. Chlorophyll, the active photosynthesizing pigment, dries up and the cells in the leaf stem die, weakening it to the point that it falls off the tree. Until spring arrives, trees and other plants live off of starches stored in their roots. That starch is the byproduct of photosynthesis.

Other seasonal cycles are the leafing out of trees, hibernation, and mating seasons. Some cycles run by the sun can be daily, not just seasonal. Dandelions and other flowers close their petals at night. Daily sleep cycles are also affected by sunlight. Animals don’t use an alarm clock, but they do have an internal clock.

Bigleaf maple

Even shrubs change colors