I Scream, You Scream, We All Scream for Isoprene

Plants are well known for absorbing carbon dioxide from the atmosphere and replacing it with oxygen as part of the photosynthesis process. But that’s not the only thing they put into the air. Trees emit tons of a chemical known as isoprene every year, mostly during summer months. It’s surprising to learn that plants contribute to air pollution. 

An abundance of isoprene can lead to formation of greater amounts of ozone by combining with nitrogen in the form of NO and NO2. Ozone in higher levels of the atmosphere is good because it blocks harmful UV rays from the sun, but at our level it’s a major pollutant.  

The current theory is that plants produce isoprene as a method of heat resistance. Like water vapor and oxygen, it is emitted through the pores in a plant’s leaf. Not every plant produces isoprene, but the biggest producers in the US are oaks and poplars.  

Shenandoah National Park (NPS)

Isoprene is what gives the Blue Ridge Mountains their blue appearance. The chemical haze scatters blue light, which makes the mountains appear blue from a distance. It also gives the Smoky Mountains their smoky appearance. 

Great Smoky Mountains (NPS)

We learn such shocking things about nature. I had no idea before today that plants are polluting the air with volatile organic compounds, which when man-made seem to be about the worst thing under the sun. Yet here they are, also giving some of our national parks their distinguishing features and even namesakes. 

Information comes from National Center for Biotechnology Information and Department of Energy Office of Science.

The 17 Year Itch

That sound you hear isn’t the Six Million Dollar Man using his bionic powers. It’s cicadas by the billions. Every year, at least a few cicadas emerge during late spring and serenade us with their mating call. Chunky and scary looking, these insects are totally harmless but to me at least, just hearing them makes it feel a little hotter and muggier. 

This year is a little louder than most. Brood X, the largest brood of periodical cicadas, is emerging after 17 years underground in the larval stage. They’ve been tapping into tree roots during that time and now that they’ve reached adulthood they’re ready to go out in a blaze of noisy glory. They'll mate soon, lay their eggs in the tree tops, and die. When the eggs hatch, the larval cicadas will drop from the tree, burrow into the ground, and start the timer on another 17 years.

Expect it to be a little louder than usual in the Northeast
(From "This Is Spinal Tap")

All those bugs means not just a lot of noise, but also a lot of food for just about everything. The reason cicadas emerge by the billions is to overwhelm their predators’ stomachs. The strategy is that lots of cicadas will get eaten, but based on sheer numbers, many will survive to continue the life cycle for another 17 years. 

Periodical cicada (NPS)

Speaking of 17 years, why such an odd number? It’s another evolutionary strategy. What other critter can you think of with a 17 year life cycle? It reduces the risk of broods emerging during a population boom for a predator species. As a double failsafe, broods have stragglers that emerge either before or after the 17 year period.  Most are within a 13 to 21 year period. It gives the brood a better chance of survival in the event that the 17th year is a boom year for predators. 

Molting cicada (Baltimore Sun)

I've never seen a cicada coming out of its shell. Like all insects, they have a hard exoskelton, and immediately after emerging they molt. From what I'm being told, people all over are finding a lot of those shells on tree trunks and other surfaces. I haven't seen any yet this year, but I haven't been able to get outside much other than a birding expedition to New Jersey which you can read about later. This week's information comes from the University of Connecticut. 

Species of the Month

Introduction: World Elephant Day is next week, so to celebrate we’re profiling one of the world’s three

elephant species. In addition to the Asian elephant, did you know there are two different African

elephants? There’s the forest elephant and the more commonly known bush elephant, the August

Species of the Month.

African bush elephant (Wikipedia)

 

Scientific name: Loxodonta africana

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Proboscidea (elephants)

Range: Central and southern Africa

Habitat: Savannah, forest, deserts

Lifespan: 60-70 years

Diet: Grasses, herbs, fruit, tree leaves, and tree twigs, roots, and bark

Predators: Lions, African wild dogs, hyenas, crocodiles, humans

Mother and calf (Wikimedia Commons)

Conservation Status: Elephants are listed as vulnerable on the IUCN red list. They are threatened under

the US Endangered Species Act.

Other Information: The African bush elephant is the largest land mammal in the world. An adult male

can weigh over six tons with a shoulder height of ten feet. Adult males live alone or in small groups,

while females and calves will form a larger herd led by a matriarch. Calves are raised communally

and are totally dependent on maternal care for several months. They reach full independence around

eight years old. Elephants don’t grow their tusks until after they’re a year old and the baby teeth fall

out. They also have a conveyor belt of six molars that wear out and fall out, allowing the next in line

to move forward. After losing the last molars, they can no longer eat properly. The large ears are great

for hearing, but also dissipate heat. Elephants are very mobile with a large range because of the

massive amount of food they need to eat. They can drink up to 50 gallons of water a day. Mud and

dust baths help them keep cool. Predators mainly go after small calves that fall behind the rest of the

herd. The greatest challenges facing elephants are caused by humans. Development has caused habitat

loss, and keep in mind these giants need a lot of room to roam. Poaching is also a serious threat. Most

elephants are confined to protected areas, limiting their population sizes. However, even at a protected

reserve elephants aren’t safe from poachers.

Young elephants at the watering hole (Sierra Club)

This week’s information comes from Animal Diversity Web.

Glossary of Terms

Here at Nature minute, we use a lot of big words, or even just smaller words you've probably never heard before. It's a fine line between going over your head with technical terms and dumbing it down too much. In the interest of walking that line, here are some of the words you might hear thrown around the office or in the field.

Alluvium- eroded sediments, deposited on land by water. Areas are sometimes referred to as "alluvial plains"; these are where the soil is made up of mostly alluvium.
Benthic- the bottom of a body of water. A river bed and the sea floor are benthic zones, or benthos. Benthic also refers to the organisms living in the benthos.

These insect larvae are benthic creatures

Brumation- a state of lowered metabolic activity in cold-blooded animals; it is similar to hibernation.
Crepuscular- active around dawn and dusk. Deer are crepuscular mammals.

Deer being crepuscular in my back yard, circa 2015

Epiphyte- plants which grow on other plants, but are not parasitic. In the Pacific Northwest, ferns often grown in trees.

Epiphytic ferns

Ephemeral- seasonal. During the spring melt, ephemeral streams and waterfalls form in the mountains.

Ephemeral waterfall cascading down a hillside

Fossorial- digging species which live mainly underground. Moles and badgers are fossorial mammals.
Hadal- the deepest oceanic zone. Deep sea trenches are the hadal zone.
Littoral- the nearshore zone of a body of water, from the high tide line to the shoreline.

This horseshoe crab is in the littoral zone

Torpor- a state of lowered metabolic activity and body temperature in warm-blooded animals. Like brumation, it is similar to hibernation.
Transpiration- water exhalation by a plant. Water is lost as vapor through pores in the leaves.
Ungulate- mammals with a hoof. They come in 2 orders: Artiodactyla, which have an even number of toes, and Perissodactyla, which have an odd number of toes. Those crepuscular deer are ungulates.

Species of the Month

This month we are looking at one of the largest mammals in North America, the moose. Since they are
found in the northern areas, I decided the dead of winter is a great time to profile this great beast. If you
are ever lucky enough to see one, they are best viewed from a distance. Size may be deceiving. They
move quickly and won't hesitate to mess you up!

Moose in Alaska (NPS)

Scientific name: Alces alces

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Artiodactyla (even-toed mammals)

Range: Northern North America

Habitat: Forested areas near freshwater

Lifespan: 8-12 years on average

Moose shedding his antler velvet (NPS)

Diet: Twigs, bark, and roots of trees- especially aspen, willow, and conifers; aquatic plants during
summer months

Predators: Wolves, bears (black and grizzly), humans

Conservation Status: Species of Special Concern in Michigan; no special protection in other areas

Other Information: The moose is so cool! Or at least it strives to be. Body size, coupled with an
inability to sweat, means they have to seek shade and water in or to avoid overheating during summer
months. Just how big is a moose? They can grow to be 7 feet tall at the shoulder! Males grow antlers
for mating season and shed them afterwards. Those antlers, largest in the animal world, can span 6 feet.
Calf mortality is high- 50%. Due to their size, calves are more likely than adults to suffer predation by
wolves or bears. Adults are armed with sharp hooves, in addition to those huge antlers on males. Moose
disease is a fatal brainworm parasitic infection, also seen in deer. Ticks also present a problem. They
can weaken a moose to the point of death from blood loss.

Mama moose with calf in Michigan (NPS)

Our moose information comes from University of Michigan's Animal Diversity Web.

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

Sound of the Wild

Think about the sounds you typically hear over the course of a  normal day. It starts with the alarm clock and quickly fills with noise. The toaster, the hairdryer, the microwave, cars, cars, and more cars, people talking and shouting, buses, trucks, trains, planes, and of course your phone. If you're lucky you heard some birds singing on the way out the door. Other than the lawnmower, popcorn, and a log on the fire, my favorite sounds come from a land far from modern conveniences.
Next time you are out and about pay attention to what you hear. Insects buzzing, birds singing and calling, the wind in the trees (or your ears). In the mountains you might hear pikas and marmots barking, or larger animals like coyotes or wolves howling in the distance. In the fall, you might be treated to the eerie sound of bugling elk.

A not-so-distant coyote, not howling

Water is life, and it also provides a great soundtrack. I can listen to crashing ocean waves or a gurgling river all day long. Rain falling on surfaces other than pavement is a wonderful experience. The pattering on a tree canopy is soothing enough to forget about being soaked, and rain falling in a pond is a magical sound. In a naturally quiet environment like a cave, there's a good chance you'll hear only a single drop of water at a time, maybe a few seconds apart, maybe a few minutes. Even better than rain is the sound of thunder in the distance. This can be a bit worrisome if you're a long way from shelter.

The soothing sounds of the Firehole River

Late summer nights, if there is no thunder, fall asleep to the sound of the crickets. In the spring, fall asleep to the sound of the tree frogs. Another special spring sound, which I've only heard once, is the knocking sound the trees make after the thaw when they start absorbing water and their sap is flowing again. It took a while to figure that one out.

Pacific tree frogs, a sure sign of spring

Here is a link to a short video of some sounds recorded at Yellowstone National Park. Note that the pictures don't necessarily correspond to the sounds. See how many sounds you can figure out!

A Dove Affair

A little over a month ago, I was having a normal morning until I thought a mourning dove was about to crash into the dining room window. He pulled up and landed in the flower basket. Then I noticed he had pine needles in his mouth and passed them to his mate. They were building a nest. I was about to become a bird uncle!

Mother dove feeding one of the babies

I don't know for sure when the eggs hatched, but about three weeks later I got my first look at one of the babies. By then the flowers in the basket were dead and brown, perfect camouflage for the doves. A second baby was in there too, I just didn't notice it for another week. By that time, the babies were almost adult sized. They were up on the edge of the basket flapping their wings, getting ready to fledge the nest.

Baby dove

The last time I saw one of them it was on the edge of the basket flapping during a severe thunderstorm. Through the glass, I was trying to convince it to not try flying in such nasty weather. The next morning, it was gone. A few hours later I watched as the second baby flapped at the edge of the basket, then took off and flew into the neighbor's tree.

The children are getting older

It took less than a month to build a nest, lay eggs, hatch them, and fledge the nest. I was sure my little friends would be around at least until summer. Every now and then I'll look out the back window and see a pair of doves in the yard, or perched on the fence. To me they all look the same, but I can't help thinking it's the same ones I watched grow up.

Have the prodigal doves returned?

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".

Habitat Rehab

Habitat restoration is one of the most important challenges facing conservationists today. Without adequate habitat, endangered species can’t be recovered. Many human activities require restoration as well. Fully functioning wetland systems can provide flood control and clean drinking water. How does the process of habitat restoration work?

Restored coastal marsh, where dikes were removed to
allow the sea to once again access the land

The first step, as in medicine, is “First, do no harm.” A site evaluation will determine exactly what needs to be done to restore what once was. Noting current conditions establishes a baseline for measuring success of the project. It might involve stabilizing a feature immediately, such as an eroding stream bank. After figuring out what needs to be done, the next step is figuring out how to do it.

In many cases, conservationists will use a reference site similar to what is being restored to determine plants and other features. Plants will influence what kind of animals will begin using the site, but the land and water on the site will determine what plants can live there.

Live willow stake planted to reforest
a former pastureland

A lot of times, restoration work is more than simply replacing plants and animals that lived on a site before people came in and messed it up. A site I monitored in Washington had once been a thriving salmon stream with a wide flood plain. 19^th century farmers drained the area by straitening the stream to allow water to flow in and out faster. They also cleared the trees. Fast forward to the 21^st century, and we’ve figured out that the stream needs to be slowed and shaded. Over a period of several years, the curves were put back in the stream and thousands of new trees and shrubs were planted. Fixing the stream required building temporary dams, removing fish by hand, and using heavy equipment to excavate a new stream bed at just the right depth and slope.

Ohop Creek after being restored to its twisted ways

After work has been completed, the site must be monitored for success. There should be some kind of measurable goal, and even if the restoration fails it can be a lesson for future attempts. The site I mentioned was restored for salmon habitat, and while it will take a few years for trees to begin cooling the water temperature, it has been under constant observation since work began. Several times a year, conservation groups involved in the restoration work check water levels, tree survival, how many salmon are spawning, and what kinds of animals are using the habitat. All of this is checked against initial observations from before the project began.

This prairie, currently a restoration work in progress,
was a field of weeds a few years ago

My work with habitat restoration has been monitoring (documenting wildlife and animal signs, as well as plant survival rates), site maintenance, and invasive species removal. The work is hard and sometimes conditions are brutal, but I find it to be very rewarding.

In many cases, restored habitat is second rate compared to what it once was and what nature has provided. It’s not for a lack of trying, but nature is a much better architect of natural features than what man could ever hope to be. But it’s better than nothing.

Ancient Trees

When you think of ancient trees, you probably think of petrified wood. You may be shocked to know that there are some ancient trees that are still living. The oldest known living organism is a bristlecone pine in Nevada that is over 5000 years old. When this tree sprouted, writing was a new concept and Egypt was under the rule of its first pharaohs. In fact, the pyramids weren’t even built yet, although Stonehenge was an active construction site.

Bristlecone pine (US Forest Service)

Other ancient trees are the giant sequoias of California in the 3000 year old range and limber pines date back to the 3^rd to 5^th centuries. East of the Mississippi, the oldest tree is a northern whitecedar in Ontario, which was just a gangly teen of 1100 years old when Columbus sailed the ocean blue. Other trees around the world are estimated to be over 3000 years old, with a yew in a Welsh churchyard that might come close to 5000 years old.

Limber pine

None of those ancients come close to the ages of some cloned trees. Clones are genetically identical to the parent tree. Rather than germinating from a seed, they grow from the parent tree’s root system. Genetically identical Huon pines in Australia are estimated to be 3000 years old. Norway spruces in Sweden, which normally live to be about 600, are growing from live roots that are estimated at 9000 years old.

The king of ancient trees is the Pando in Utah. The Pando is a grove of quaking aspens with about 47,000 trees growing from a single root system. The individual trunk parts of the aspens average 130 years old, but the entire system is estimated to be anywhere from 80,000 to a million years old. The heaviest known organism in the world, the Pando recently made headlines because it is dying. Like so much else in the world, the cause of death is human activity.

The Pando (Smithsonian)

This week's information comes from Wikipedia, of all places. Not to be trusted as a reliable source, it's a great place to find lists.