Home on the Prairie

Undercover Science

Julianne Beck —  September 15, 2014 — Leave a comment

A delicate prairie bush clover extends its pink flowers toward the sun, like an early settler attempting to plant a flag on a piece of land to call home. Competition for space is intense where the native herb stands on one of the state’s last remaining prairie landscapes, Nachusa Grasslands, located in north-central Illinois.

The species’ juvenile plants must establish themselves rapidly to avoid being overtaken by dominant native grasses, such as little bluestem. Even if the wispy young herbs live to maturity, they may still struggle to survive the often deadly wake of litter the grass leaves behind.

PHOTO: A view of Nachusa Grasslands taken from Dr. Vitt’s field site.

A view of Nachusa Grasslands taken from Dr. Vitt’s field site. Photo by Pati Vitt.

Chicago Botanic Garden conservation scientist Pati Vitt, Ph.D., has been studying the rivalry between the prairie bush clover and grass species at Nachusa over the past 14 years. Also the curator of the Dixon National Tallgrass Prairie Seed Bank, she has seen the herb species’ population rise and fall.

PHOTO: A tiny, spindly stalk of prairie bush clover in spring.

Prairie bush clover ( Lespedeza leptostachya) grows at Nachusa Grasslands.

In Illinois, Nachusa Grasslands is one of the few remaining places where prairie bush clover (Lespedeza leptostachya) can still be found. The issues it faces there are not unusual to the species.

“It is a unique component of this very small subset of North American grasslands that exist nowhere else,” said Dr. Vitt. “Its presence is an indicator of high-quality, well-managed gravel hill prairie. It serves to increase the biodiversity of those types of habitats.”

After years of working to define the ideal environment for the prairie bush clover and getting to know its adversaries, she feels it is time to bring in the big guys.

Bison, 2,000-pound behemoths that are naturally adapted to Midwest weather and vegetation, will soon be arriving to help save the tiny plant. The rust-colored creatures, standing up to 6½ feet tall at the shoulder, are rather particular grazers, explained Vitt. Unlike cows, which graze broadly and without much discretion, bison selectively eat grass. That makes them the perfect friend of the prairie bush clover, which, Vitt has documented, needs a little more room to grow on the limited rocky portion of the 3,000-acre prairie it calls home.

Vitt spent much of her summer at Nachusa, a preserve managed by the Nature Conservancy in Illinois. She was hustling to document the status of prairie bush clover populations there before the arrival of a herd of bison in the fall of 2015.

Little bluestem ( Schizachyrium scoparium ) is a native grass.

Each morning of research she and her team, which included an REU intern, fellow Garden scientist Kay Havens, Ph.D., and additional technicians, were out in the field at daybreak. They worked in teams of two to count and identify all of the plants associated with Lespedeza leptostachya in six plots where it grows. They also took soil samples and did nutrient analysis to measure elements such as nitrogen, phosphorous, and potassium. Lastly, they documented the slope of the land on which the prairie bush clover plants grew, and the aspect—the incline and direction at which they faced the sun. The team spent evenings at their temporary residence inspecting more challenging plants under a microscope to confirm the species identification. All of the data they gathered was recorded into GPS units and later downloaded into a database.

What did they find? Prairie bush clover performs best in soil that has 75 percent versus 82 to 89 percent sand, though all populations grow on soil with low organic matter. It suffers where levels of grass, and especially the litter the grass produces when it dies back each year, are high.

These findings support her research from previous years. Vitt studied the before-and-after status of the species during a one-year trial run with a cow as a grazer. She also investigated the impact of fire as a management tool.

“The more [grass] litter there is, the fewer seeds the [prairie bush clover] plants produce, which is both a function of size and probably nutrient status,” she explained. “Litter may not only serve to suppress the growth of the plant, but because it is carbon heavy it may actually decrease the available nitrogen in the soil.” One of the benefits of prairie bush clover, she theorizes, is that the healthy plants add nitrogen to the soil. That is an asset for surrounding plants.

A research plot where little bluestem is growing over smaller prairie bush clover plants. Photo by Pati Vitt.

A research plot where little bluestem is growing over smaller prairie bush clover plants. Photo by Pati Vitt.

When alternated with fire, grazing is a natural and effective management tool, noted Vitt. Fire, she explained, decreases the biomass of grass above soil, resulting in less grass litter. At the same time, it encourages new growth by stimulating meristems in the roots below the soil—areas where new cells are produced. After fire, said Vitt, clumps of grasses such as little bluestem (Schizachyrium scoparium) tend to be larger. However, when they are also grazed, those clumps are less dense, and therefore less discouraging to growth of the prairie bush clover.

Vitt has collected seeds on other prairies in the Midwest where bison have been present. “I’ve seen firsthand how bison graze, and I’ve seen the results of bison grazing versus cattle grazing,” she said. “When they [the Conservancy] decided that they were going to release the bison, for me that was very exciting. It’s kind of an affirmation of the work that I’ve done there, and that’s really great. I can see the benefits of the management and I have every reason to conclude that it’s going to increase the population viability of Lespedeza leptostachya.”

Bison will soon graze the vast prairie. Photo by Pati Vitt.

Bison will soon graze the vast prairie. Photo by Pati Vitt.

Vitt is back at the Garden now, sorting through the data she collected this summer and writing about her findings. These data are essential, she said, because she will be back to check on the prairie bush clover after the bison have settled in. She is also planning for future experiments, such as building habitat models for prairie bush clover using remote sensed data.

For a little plant that exists in only four states and is federally threatened, a hero can come in many forms.


©2014 Chicago Botanic Garden and my.chicagobotanic.org

Meet Melyssa Guzman. She is one of 20 College First students who spent eight weeks learning about environmental science and doing a research project at the Chicago Botanic Garden. 

2014 PHOTO: College First student Mely G.

College First student Mely G. would like people to plant butterfly gardens in their yards.

Mely, as she likes to be called, is a junior in the Chicago Public Schools district. She’s kind of a “girlie” young woman who wears a lot of pink, and likes flowery, feminine things. Mely also loves science. Each student had a staff mentor; I was Mely’s. Her project was teaching the public about butterfly-attracting flowers.

Although drop-in programs and exhibitions may be considered more “education” than “science,” understanding how people learn is an area of social science research that can challenge a smart student like Mely. This summer, Mely learned that museums and public gardens often test exhibitions and learning activities, using methods similar to those practiced by conservation scientists, to see how visitors will respond.

Mely began by researching butterflies and the flowers they prefer. Then she decided to set up a display at the Butterflies & Blooms exhibition, where she would teach visitors what flowers to grow in their yards to attract butterflies. The display would have different kinds of flowers—real flowers and pictures—and she would stand and talk with people who were interested.

PHOTO: Mely G. taking notes.

After each group of visitors, Mely recorded notes about how long they stayed at her table, and how interested they seemed.

As kids today would say, her first try was an “epic fail.” Most visitors looked at her display with curiosity, but they seemed perplexed and did not stop to learn more. The display was lovely, with fresh flowers and pictures of native butterflies, but it lacked a clear focus. It needed something else to draw visitors in. The display board kept blowing over, which was another big problem.

PHOTO: Mely G. prepares a display.

Back to the drawing board: Mely made a new display— one that would stand up better and entice visitors with a title that asks: “What Is a Butterfly Flower?”

Mely brought the exhibit inside and modified the whole thing. Instead of using a folding display board, she mounted a poster board on a cardboard box so it would be more stable when taped to the table. She added a title, “What Is a Butterfly Flower?” as well as some facts about butterfly flowers. Then she tested the display again. After each group of visitors, she recorded the time they spent at her table, and gave them a score of 1 to 4 to rate how interested they were, the kinds of questions they asked, and things they talked about while looking at the display.

Museum exhibit developers call this process “rapid prototyping.” Inexpensive mock-ups of exhibits are tested to ensure they work—that visitors enjoy them and get the intended messages—before the museum invests a lot of money on a permanent display.

PHOTO: 2014 College First student Mely G. gives a demonstration.

A mother and daughter listen as Mely explains what colors, scents, and shapes attract butterflies to a flower.

Mely made a few more minor changes to her display. Then she tested a hypothesis. She observed that adults with children seemed more distracted than those without children; that they did not seem to talk to her as much as the childless groups. She hypothesized that adults without children would spend more time, ask more questions, and talk more about butterflies than mixed-generation groups. She used the data she gathered during prototyping the display, analyzing who stopped by her table, how long they spent, and how engaged they were.

Surprisingly, she discovered that families with children actually spent a little more time on average than adults alone. She thought this may be true because adults who brought children to her display spent their time explaining things to them instead of talking to her. In other words, the adults were not distracted, but were directing attention on their children to help them also learn from the display.

Mely does not fully realize that she has stumbled upon a very significant principle of learning: that learning is social. Educational research has shown that interaction between family members has a positive influence on learning in museums and in other environments. I’m very proud of Melyssa’s accomplishment this summer, and I look forward to seeing her expand her research next summer—because we both learned something!

©2014 Chicago Botanic Garden and my.chicagobotanic.org

Traveling Down the Glacier

The new North Branch Trail addition opens!

Karen Z. —  September 8, 2014 — 3 Comments

There’s more to the new North Branch Trail addition than meets the eye.

It’s a great story to tell the kids or to share with a biking buddy as you try out the North Branch Trail addition

PHOTO: A view from the boardwalk east to Green Bay Road.

A view from the boardwalk east to Green Bay Road

On the surface (literally), it’s a lovely new bike/pedestrian trail that slopes down from Green Bay Road, skirting the north edge of Turnbull Woods and linking up to the outer road of the Chicago Botanic Garden. But dig a little deeper (literally and figuratively), and you’ll find the reason for that slope: the “hill” is actually the remnants of a glacier. Its proper name is the Highland Park Moraine. It’s one of a series of five, collectively called the Lake Border Moraine System, found on the inland border of Lake Michigan.

MAP: The moraines of the region, including Highland Park Moraine.

A helpful map for visualizing the ups and downs of the moraines and the valleys in between. Source: Luman, Donald E., LiDAR Surface Topography of Lake County, Illinois. ©2013 University of Illinois Board of Trustees. All rights reserved. LiDAR map courtesy of the Illinois State Geological Survey.

Flashback to geology class: a moraine is a giant accumulation—a ridge—of clay/sand/gravel pushed forward by the leading edge of a glacier, then left behind as it shifts its motion and melts/recedes. Moraines vary in sizes and heights.

Glacial ice that once covered northern Illinois began to recede about 14,000 years ago, leaving the five moraines, like scallops in the landscape, with the oldest to the west, the youngest to the east.

Oldest and furthest west is the Park Ridge Moraine; to the east of it is the Deerfield Moraine. The lowland between them is the West Fork of the North Branch of the Chicago River. Third is the Blodgett Moraine; its creation dates back to 13,000-plus years ago. The valley between it and the Deerfield Moraine is the Middle Fork of the North Branch Chicago River. (The West Fork, Middle Fork, and Skokie Rivers come together to form the North Branch Chicago River.) Next comes the Highland Park Moraine, formed about 13,000 years ago; Green Bay Road was built along its crest. The Chicago Botanic Garden lies in the Skokie River Valley between the Highland Park and the Blodgett Moraines. Finally, a bit north and east lies the Zion City Moraine, the youngest of the five.

As if all that isn’t cool enough, the Highland Park Moraine is also a mini-section of the Eastern Subcontinental Divide: water from the Highland Park Moraine drains toward Lake Michigan (Great Lakes watershed) on the east side, and into the Skokie River Valley (Mississippi River watershed) on the west side.

ILLUSTRATION: A chart showing the geological specifications of the Highland Park Moraine.

Most people are familiar with the Continental Divide near the middle of the country; a secondary divide travels along our edge of Lake Michigan.

Planning & Planting

PHOTO: Lake sedge (Carex lacustris).

Sedges do well in spring rain/flood conditions, helping dissipate water through respiration.

Planning for the new bike/pedestrian path included much deliberation about the plants that were already growing at the site.

As construction neared, ecologist Jim Steffen reached out to Glencoe Friends of the Greenbay Trail and Betsy Leibson, who heads up the all-volunteer group, which is dedicated to restoring the sections of the Green Bay Trail bike path that run through their town (and ours).

Steffen offered to donate hundreds of sedges (Carex pensylvanica and Carex hirtifolia) that were in the path of construction—and then helped Leibson and volunteers dig them up for transplanting along their trail. The sedges are reportedly thriving. GFGT showed their appreciation in such an appropriate way: see their July 14 post about it here.

 


PHOTO: Bike.5 Reasons to Love the North Branch Trail Extension

  1. It’s safe (for all the bike riders who’ve wobbled in a vehicle’s wake on busy Lake Cook Road!).
  2. It’s ADA-accessible: 10 feet wide, smoothly paved, and appropriately inclined.
  3. It’s convenient for pedestrians heading to and from the Braeside Metra train station.
  4. It’s family-friendly for strollers and toddlers, and shepherding groups of kids toward the Garden.
  5. It’s the long dreamed-of and anticipated mile-long missing link between Cook County’s North Branch Trail and Lake County’s Green Bay Trail.

Become a Bicycling Member!

How smart is this? A special membership for those who ride their bikes to the Garden instead of driving. With plenty of perks included (discounts, member magazine, tax deductibility), but sans parking privileges, it’s a sensible and cost-efficient (just $50 annually) way to show your support for the Garden.

PHOTO: Happy bikers.

Become a bike member of the Garden!

A bike membership makes a great gift for the bikers in your life, too.

Check it out here!


©2014 Chicago Botanic Garden and my.chicagobotanic.org

Damselflies 101

Carol Freeman —  September 6, 2014 — 4 Comments

The Chicago Botanic Garden is a great place to find damselflies. You can find them in every location here, and different locations will often yield different species.

PHOTO: Rare form of male Eastern Forktail damselfly.

This is the rare form of the male eastern forktail damselfly. You can see what looks like an exclamation point on its back, similar to the fragile forktail damselfly. ©Carol Freeman

For example, you might find stream bluets along the river and orange bluets hanging out on the lily pads. Most species measure about an inch in length and can be easily overlooked, but when you take time to slow down and search for these tiny gems, you will be rewarded with finding some of nature’s most beautiful hunters. Indeed, these tiny insects are fierce hunters—but don’t worry, as they neither bite nor sting humans. Their preferred food choice is other, smaller insects (including mosquitoes).

The main differences between dragonflies and damselflies are their size and wing positions. Damselflies, in general, are smaller, and hold their wings over their abdomens. Dragonflies tend to be larger, with a heavier body, and hold their wings out to the side.

The most common species around here is the eastern forktail damselfly. Identifying them can be tricky, as they come in several different varieties! The males and females look very different from each other, and the females change color as they age.

PHOTO: Male Eastern Forktail damselfly.

This is the most common coloring for the adult male eastern forktail damselfly (Ischnura verticalis). Note the blue on the end of the abdomen. ©Carol Freeman

PHOTO: Immature female Eastern Forktail damselfly.

This is a young female eastern forktail damselfly (Ischnura verticalis). She will turn a light, powdery blue as she ages. ©Carol Freeman

PHOTO: Female Eastern Forktail damselfly.

This is the most common coloring of the adult female eastern forktail damselfly (Ischnura verticalis). ©Carol Freeman

 

PHOTO: Male Fragile Forktail damselfly.

This is an adult male fragile forktail (Ischnura posita) — similar to the rare form of the eastern forktail. Keep your eyes open for this one, as they often fly near the eastern forktails. ©Carol Freeman

I like to get out early in the morning. The light is low, there is often dew, and the insects move a bit more slowly until they warm up. One of my favorite places in the Garden to photograph damselflies is in the Dixon Prairie. They like to hang out on the grasses there. Walking slowly on the path next to the plants, you will see what look like tiny flying sticks. Damselflies will often congregate in one area and, if disturbed, sometimes land just a short distance away. I like to use my 105mm or 200mm macro lenses to photograph these beauties. They will fly until the first really hard frost. There are dozens of species native to this area—all of them beautiful and fierce hunters. 

PHOTO: An adult female Eastern Forktail damselfly eating another insect.

Here is an adult female eastern forktail damselfly with her catch of the day. ©Carol Freeman


©2014 Chicago Botanic Garden and my.chicagobotanic.org

I am a July 2014 graduate of the National School of Landscape Architecture of Versailles in France, where I studied landscape architecture for seven years. I like this field because each project is different, and we can work on different kinds of spaces and scales; park and garden projects, or public space (square, street, district) studies for cities or larger territories. For my diploma, I worked on a landscape project for salt marshes in a huge area in the south of France.

PHOTO: Maxime Soens with the Fruit & Vegetable Garden terraces.

Standing on the bridge to the Fruit & Vegetable Garden; terraces and apple trees as a backdrop

I chose to do an internship here in the United States to learn more about plants and the American garden culture. This internship was initiated by the French Heritage Society, which has organized student exchanges between France and the United States for the past 30 years. I am here through a partnership with the Chicago Botanic Garden and the Ragdale Foundation, an artists’ community in Lake Forest.

I spent four weeks at the Regenstein Fruit & Vegetable Garden at the Chicago Botanic Garden working under that garden’s horticulturist, Lisa Hilgenberg. The team was great, and it was a really interesting experience to discover new vegetable species or new ways of maintenance. I have done similar internships before, like in the kitchen garden of the King in Versailles, or at Potager du Roi, but those were not educational vegetable gardens like the one here in Glencoe. The Chicago Botanic Garden is wonderful, and I appreciate particularly the quality and variety of its vegetal compositions. Generally, I’m very impressed by the work of American gardeners and landscape architects. They are perfectionists. 

PHOTO: The Grand Square of Potager du Roi.

The Grand Square of Potager du Roi. This three-hectare garden is composed of 16 squares bordered by espalier pear trees that are grown upon support frameworks. The majority of the garden’s vegetable plants is located within this area. « Potager du Roi » par Paris HistoireTravail personnel. Sous licence CC BY-SA 3.0 via Wikimedia Commons.

When I was not at the Chicago Botanic Garden, I worked at the Ragdale House to help with the volunteer gardeners. It’s a historic garden designed by the famous architect Howard Van Doren Shaw at the end of the nineteenth century. Uses of the garden have changed since then, and there are different kinds of challenges for the maintenance today. I was asked to design a project for the garden as part of my internship. During this process, the prairie was a source of inspiration for me, as it is a typical landscape of Illinois. My main goal was to find a new link between the house, the garden, and the prairie, and I chose prairie native plants for a lower maintenance in the flower beds.

PHOTO: Maxine's presentation for Ragdale.

The finished project/proposal for Ragdale is displayed at its Benefactors’ Garden Party. Low-maintenance native plants create a link between the house, the garden, and the prairie.

My stay at Lake Forest and Glencoe was an enriching exchange with the gardeners and the artists, and I hope that it will be the beginning of a new relationship in the coming years.

Maxime Soens
Paysagiste DPLG


©2014 Chicago Botanic Garden and my.chicagobotanic.org