Ripples 11/ 23/23

Posted on by November 27, 2023

By Jessica Johnsrud, Education Coordinator and Assistant Director

As the busy fall season winds down, I am able to take time to review the bat survey data that Woodland Dunes helped collect for the DNR this summer. Woodland Dunes has a device that can detect and record the echolocation calls of bats and mark the GPS coordinate where each sound was intercepted. This information is uploaded to the computer and transferred to the DNR who then interpret the data. A trained biologist is able to identify the bat species recorded by reading the visual representation of each sound, known as a spectrogram. Just like each bird species has its own set of calls and sounds, so does each bat species.

After the spectrograms are identified, a map is created which includes the survey route and the points where bats were recorded. We have collected data on as many as seven routes in some summers, when the weather cooperates and schedules allow. At a minimum, we do three routes, once of which is on the lower section of the West Twin River.

This survey is always the most enjoyable and relaxing of the season. It’s a “posh” experience because a very generous couple donates their pontoon boat and even drives us. This survey is also the most fruitful, detecting more bat species and individuals than the routes we walk in the preserve or nearby green spaces. This is likely because after sleeping all day, bats fly out of their roosts and are hungry and thirsty. Foraging for insects near the river or other body of water will meet both of these needs. The results of this summer’s survey on the river recorded five bat species: big brown, little brown, silver-haired, hoary and red.

Woodland Dunes has been conducting bat surveys since 2013 and people may wonder why this important. Many bats are insect eaters making them major predators of agricultural pests and biting insects that transmit disease like West Nile. One bat can eat up to 1,000 mosquitos in an hour and about half its body weight each night! It is estimated that bats save United States farmers approximately $22 billion each year in reduced crop damage and limiting the need for pesticide use. These are amazing ecosystem services!  

Unfortunately, bats that hibernate in caves, mines or buildings, have been severely impacted by an invasive fungus that grow on bats’ wings and face during hibernation. The disease is aptly named white-nose syndrome and causes bats to wake up more than usual during the 6-8 month hibernation period, using up precious fat reserves and eventually causing death. The little brown, big brown, Northern long-eared and tricolored (formerly known as Eastern pipistrelle) bats are the cave bats in Wisconsin. I am always extra excited when we received bat survey results and see any of these species.

The data we and other organizations and individuals collect helps provide scientists with more information about bat populations and can help inform management decisions for these amazing mammals. Some bat populations may be starting to slowly bounce back from white-nose syndrome and forms of treatment are being explored, especially for the most vulnerable of the hibernating bat species.  

Bats are wonderful, essential parts of our natural world.  Learning about them, and helping them as a result, will be good for nature, and ultimately ourselves as well.

 

Ripples 11/16/23

Posted on by November 16, 2023
The small and unnoticed play a large role in the functions of nature.  I realize that is a theme we teach over and over, but it is a fact of which we naturalists are constantly reminded.  Majestic large trees and animals are wonderful to see, but they could not exist without the help of their smaller counterparts which keep the whole world running.  At Woodland Dunes, we strive to keep all of nature’s pieces intact, like those in an impossibly large jigsaw puzzle.  Sometimes we lose a piece and it causes us a lot of concern.  In the early days of this place, extensive surveys were done, recording as many plant and animal species as could be identified.  We now compare what we see to what was seen 50 years ago.  Sometimes it’s a bit depressing to do so- species that were once regularly found then haven’t been seen for years.  And once in a while, we find a plant or animal that has been here but hasn’t been detected.
 
One such plant is the American Yew, or Canada Yew (Taxus canadensis).  This small, evergreen shrub was noted in our original surveys and again a couple of decades ago by a botanist looking at clubmosses in our preserve.  However, the exact locations were not recorded and were not remembered, so our staff has not been able to keep track of them.  A few weeks ago, however, two of our staff were working to remove invasive Japanese barberry, and in the middle of a large patch found a single yew.  They caged it in chicken wire, took photographs, and brought back a small branch for verification.  We consulted with other botanists, and confirmed that it was Canada yew.  Then the same crew found two more small plants in the same area.  All had been heavily browsed by deer, and were perhaps saved by the growth of invasive barberry (which eventually would have outcompeted the yew).
 
Canada yew was once widely found in Wisconsin. It is a low shrub a couple of feet tall.  It is a slow growing plant which despite its poisonous nature is heavily browsed by deer.  Yes, the plant is toxic to them, but they eat it anyway.  It contains a substance or substances called taxine which slows heart rate in animals.  A half pound of yew needles are enough to kill a horse.  Maybe deer feel relaxed after eating it- who knows?  And yes, it is toxic to humans, and people do use the needles of some evergreens for making tea, so it is good to be sure of the identity of the plant you are using for your brew.  It also contains another substance called taxol.
 
Yew is low-growing, usually a couple feet tall or less.  It has flat needles resembling those of balsam fir, but the needles are green on both top and bottom, without the whitish lines of balsam on the undersides.  Needles are about an inch long, much longer than those of hemlock.  Both balsam fir and hemlock are upright trees mainly, unlike the low, sprawling nature of yew.  Common juniper is another low evergreen, but has sharp spiky needles rather than soft flat ones.  Its fruit is a red berry-like structure surrounding a single seed.  The red flesh of the berry is the only part of the plant which is not toxic (but the seed is!).  Japanese yew, which is similar in appearance is a cultivated plant from Asia which looks like our native yew and is often planted ornamentally.  It does not seem to be invasive here, but deer like to browse it just like the native species.
 
Canada yew has disappeared from much of Wisconsin as the deer herd has increased.  People love to hunt, and so deer are managed to be plentiful.  The impact on forest plants, however, is significant.  The three little yew that we found have all been caged so they can survive in the face of pressure from deer.  This year we erected two small deer exclosures in the preserve, fenced to a height of seven feet or so.  The intent is to protect planted native shrubs and wildflowers.  Next year we will be putting up a half acre exclosure in the forest, inside which we will plant more vulnerable species like Canada yew.  If funded, we have proposed a nine-acre exclosure in a mature forest area, where many spring wildflowers will be planted.  It will be valuable to study such areas in the future, as we decide how to manage deer in the long term.
 

In the meantime, a missing piece of the jigsaw puzzle of life here has been found, and we are very happy for that.  Finding a lost species, or a new species in our preserve is one of the ultimate rewards for managing a natural area.  It’s the preservation of living history that motivates us, along with sharing the joy of those discoveries and their meaning with others.     

 

Ripples 11/9/23

Posted on by November 9, 2023

By Kennedy Zittel, Naturalist

Taking a walk through a prairie often feels magical, doesn’t it? In the summer months, flowers of a variety of colors, shapes, and textures carpet the prairie landscape. Fuzzy bumble bees buzz flower to flower. Colorful butterflies float on by while dragonflies and damselflies zip overhead. Green sedges and grasses sway in the breeze. Red-tailed hawks soar. All of that color and movement make the prairie feel so alive and magical. 

Now that it is November, some may think that the prairie magic has faded away, lost with the sleeping flowers and disappearance of warm-month pollinators. The prairie, once oh so colorful, is now shades of brown and orange, with a dotting of reddish-purple from sedges and grasses that remain. 

If you’d stop and take a closer look, you’d find that the magic is still there, waiting to be appreciated like it is during those warmer months. 

While standing out in the prairie, milkweed seeds float on by, waiting to see where the wind will take them. Paths of deer zigzag through the grasses. Red fox tracks in the sand show that they are around, with their fur camouflaging perfectly with the colors of old flower stalks. The remaining leaves on surrounding trees, shades of red, purple, and orange fall to the ground every time the breeze picks up, like nature’s confetti. 

Taking a close look at the ground reveals another magical sight. A carpet of soft green moss creeps out from beneath a little blue-stem plant, leading the way to what looks like a tiny dining area… just the right size for fairies! Pale green goblet-shaped cups emerge from the ground. Some are empty, others contain a tiny drop of dew, glittering in the November sunlight. 

Pixie cup lichen (Cladonia sp.), are small fruticose lichen that look like tiny green cups (hence the name). In addition to growing in soil like in the prairie, they can grow on rotting wood, rocks, and bark in both partial shade to full sun. They look like something out of a children’s movie, waiting for a fairy to come and take a drink from one. 

Surrounding the pixie cup lichen are even more lichen species, of all sorts of colors, textures, and shapes. Different types of moss cover the ground as well. Some are shaped like little pillows, perfect for a fairy nap. Others form little blankets that dot the sandy ground with a pop of dark green. 

A loud call brings my attention towards a blue cloudless sky, five sandhill cranes fly overhead, calling to one another. Though I could stare at the magical world of a prairie all day, I do have to get back to work. Picking up a bag of wildflower seeds I begin tossing seeds around the prairie, some falling to the sandy soil, others floating to new areas in the breeze. The hope is that we can help add to the magic, for future people to enjoy as well as for the plants and animals that call the prairie home. 

Photo by Kennedy Zittel

Ripples 11/2/23

Posted on by November 2, 2023

by Kennedy Zittel, Naturalist

To celebrate the week of Halloween, here is a spooky tale of things that glow in the dark… or should I say glow in the light?

Lurking in the depths of muddy pond water, hiding under fallen leaves, these creatures are all over our preserve! And to make it even more spooky… they glow! Any guesses?

Amphibians! No tricks here, they really do glow!

It wasn’t until recently, during studies done in 2020, that scientists realized that amphibians (including salamanders, frogs, and caecilians) have biofluorescence. Biofluorescence is when compounds found within an animal’s body absorb light and then re-emit light back at specific color wavelengths (this means when the animal is under certain light, they glow a different color!). How cool is that?

Note: Biofluorescence is different than bioluminescence. Bioluminescence is generated by a chemical or biological reaction within the animal’s body (think like a glowstick) whereas biofluorescence is when an organism emits light after having a different type of light source shone on it. 

During this study, researchers shone both blue light and ultraviolet light (UV) on different species of amphibians. Then a camera that was able to pick up different green-yellow color wavelengths was used to take their picture. In the study, every species of amphibian that was photographed showcased biofluorescence! 

Not every species glowed the same, the location of the glowing varied, as did the intensity of the glow. Some species, like the Eastern Tiger Salamander, had their bright yellow stripes glow bright green under blue and UV light. Other species had their entire body glow. Some species’ stripes glowed. Some just had their toes glow! Though the location and intensity of the glowing varied, all amphibian species tested glowed a greenish-yellow color. Their glow was also more intense under the blue light compared to UV light. 

Because all species tested (not all species of amphibians have been tested yet) glowed (salamanders, frogs, and caecilians alike), scientists think that the biofluorescence trait appeared early in the evolutionary history of amphibians. But why?

We don’t know yet. Suggested reasons for the glowing could be to help them locate one another in the dim-lighting that amphibians are often found in, communication, camouflage, sexual selection, or even no noticeable function at all. 

Now, amphibians aren’t scary and don’t make for much of a spooky Halloween story. But the fact that there is still so much to learn about these awesome creatures is so neat! Hopefully, the next time you see a frog or salamander you think about how if you were in different lighting… it would glow! Isn’t that a treat?

Image:  scientific reports, “Salamanders and other amphibians are aglow with biofluorescence”

 

Ripples 10/26/23

Posted on by October 26, 2023

Written by Sue Crowley, Land Manager

It is a coldish and rainy day with the wind blowing; the daylight is waning and leaves are floating to ground. For many people these leaves are beautiful and a welcome show before winter freeze and snow set in. However, as evidenced by our language, perhaps these pesky leaves are not our favorite-we have dubbed their collective presence on our yards and on the forest floor with the term, “leaf litter.”  We spend hours trying to relocate leaves away from our yards. And as far as “debris” goes, we ecologists and foresters use the term “coarse woody debris” to describe trees that have fallen to ground and are now slowly decaying. Yet these fallen leaves, seeds, small twigs, branches and even whole trees make up an important layer on the ground just above the mineral soil.

The blanket layer (leaf litter) provides important habitat. It serves as a source of nesting materials for squirrels and birds; it supplies cover for mice and salamanders; and it enables seeds to shelter from hungry birds so the seeds will germinate in the spring.  The blanket layer is home to many organisms like snails, spiders, and millipedes, but also fungi and bacteria.  The cycle is quite brilliant as some will eat and breakdown the leaves into smaller bits. The smaller bits are decomposed further to eventually become mineral soil that contains vital nutrients such as nitrogen and calcium which will support the growth of trees, shrubs and other herbaceous plants.

The haven of a large, downed tree (coarse woody debris) that resides in the woods for many years is much like the blanket of leaves except that it is present for much longer before it is transformed into soil. The long life of a downed tree provides for storage of carbon, hiding places for small mammals, travel corridors under snow cover, substrate for fungi, and even a great place for a tree seed to start its life. Have you ever seen a tree that looks like it is on stilts? Well, that tree most likely began its life on a decaying log and the log has since decomposed into the soil.

I think the terms “litter” and “debris” do not give these vital aspects of our environment the proper credit for all they provide. Perhaps consider leaving a bit of a blanket in part of your yard or just recognizing a large log on the ground when you take a hike because they are a home to many and the source of good soil, nutrients and healthy forests now and in the future. 

Photo credit: rawpixel.com