Hard Working Animals

Police dogs, draft horses, barn cats, and lab rats are all animals that could be considered to work a full time job. In a salute to Labor Day, here are a few wild animals that work just as hard as humans and domestic animals.

Earthworms are working hard to keep your garden healthy. Often overlooked because they remain unseen, these slimy little guys are tunneling all day, allowing air and water to move around the soil. They cycle nutrients by eating decaying plant matter, creating fertilizer that living plants can use. 

Earthworm (Christian Science Monitor)

Mound building termites built mud homes that can reach heights of 17 feet and displace a quarter ton of soil. It can take years to build, and a single heavy rainstorm can damage or destroy it. Worker termites are always on the ready to make repairs as needed. Additionally, they also farm a fungus as a digestive aid. The fungus breaks down partially digested cellulose from the wood and grass the termites had eaten. After the fungus does its thing, the termites re-ingest what the fungus broke down.

Termite mound (Journal of Experimental Biology)

Beavers are the best known engineers in the animal world. They build water tight dams out of sticks and mud. Ponds form behind the dam, and while the beavers selfishly build dams and create ponds for themselves, the important wetland habitat benefits many other species as well. Even humans benefit, as the wetlands filter water and serve as flood control.

Beaver preening

Beaver dam

While you're enjoying a long weekend, just remember the critters that work hard 365 days a year just to survive. This week's information comes from National Geographic for worms and termites.

Crater Lake

This month is six years since my visit to fabulous Crater Lake National Park in Oregon. America's deepest lake at nearly 2000 feet in depth, it sits inside the collapsed caldera of an ancient volcano. Wizard Island near the west side of the lake is a volcano within a volcano. The lake is fed entirely by rain and snow. The amount falling in each year is nearly equal to what evaporates of leaks out the bottom. Crater Lake is what I can only describe as being impossibly blue. Pictures don't do it justice.

Crater Lake seen from West Rim Drive

In addition to the lake, the park also features forests, wildflower meadows, waterfalls, pumice deserts, cinder cones, and formations called pinnacles. The pumice deserts were formed by volcanic eruptions depositing pumice. Like sand, it drains very well so there is little moisture retained in the ground. Like in a true desert, only the hardiest plants can scratch out a living. 

Pumice desert

The pinnacles were originally volcanic steam vents. As gas and steam were released, moisture mixed with the surrounding ash and formed a thick cement. Mount Mazama, the ancient volcano that formed Crater Lake, had its last major eruption 7700 years ago. Following a massive eruption of ash and pumice, a huge explosion caused the mountain to collapse into itself. 

Wizard Island, a caldera within a caldera

Red Cinder Cone, a shadow of the volcanic past

While visiting Crater Lake, I got to do a bit of exploring. I started a sunset hike up The Watchman, one of the peaks along the crater's rim. I got turned around by an incoming thunderstorm. On another hike across the pumice prairie and through a burned forest, I turned around when I lost sight of the horizon with more storms in the forecast. I went down into a canyon along a mountain stream and back up, saw the pinnacles, a waterfall, and small meadow with varying degrees of wetness. Different wildflowers were growing in different areas due to elevation, soil, and moisture levels- a great example of zonation.

Some of the wildlife in the park includes Clark's nutcracker, golden mantled ground squirrels, mule deer, black bears, foxes, bobcats, and pika. I was lucky enough to see the ground squirrel, deer, gray jays, and a tiny frog.

After leaving Crater Lake, I headed to the coast and stayed at the Oregon Dunes. There was no activity at the Sea Lion Caves nearby. The next stop before going home was a quick visit to Mount Hood. I stank after a week in the woods without showers, but the adventure was worth it. This week's information comes from USGS and NPS. All photos are my own. I'll be taking a break for vacation and will return in September with a look at some hard workers, just in time for Labor Day.

Wind Energy

Wind energy is another “clean” energy using the power of moving air to generate electricity. It is renewable because there is no shortage of air on the planet, and it is constantly in motion to a varying degree. It is not completely reliable because the wind is not always blowing, although the wind turbines are at least 100 feet above the ground to take advantage of the less turbulent and more abundant airflow, as compared to ground level.

Wind farm (US Department of Energy)

Wind energy currently makes up 4% of the US energy mix, but is growing and will eventually pass
hydroelectric as most rivers are dammed to capacity. An ideal place for wind farms in the central US
“Tornado Alley” because of nearly constant strong wind. Wind farms are compatible with the
traditional farms of the region and are an economic boon for farmers. They can lease land to energy
companies for windmill placement, and still have the ability to use nearly all of their land. Ridge tops
in the Appalachians are another great location, where topography produces adequate wind speeds.  

Developing technology has greatly improved the efficiency of windmills. Lighter blades, taller towers,
and control systems have increased the average capacity factor from 22% in 1998 to 33% in 2014. As
the race to replace fossil fuels continues, expect efficiency to increase further.

The downside to wind energy, aside from lack of wind, includes environmental impacts. Construction
of windmills in undeveloped areas requires access roads and site preparation, which can be a strain on
the environment. Leaking lubricants can pollute the soil. Birds and can be struck and killed by
windmill blades. However, fewer birds are killed by windmills than stationary buildings. Many birds
are learning to avoid areas containing windmills. Tornado Alley windfarms are away from major
flyways so migratory birds are less likely to affected in that region.

Birds and windmills are not always a good mix (NBC News)

Other negatives are aesthetics and safety. Many people believe the windmills are unsightly and ruin the
landscape. One workaround for that is to install them in developed areas, where they might actually
improve the view, especially if the view is mainly housing developments and shopping centers.
The focus then shifts to noise. The rotating blades can be noisy, depending on the distance from the
listened but the elevation above the ground helps reduce that.

Safety can be an issue when rotating blades are involved. Machines malfunction, and should a windmill
throw a blade, the potential for human death is there. A serious concern in Tornado Alley is that a
namesake tornado could destroy a wind farm and turn the blades into deadly projectiles.

This week's information comes from National Renewable Energy Laboratory, Mount Holyoke College, and US Department of Energy. Next week we'll take a look at solar energy.

Species of the Month

Introduction: This month we celebrate the Easter season with a wild variety of one of the holiday's
decorative flowers, lilies. April's Species of the Month is the Columbia tiger lily, native to the Pacific
Northwest where I first encountered it.

My first Columbia tiger lily sighting

 Scientific name: Lilium columbianum

Kingdom: Plantae (plants)

Class: Liliopsida

Order: Liliales (lilies)

Columbia tiger lily with neighbors in its community

Range: California to British Columbia, northern Idaho and northwestern Montana

Habitat: Open woods or fields with well-drained soils and partial shade

Diet: Sunlight and water

Conservation Status: No special protection

Like the others before, this lily is growing on a mountainside

Other Information: Bright and cheery flowers adorn this lily, which can grow to six feet tall with a
dozen blossoms, although it is typically only three feet tall. The stems droop so the flower faces
downward. Depending on elevation, flowers bloom from June to September. I discovered the tiger lily
in the Cascades, in a forest clearing along the trail. For a good portion of the year, those few plants I
saw are buried under deep snow. Alternate names include Columbia lily, Oregon lily, and tiger lily. I
prefer not to use "tiger lily", as I associate that name with the larger, decorative plant.
This week's information comes from USDA and Lady Bird Johnson Wildflower Center. All photos are
my own.

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.

Crickets

Fall has almost fallen. It's hard to believe summer was in full swing when you last read a fresh Nature Minute blog. Internet issues and life in general kept me from my regular schedule. Maybe where you are, the leaves are starting to turn, there's a bit of crispness in the air, mornings are full of fog, and nights are longer and full of chirping crickets.

Black field cricket Gryllus assimilis (Texas A&M) 

Here in Pennsylvania, crickets typically begin their nightly serenades in the late summer, continuing through the fall. Only the males chirp. They do so by rubbing their wings together, as a mating call for the females. They are most active at night, and even during daytime are hard to find. If they notice you getting close, they'll stop chirping so you really need to look hard if you want to find the source of the chirp. Warmer temperatures will produce more chirps, and the number of chirps drops with the temperature. I never counted chirps before, so I never noticed this.

Northern mole cricket Neocurtilla hexadactyla
(University of Florida)

Many people consider crickets to be a pest because the chirping gets annoying, but they are generally harmless. Since crickets favor loose soil, they are frequently found in flower beds, which are usually right under your bedroom window, giving you a front row seat. At the bottom of the food chain, in large numbers they have the potential to attract other unwanted guests to your home such as raccoons and spiders.

Carolina ground cricket Eunemobius carolinus
(Oklahoma Panhandle State University)

Nature Minute will return in October with more autumnal awesomeness. I'm taking a much-needed vacation. Until then, relax to the sound of the crickets. Don't let them drive you nuts. They'll only be around a few more weeks, and then it will be too cold to keep the windows open at night. This week's cricket facts come from Terro.

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.

Superfund Site

While I was working toward my environmental science one of my classes was Environmental Law and Policy. For one of our assignments we had to research a Superfund site and present to the class. The site I chose was less than a mile as the crow flies from where I grew up. At that time, EPA hadn’t begun work on the site. Last year after moving back to Pennsylvania, I attended an EPA meeting on the status of the cleanup. This year, as work nears completion, I was able to tour the site with EPA’s Tim Gallagher.

Contrary to what you might think, not all Superfund sites are full of leaking drums of glowing green radioactive waste. The Watson-Johnson property was a landfill from the 50s to the 70s, then forgotten about. In the late 90s, water testing revealed several contaminants in the groundwater. One of the town wells for the water supply was closed. The solution the EPA came up with was to cap the landfill and use chemical injection to neutralize the contaminants in the groundwater.

Watson Johnson landfill site. The geosynthetic is
buried under 18 inches of soil here.

Capping the landfill is a common practice at sites like this. Why not remove the waste? Odds are, everything would just be taken out of the ground and buried in another landfill somewhere else. One oozing container was discovered and removed from the site, but otherwise it was all collected together and capped. The cap uses a layer of compacted clay soil, a waterproof synthetic fabric, more soil, and vegetation. The purpose of the cap is to keep the waste contained and keep water out, preventing anything from seeping into the groundwater.  Water drains to wetlands, ponds, and level spreaders. Level spreaders are cement cisterns that capture water and allow it to overflow and slowly spread away from the site.

Drainage swale around the outside of the capped landfill.
Grass seed has already been spread inside it.

Level spreader beyond the edge of the capped landfill

The soil above and around the cap is contoured to divert surface water away from the cap. There are natural wetlands on site, as well as new artificial wetlands created to contain and disperse runoff. The cap itself layered in a way that creates pathways for gases flow towards several vents. Because they site was once open but now is closed with those release points, concentrations are higher. Methane has been noted at the vents, but not volatile organic compounds (VOCs).

Gas vent. No monitors are attached.

Monitoring and injection wells reach the groundwater. Sodium permanganate is injected to react with the chemicals in the water. The reaction breaks down the chemicals (including the sodium permanganate) into harmless elements like oxygen and hydrogen. Monitoring wells are set up to test the levels of chemicals in the water. Injections will stop once the concentration goes below 100 parts per billion. At that point, EPA will begin bioremediation. Microscopic critters that eat the contaminants will be injected to the groundwater to bring the contaminants down even further.

Work on the site is nearing completion. Despite a cold winter and rainy summer, work is only two months behind schedule. Workers are currently adding a layer of topsoil six inches deep on top of the cover soil. Once topsoil is in place, it will be seeded with native grasses. Around the cap, workers are setting up deer fence to protect new trees that will be going in. Landscaping was supposed to start last week but was delayed by heavy rain.

EPA will continue to monitor the site for a year after completion, before turning that duty over to the state. Future plans include nesting boxes for swallows and bats. The new trees will create a nice matrix with the older existing woods on the edge of the site, which should attract songbirds that prefer new growth. The site is privately owned, so it will not become a park like old landfills in other areas. However, development will be limited by cap so it will likely remain a nice green oasis as the area becomes increasingly more urbanized.

For more information visit the EPA's Watson Johnson website. Special thanks to Tim Gallagher for taking time out of his day to show me around.

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 

Everglades Ecosystems

This week and next we’re taking a look at the largest subtropical wilderness in America, the Everglades. What we now know as Everglades National Park is just a fraction of the original Everglades, and unfortunately, almost daily it becomes a larger percentage of what of remains today. While what remains is an incredibly diverse variety of habitats, each with their own plants and animals, it is not without its challenges. We’ll explore what’s so special about this place as well as what’s going wrong there.

In its former glory, the Everglades was a huge watershed. Water flowed south from areas north of Lake Okeechobee and drained to the east, west, and south. Some of the water flowed east and west into the Atlantic Ocean and Gulf of Mexico, respectively, through traditional rivers and streams. Some water flowed out through the slow-moving “River of Grass”, as the Everglades became known as. Where the water goes and how much gets there determines the many different ecosystems.

Many other factors go into building an ecosystem, including geology and climate. To me, what gives an ecosystem its character is its plant life. The Everglades has quite the cast of characters, with grasses inhabiting the freshwater sloughs and marl and coastal prairies. Marl prairie is grassland of thin soil formed on top of limestone bedrock. The soil is high in calcite and the bedrock may be exposed in some areas. Rainwater becomes acidic as it dissolves plant material, and even a weak acid can easily dissolve limestone. The bedrock here is very porous. Marl prairies drain slowly.

Marl prairie (Florida Museum of Natural History)

Freshwater sloughs are main arteries for water flowing to the sea. The water moves very slowly and is very grassy. The sloughs are dotted with “islands” of trees and are bounded by the higher and drier marl prairies.

Freshwater slough (NPS)

Mangrove forests line the channels and rivers in the coastal and estuarine areas of the Everglades. Mangroves buffer the coast from storms, collect sediment to form new land, and harbor a vast array of birds, reptiles, mammals, and fishes. See my earlier blog post for more details.

Mangroves (NPS)

Hardwood hammocks are dense wooded areas on slight rises. Temperate and tropical tree species mingle here, and because the surrounding lowlands are either wet or not land at all, fire rarely reaches here. The dense canopy creates a dark and humid environment where ferns thrive.

Hardwood hammock (NPS)

Pine rocklands form on high ground around exposed limestone bedrock. These forests are less dense than hardwood hammocks. Fire keeps the understory open and hardwoods at bay.

Pine rockland (NPS)

Marine areas of Everglades National Park also have plant communities. Seagrasses stabilize the bottom, trap sediments, provide a nursery for fishes, and feed underwater herbivores. Lobsters, crabs, shrimp, corals, and sponges are also found offshore.

Florida Bay marine habitat (NPS)

Next week we'll look more at the plants and animals of the Everglades, as well as challenges the region faces. Information and photos this week come from the National Park Service.

Desert Life

This time of year, there’s usually no place in America that’s hotter than the desert Southwest. The region is known for its striking red sandstone formations, deep canyons, and ancient ruins. While the desert may seem like a barren wasteland to the casual observer, it is full of life. If you know where to look. The critters of the desert have evolved with special adaptations that allow them to survive in a harsh environment. Let’s have a look at some.

Extreme heat and scarce water are two hardships of the desert. Because of the second problem, sweating is an impractical solution to the first problem. As a workaround, the jackrabbit has large ears which are full of blood vessels. The blood vessels bring warmer blood away from the body core to cool. The large surface area of the ears also helps the cooling process (National Geographic).

Black-tailed jack rabbit (NPS)

The kangaroo rat has adapted to life without beverages. It can go an extended period without water, absorbing what it needs from its plant-based diet. Too keep cool, it lives underground and is nocturnal (Arizona-Sonora Desert Museum).

Stephen's kangaroo rat (Arizona-Sonora Desert Museum)

The various cactus species have evolved to avoid water loss. All plants lose water through their leaves in a process called transpiration. Cactus plants minimize the loss by having long, thin needles in place of the leaves we’re familiar with on trees and other leafy plants. They also have an extensive root system for maximizing water collection potential and a wide, hollow stem for water storage (BBC).

Saguaro cactus (US Forest Service)

Other desert plants have adapted as well. Shrubs and non-woody flowers survive by growing deep roots that can reach down into the water table. They have hardy seeds that can last for years before germinating. When the rare shower falls, these plants simultaneously burst to life in a brief but spectacular desert bloom (Science News for Kids).

Superbloom (National Park Service)

The Great Basin spadefoot toad has a cool adaptation for surviving in the desert. They burrow underground and remain in a state of suspended animation for years until rainfall brings it to the surface for mating and feeding. Mating pairs will lay and fertilize eggs anywhere water collects, then the race is on for the eggs to hatch and tadpoles to develop before the water evaporates. The tadpoles are cannibalistic, which might be an incentive to hurry up and grow (The Nature Conservancy).

Great Basin spadefoot toad (Idaho Fish and Game)

You probably don’t think of shrimp living in the desert. The fairy shrimp’s habitat is ephemeral (seasonal) pools that form in depressions in rock. They are tough little buggers, able to withstand extreme heat. Their eggs can survive desiccation for decades, using sugars instead of water inside the egg. The eggs can remain in place until rain activates it and it hatches, or they can be carried on the wind to a new location and hatch there when rain comes (National Park Service).

Fairy shrimp (National Park Service)

Next time you happen to be in the desert, look around for these and other fascinating critters. The desert is alive, if you look hard enough to see the life all around you.

This is a Crappy Subject

Now for the dirtier side of nature. Pretty much every living thing on this planet exists to be someone else’s meal. If you’re unlucky enough to become lunch, the next step is you become poop. No one likes to talk about it, look at it, or smell it. Even though it’s gross, it’s an essential element of the environment for a couple of reasons.

Raccoon scat

The most important function of poop, or scat as we call it in the science world, is a key role in the nutrient cycle. Every living thing needs an assortment of minerals in order to function properly. Minerals are absorbed from the soil by plants, then absorbed by herbivores that eat those plants, then absorbed by various levels of carnivores up through the food chain. Some minerals are present in the ground in rocks; others are returned to the soil through decaying organic matter (plant or animal) or through scat.

Nutrient cycle (from Exploring Nature.org)

Another important impact scat has on the environment is negative, and it goes beyond getting on your shoe. Nitrates and phosphates are common in scat, and also happen to be active ingredients in fertilizer. Excessive nitrates and phosphates in storm runoff causes high nutrient levels in lakes, streams, and even the ocean. Those high levels can cause an overgrowth of algae. Too much algae, even though it produces oxygen, can cause dead zones of little to no oxygen when the algae dies and decomposers feasting on it suck all the oxygen out of the water.

Algae bloom (Michigan Radio)

A third way scat is important is as a research tool. It allows people like myself who rarely observe animals in the wild to see what animals have been down the trail before. DNA samples can be pulled from scat, and population biologists can estimate population by counting turds. Ecologists can study an animal’s dietary habits from looking at scat.

The coyote that dropped this deuce ate a bird

Deer scat

Now that you’ve seen the usefulness of animal scats, maybe you will look at it in a whole new light on your next foray into the woods. Like anything else in nature (except maybe spiders), if you can overcome your aversion, you can learn to appreciate it.

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