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October 29, 2005
The Autumn Show
There's no question that fall has arrived at the LREC. The morning air carries a crisp chill, the last of the prairie flowers have died and the trees have begun to change colors.
Have you ever wondered what causes the leaves to turn those brilliant shades of red, orange and yellow, and why it seems that the autumn foliage is more colorful some years than others?
Let's begin with the leaf.
The carotenoids, the pigment responsible for the fall colors, is already present with in the leaf but is concealed by the green color of chlorophyll, the component essential for photosynthesis. The base of each leaf contains a special layer of cells, known as the separation layer, where the exchange of water and food between the leaf and tree takes place.
The leaves are responsible for providing food for the tree and it performs this duty through photosynthesis. In photosynthesis, the leaves use water and carbon dioxide to produce carbohydrates for the tree and oxygen is the by-product of this process. On any given day, the average tree will take in 1-1/2 pounds of carbon dioxide and release about a pound of oxygen into the atmosphere. The leaves also produce more food than is needed and the tree will convert the excess sugar into starch to consume during the winter months.
The shorter hours of daylight and cooler temperatures trigger a reaction that allows the leaves to reveal their autumn colors. During this time, the cells within the separation layer form a cork-like material that cuts the exchange of water and glucose from the leaf. The chlorophyll within the leaf disappears when the water supply is cut off, revealing the hidden oranges, reds or yellows.
The orange leaves are produced from carotene pigments,
yellow leaves are a result of xanthophyll pigments
and anthocyanin create the red and purple leaves.
Interestingly enough, not all trees produce anthocyanin and this pigment is only made during the fall months.
Contrary to popular belief, rainfall is not the only factor responsible for the colors of autumn. Sunlight, cloud cover, temperature and soil acidity also determine the intensity and duration of fall's colorful show. For example, bright light produces anthocyanin. The brighter the sunlight, the more vivid the red and purple leaves. A warm wet spring followed by a summer that is neither too hot nor too dry that leads into a fall with warm sunny days and cool nights will produce a dazzling leaf display.
Now that you know the work the leaves put into their visual displays, I hope you get a chance to go outside and enjoy the last days of Autumn's splendor.
RESOURCES:
Jonas, Gerald. 1993. The Living Earth Book of North American Trees. New York: The Reader's Digest Association, Inc.
King, John. 1997. Reaching For the Sun: How Plants Work. New York: Cambridge University Press.
Stern, Kingsley. 2000. 8th Edition. Introductory Plant Biology. Boston: McGrawHill.
Posted by Colleen Crank at 7:28 PM | Comments (1)
October 18, 2005
Introducing "Creepy" Critters or Respect for All Life
I received the following e-mail from James Trager, Restoration Biologist at Shaw Nature Reserve, and thought it deserved sharing:
With Halloween approaching come teachable moments concerning our "appearance-challenged" fellow life forms. These comments from naturalist colleagues of mine in Iowa...
Greg's comments:As an interpretive naturalist (in Delaware) I did live native animal programs for scout troops, overnight programs, and in classrooms during the winter months. I learned to interview the adults in the room quietly and privately beforehand to see if they were fearful of any of the animals I brought. Invariably someone was afraid of snakes (size and venom were irrelevant). I asked them not to exhibit their fear, or to leave quietly if necessary before the snakes came out. The goal was to avoid a dramatic fear response/scene (believe me it happens) from an adult that would imprint on the kids, especially those in lower grade school. These were largely urban kids, but that's mostly irrelevant. For many it was their first experience with snakes up close and personal and I wanted them to have a positive, informed experience. They were welcomed to touch gently, but no one was forced, and a climate of respect and appreciation was fostered for each animal. We purposely did not give these animals 'pet' names because we wanted the kids to respect them for what they were...namely wild animals deserving of appropriate habitat where they could live undisturbed for the most part. Pet names and cutesy descriptions tend to trivialize the experience. Its a matter of philosophy and personal example, as Chad said. Kids are watching us...Homo sapiens are superb at mimicry.
Everything has it's place. What good are mosquitos? What good is poison ivy? I heard those questions a lot. The trick is to give them another point of reference, the unstated part of these sorts of questions is 'What good is it to ME?'. Lakota tradition regards other life forms as co-equal. Vine Deloria suggests that Sioux ceremonials at the most fundamental level are a manifestation of creation becoming thankfully aware of itself (via human consciousness). Its a perspective largely foreign to the prevailing culture. Maybe that's what ecological restoration is ultimately about...a ceremony, a sacred rite, a celebration...
Greg Houseal
Program Manager, Iowa Ecotype Project
Native Roadside Vegetation Center
University of Northern Iowa
Ginger's response:The example set by adults toward other species has a profound effect on children, and I have seen an entire classroom of kindergarteners mimic the terror their teacher displayed toward a live spider. It changed the way I present information about "creepy" creatures during Naturalist programs. I follow a formula, "My Five Favorite Things About Spiders/Bats/Snakes, etc". My joy and enthusiasm are as contagious as another adult's fear and prejudice.
The final point Greg made is brilliant. Yes, our restoration efforts ARE a ceremony recognizing equal importance among species and celebrating our respect for our fellow living things, plants included. Have you ever met a tree that looked profound? Have you ever offered a prayer of thanks for a hillside of native prairie, so rich in color and motion and life that you wept as you looked at it? Well, maybe I'm a little emotional... Have you ever watched an ancient, sacred bit of earth come alive with beauty and diversity under the attentive, loving care of human hands? If there is a spirit shared equally among living things, we, restorationists, reconstructionists, preservationists, keep it alive in our hearts and in our work.
Ginger Vietor
Aurelia, IA
Posted by Jennifer Krause at 1:12 PM
October 15, 2005
The Hidden Life of the Decomposers
The woods and the prairie at the LREC are teeming with life. On any given walk you may see a squirrel scamper across your path or hear the chatter of a Belted Kingfisher as he hunts for food on the creek. On the prairie you can admire the vibrant Purple Coneflower and watch the bees walk across the goldenrod in search of pollen and nectar.
We tend to focus on the flora and fauna that is immediately and easily visible to our senses. But have you thought about the life that is hidden within a rotting tree, under the leaves or in the ground? There's a whole other world down there, where the decomposers, also known as the detritivores abound. What may seem like a dead tree at first glance is actually a tree teeming with life.
There are decomposers hidden within the crevices of the bark, working hard to break the wood down into material small enough for microscopic bacteria to break that matter further down into good, fertile soil material.
And who are these decomposers? Let's take a look under a tree stump and find out.
The sowbugs are usually the first decomposers you will notice under a rotting tree stump.
These bugs are also known as pill bugs and roley poleys. They enjoy hiding in dark, moist places such as our tree stump. They mostly eat dead plant material and have a sturdy exoskeleton that protects them from harm.
The slug is another decomposer you may find under the rotted tree log. The slugs are members of the gastropod class and they eat leaves, dead plant matter and fungus. The slug moves via its muscular foot and produces two different types of mucus to aid in its movement. The mucus also helps the slug retain much-needed moisture and protects it against potential predators.
There are several critters that enjoy the taste of a slug and these include Beetles, Centipedes,Lizards, Mice, Shrews, Moles, Frogs, Toads, Birds and Fox.
The snails, also in the gastropod class, share several characteristics with the slugs. They move by the same muscular foot, depend on moisture for survival, produce mucus for locomotion and protection and live in the same habitat.
There are a few differences between snails and slugs. Snails have shells that provide protection and a place to retreat during a dry spell. During those times when no water is available, the snail will retreat into its shell and go into a state of estivation, which is similar to hibernation. When rain moistens its immediate environment, the snails come out of their shells and resume their task of eating dead plant material, bark and young plant shoots.
I wanted to include this picture to show you just how tiny these snails were. There is a snail on either side of my finger. Can you find both of them?
These beautiful mahogany-colored wood roaches are quite different from the roaches you may find in your home. These roaches feed exclusively on wood and they contain tiny microorganisms within their digestive tracts that help them break down the wood material they eat. The adult wood roaches feed their offspring, as their young initially lack the beneficial bacteria to help break down their food.
If you find these roaches in your house, it is because they have stumbled in purely by accident. They will do no harm to your house as they much prefer their damp homes within the woods.
Isn't this a shiny, beautiful beetle? These Patent Leather Beetles live within old logs and eat the decaying wood. Their trees of choice are the black and white oaks, American Elm, Yellow Poplar, American Beech and Sweet gum. These beetles live in colonies and within their wood homes they dig tunnels, creating "galleries" where they lay eggs and rear their young. The young beetles stay in the larval stage for about a year and their parents feed them fecal material mixed with wood chips.
There are a lot of other animals in the forest that dine of these beetles. Wood Frogs, Toads, Mice, Snakes, 5-lined Skinks, Moles, Opposums, Wild Turkeys and Woodpeckers.
The centipedes are one of the prime predators of the decomposers. These fast-moving venomous insects eat cockroaches, spiders, termites and a variety of other insects. They have one pair of legs per segement and have claws that aid them in catching their prey.
I found this gem under a rotted tree stump in the woods of LREC. Isn't it beautiful?
Well, that concludes our brief exploration of the hidden life of decomposers. I've only touched on the surface of these fascinating creatures. I didn't even talk about the millipedes, spiders, termites and other recyclers of the environment. Explore them for yourself and have fun learning!
Here are a few of my sources.
Wikipedia
Iowa State University
Pechenik, Jan A., 2000. Biology of the Invertebrates. 4th ed. New York: McGraw Hill
Posted by Colleen Crank at 10:17 PM | Comments (4)
October 10, 2005
Autumn on the Prairie
On September 27, I made a special trip out to the Ecology center with my camera. I wanted to capture the last colors of fall before winter's cold set in. Here are my thoughts and pictures from that day.
Before the Europeans set foot in North America, over half of the state of Missouri was covered in Prairie grasses. The soil was loamy, silty and fertile for the taking. Over time, Missouri's native habitat was transformed into farmland and urban development. Today less than 2% of natural prairie remains but there is a new movement within the Natural Sciences community to rebuild prairie habitat. The Missouri Botanical Garden here in St. Louis is doing a fantastic job of recreating prairie habitat. The MO Botanical Shaw Nature Reserve out in Gray Summit MO has some impressive prairie habitat and the Litszinger Road Ecology Center has a wonderful small piece of prairie land as well.
There is so much life out in the prairie of the Litszinger Road Ecology Center. (LREC) Right now most of the flowers are past their prime and beginning to die off, but some colorful blossoms remain.
Right now the Goldenrod is abundant and a flurry of life surrounds these beautiful prairie flowers.
The prairie is a harsh place and the grasses, flowers and animals that inhabit the land must adapt to a dry, hot climate. Prairie plants have roots that grow deep in the earth, deeper than other plants to be able to reach water. American Goldfinches nest later in the summer, past the time when all the other birds have raised their young. These birds time their nesting activity around the blooming of thistle and coneflowers so that they have a good food source for themselves and their young.
Goldfinches also lose their bright yellow feathers and take on a more drab appearance once Autumn sets in. Here are a few pictures of a female American Goldfinch.
As of September 27 a few hummingbirds were still found lingering around the feeder set at the edge of the prairie. But most of our ruby-throated gems have migrated south now.
This is life on the prairie during Autumn. I look forward to watching the land and its inhabitants change with the seasons. Stay tuned!
Posted by Colleen Crank at 9:46 PM | Comments (2)
October 4, 2005
Spider Web
This spider web was photographed in the pasture prairie about 8:00 Monday morning while the sun was still low and the dew still heavy.
Posted by ejones at 11:22 AM | Comments (2)