Embedded Files
Group Members and Roles
Group Members and Roles
Amaya Gab - Visual Director, Amanda McCall - Editor, Charity Bittinger - Documenter
Background Information
Prairies have been around in the United States for thousands of years and can include many different species of grasses as well as hundreds of forbs or flowering plants. Prairies are very resilient and adaptable to their environment’s climate and conditions due to their deep roots and underground stems. This aids the prairies in recovering from fires, frosty winters, floods, and adjusting to seasonal changes. Prairies are home to many different species of animals and more commonly grazers. There are three types of prairies: short-grass, mid-grass, and tallgrass. The most fertile and well-watered region, the tallgrass prairie, has been reduced to about 1% of its original area. This makes it one of the rarest and most endangered ecosystems in the world. According to the National Park Service, the largest remaining area still left unplowed is in the rocky and hilly region of Kansas called the Flint Hills (National Park Service, n.d.).
The prairie at Free State High School is a tallgrass prairie. It was planted in 2014 and was a collaboration between Free State High School and the University of Kansas. The prairie was a “restoration experiment”. It was planted in eighteen different plots, and three treatments were divided into them (grasses only, grasses and forbs, and grasses and 2x the forbs). Each treatment had six replicates spread among the prairie. It was and will continue to be used for research by students and people in the community. A group of students in their biology class was assigned to ask an objective question about prairies and choose one to base an experiment on. Our group asked “How do the different plant interactions in the prairie affect the height of the big bluestem grass?” We took that question and began experimenting at the Free State prairie to answer it. Our experiment would require protective gear such as jumpsuits and boots to protect ourselves from poison ivy and other similar plants. We would also need two meter sticks to measure the height of three big bluestems in six plots, so we would have many replicates, making our data more accurate.
The prairie was dense in the population of different species, so they were in constant interspecific competition for space, water, sunlight, and other resources. They were also constantly affecting each other’s growth directly because there were limited resources, and one or the other would deplete more of them, slightly depriving the other one. Grasses such as the big bluestem or Indian grass seem to consistently compete for space in prairies because they are very common. Not only are there direct effects, but like most other ecosystems, there are food chains. As we began our study, we also noticed that the plants in the Free State prairie were all autotrophs on a food chain and collected energy for themselves from the sun.
Prairie Rosinweed
Giant Blue Sage
Indian Grass
Description of Data Collection Methods
Before we were able to actually begin our experiment, we needed to put a plan together. Our goals for day one ended up extending to days two and three as well. We first hoped to collect three big bluestem height measurements from six different plots. We also wanted to identify and capture photos of any of the plants that shared plots with the big bluestem.
We put on some boots and headed out to the prairie. We began at plot one, and measured in the plots from west to east in the first row, then east to west in the second row. We measured the first three big bluestems that we saw in each plot. The visual director and documenter measured the big bluestems with meter sticks and recorded the heights on a sheet of paper. If we came across a grass that was taller than one meter, we stacked another on top to ensure we were collecting accurate measurements of the grasses. This was also when the editor was using the “Seek” app to identify and take pictures of the different plants accompanying the big bluestems. We spent our three workdays collecting the same data, and prior to closing the experiment, we walked around the prairie, making certain that our data was accurate, that we had all of the information we needed, and to make sure that we identified most of the species of plants growing around the big bluestems.
Qualitative Data and Observations
While out in the prairie, we noticed that the big bluestem was a much more vibrantly colored yellow, had more seeds, and was significantly taller in plots with grasses only. The stem of the big bluestem was not very thick, but it split into about three parts near the top. The tips of the grass were also very soft yet detailed. The other plants in plots with forbs were also radiant because they were actual flowering plants. The most common colors in the prairie were green, yellow, brown, blue, purple, and white. The big bluestem is a tallgrass plant that can reach 6-8 feet. These tallgrass plants grow in clusters together and are adaptable to climate changes, which makes them thrive in prairies all around.
Conclusions
Prairies contain hundreds of different species of grass and forbs. The big bluestem is very common in tallgrass prairies, and this is why our group was curious about how its surrounding plants affect its height and growth. Collecting this data was an overall simple process with three people. It was manageable in a short period of time because each of us were responsible for different tasks. One person could physically measure the height of the big bluestem, someone else could document the heights, and the other person could take pictures of the plants that surrounded the big bluestem in order to identify some of the different forbs in the plots.
We concluded that the big bluestem was significantly taller in plots that were grass seeded only. The average heights of the grass seeded only plots were 243 and 241 centimeters while the average heights in plots with forbs were 206 and 200 centimeters. The average heights in plots with 2x forbs were 195 and 213 centimeters. Compared to plots with any forbs at all, the big bluestem, in plots that were seeded with grasses only, was 30-48 centimeters taller. This suggests that the big bluestem is able to grow taller when surrounded by other grasses, and that grasses may absorb and use the same amount of resources. It may also suggest that forbs like rye/lemongrass engages in interspecific competition with the big bluestem, and limits its resources to grow. We have come to these conclusions because the evidence shows us the plots with only grass had significantly taller heights. We also think these are the interactions the big bluestem has with some of its surrounding plants because of what we have learned in biology about interspecific competition, direct, and indirect effects/interactions.
Daisies
Sennas
Rye/Lemon Grass
Next Steps
A source of error in this experiment may have been that we didn’t line the meter sticks up to the big bluestem well, and when we stacked the two meter sticks, there was no guarantee we would get exactly accurate numbers, so this may have altered the data outcome. We think we could have solved this error by using a tape measure instead of the meter sticks. We also noticed during the course of the data collection process that the “Seek” app was not identifying plants accurately because the pictures did not match. More research afterwards may have improved our accuracy in this case. Our biggest error was that we only measured big bluestem heights on the outlines of each plot because we did not want to step on other plants in order to measure in the center. Our height measurements may have been more diverse if we were able to measure deeper into the plots.
Despite our sources of error or inaccuracy in this experiment, we collected three big bluestem height measurements from each plot. This allowed us to calculate an average from each plot. We also collected data from six plots, meaning our data was replicated again when we measured plots of the same seed formula. We collected height measurements from two plots for each of the three different plot formulas.
To answer our question more scientifically, we might have to research how exactly each plant supports the big bluestem or how much of its resources are used by other plants, and those numbers may be helpful to explain our results in more depth.
Lastly, another interesting question we discussed was “How do other grasses in the prairie compare to the big bluestem?” This includes the Indian grass because it was also very common. This further exploration would help us understand the relationship, indirect effects, and direct effects between the big bluestem and Indian grass. Learning about different species in the prairie would provide us the opportunity to better understand the prairie as a whole.
Burnet
American Asters
Prarie Rosinweed
Variables
Our independent variable in our project is the different plot treatments in the prairie because they were the only things changed in the experiment.
Our dependent variable is the height of the big bluestem because it did depend on the Independent variable (plot treatments).
The control group was the plots with grasses only because without any forbs, it gave us an opportunity to compare results.
The experimental group was the plots with forbs and 2x the forbs because we were testing how the treatments affect the big bluestem height.
The constants were everything that stayed the same in the experiment like the weather, amount of sunlight, amount of precipitation, and more.
Our null hypothesis was the idea that the big bluestem growing in different plots would not affect its height.
Our alternative hypothesis is the opposite because this hypothesis is the idea that the big bluestem growing in different plots would affect its height.
References
Department of Biological Sciences, Ammann, R. L., & Nyberg, D. W. (2005, July 1). The American Midland Naturalist. Vegetation Height and Quality of Original and Reconstructed Tallgrass Prairies. Retrieved September 28, 2021, from https://eds.b.ebscohost.com/eds/pdfviewer/pdfviewer?vid=0&sid=5b4ea883-0753-46c4-a6d1-19d2840cc5cb%40sessionmgr103
Lawrence Free State High School & University of Kansas. (2015, September 4). Free State Prairie. Free State Prairie Lawrence Free State High School. Retrieved September 28, 2021, from https://freestateprairie.wixsite.com/mysite/about
National Park Service. (n.d.). A Complex Prairie Ecosystem. National Park Service. Retrieved October 12, 2021, from https://www.nps.gov/tapr/learn/nature/a-complex-prairie-ecosystem.htm
Page updated
Report abuse