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.

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

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".

Species of the Month

Up on the rooftop click click click, down through the chimney it's the species of the month! Christmas is right around the corner, so it’s time for another festive species of the month. The caribou is the wild version of the domesticated reindeer. Santa’s herd is safe, but their wild counterparts face habitat loss and in some areas have been hunted to extinction.

Woodland caribou

Scientific name: Rangifer tarandus

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Artiodactyla (even-toed ungulates)

Range: Circumpolar- Canada, northwestern US, Greenland, northern Europe

Habitat: Arctic tundra and boreal forest

Lifespan: 4.5 years on average

Diet: Leaves, bark, lichen, mushrooms

Predators: Bears and wolves

Conservation Status: Endangered (US), IUCN Species of Least Concern

Lighter colored tundra caribou (NPS)

Other Information: Caribou are the only deer species featuring antlered females. Not all females grow antlers, however. Male antlers are larger and more intricate. Males use theirs in sparring during the rut. Like other deer species, mating is controlled by a dominant bull who fends of younger challengers. The fights leave males injured and/or exhausted and vulnerable to predators. Domesticated reindeer have been used as beasts of burden and for food for thousands of years. There are several subspecies of caribou. Northern caribou are nearly white and smaller than their southern counterparts. In North America, the woodland caribou is a dark brown and critically endangered. Just a handful lived in the wild in Washington and Idaho. Recently, they were all captured and sent to a secure area in British Columbia to protect them from predators in the hopes that their population will increase. Caribou hooves are very large and concave, serving as snowshoes.

Caribou hoof (Where To Next)

The size and shape also aid in swimming. Caribou migrate long distances and must cross many rivers. When walking, they make a loud clicking sound, caused by a foot tendon rubbing on bone.

Information once again comes from the good people at Michigan’s AnimalDiversity Web.

Domestic reindeer (The Nature Conservancy)

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)

Magnificent Mangroves

It’s common knowledge that trees are important. They provide oxygen, shade, habitat, food, and useful forest products. In tropical and subtropical areas, there is an important tree that is vanishing from coastal areas at an alarming rate- the mangrove.

Mangroves are annoying because they tend to live only at beaches that developers around the world want to develop. Mangroves are wonderful trees because in addition to the ecosystem functions they perform for nature, they also have ecosystem services for humans, if we would just leave them alone. They form a protective barrier against storm surges and trap sediments in their root systems, extending the coast outward as a buffer against sea level rise.

Mangrove forest (USFWS)

Mangrove species are able to tolerate brackish water. They have tall prop roots that keep the bulk of the tree above high tide. The root system slows water, allowing sediments to settle out. Eventually, enough sediment accumulates that the tree is on solid ground and new mangroves colonize the water in front. Small organisms like the safety that mangrove roots provide.

The tall prop roots are obvious at low tide (NOAA)

Mangroves are able to handle brackish water because they have a salt gland, so to speak. They excrete the salt through their leaves, bark, or roots. Some of the leaf excreters keep their leaves, which have a salty coating. Others accumulate salt in the leaf, and shed the leaf when it is saturated with salt. Those that excrete salt through their bark also use the shedding method to get rid of the salt.

Now that we’ve become aware of the mangroves’ benefits, we’re slowly making progress toward preserving the remaining forests. Here in the US, there are three mangrove species (red, black, and white) with a historic range being the Gulf coast and both of Florida’s coasts. Today, the best example of a mangrove forest can be in Florida at Everglades National Park. If you ever get to check out this important ecosystem, please do!

More great prop roots, this time on red mangroves (NPS)

This week's mangrove facts come from NOAA and American Museum of Natural History.

Species of the Month

It’s time once again for the wearin’ o’ the green. To celebrate, our species of the month is white clover. This three-leafed plant is also known as the shamrock, a traditional symbol of Ireland and Saint Patrick’s Day.

White clover leaf (Michigan State University)

Scientific name: Trifolium repens

Kingdom: Plantae (plants)

Class:   Magnoliopsida (dicotyledons)

Order: Fabales (dicot flowering plants)

Range: native to Europe, now globally distributed

Habitat: pastures, yards

Lifespan: perennial plant, at least two years

Diet: sunlight and water

Predators: small mammals such as groundhogs and rabbits, deer, livestock

White clover flower (USDA PLANTS)

Closeup of the flower (USDA PLANTS)

Conservation Status: no special protection, may be considered noxious in some areas

Other Information: Believe it or not, clover is in the legume family with peas and beans. These plants form a symbiotic relationship with fungi that live in nodules on their roots and can absorb nitrogen from the air and fix it to the soil, benefitting other plants. Most white clover plants have three leaves, but the ones with four leaves are considered good luck. The four leaf clover is actually a genetic mutation. There are also clovers with five, six, or more leaves but whether or not they are lucky is undetermined. White clover is commonly planted with pasture grasses for grazing. The Ladino variety is tall enough to be cut as hay. It is an important flower for honeybees. It spreads quickly and is sometimes used for erosion control as a ground cover. Native to Europe, it is an invasive species in the US.

This week's information comes from USDA's PLANTS database.

The elusive four leaf clover (Wikipedia)

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