May 2013 Archives

I drove from the Chicago Botanic Garden to our field site in western Minnesota hoping for a window of appropriate burning weather on Thursday afternoon or Friday afternoon. I also brought 297 Echinacea seedlings to plant as part of an experiment that investigates hybridization between native and non-native Echinacea. Several gallons of side-oats grama grass seed were waiting to be hand broadcast at two sites after the burn.

Why burn?
We want to burn our large Echinacea "common garden experiment." In this abandoned field we have planted about 14000 individual Echinacea plants, starting in 1996, and measured their growth and flowering every year. We have burned this ~6 acre plot every other spring from 1998 to 2008. The weather didn't cooperate in 2010, so we burned in 2011. We are trying to burn this year! Burning in the spring really increases the chance that an Echinacea plant will flower. We are planning a big crossing experiment this summer, so we want as many plants to flower as possible. Also, burning sets back the weeds--and that is a good thing.

Here's the quick recap of major activities.
1. Packing
2. Driving to MN
3. Preparing to burn
4. The burn
5. Seeding after the burn
6. Preparing to plant
7. Planting
8. Seeding the phenology plot
9. Driving to IL

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Dwight makes sure the fire stays where it belongs

Read the gory details...

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Hello again!
This past week I was given the chance to present my findings from my project this quarter at a research expo held at Northwestern. I used a poster (attached) as a visual aide to help compare the trends and correlations observed between the frequency of fire and the presence of Echinacea on ant diversity in the two sites, SPPE and SPPW. It was a great experience to be able to talk to others about what I have been working on and getting to see what my classmates at Northwestern have been researching too!
linkingants3.pdf

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There was one project we did not get to this year. In the summer of 2012, field intern Kelly Kapsar observed flowering times for Echinacea in burned and unburned areas of the Staffanson prairie preserve. At the end of the summer, she collected the flowering heads in order to assess the relationship between flowering time and seed set. Various students have worked on aspects of the project. In November, Mindy Runge and Ale Mendoza (Lakeforest College) extracted and weighed achenes (click here to see their poster). In December, Marie Schaedel (Carleton College) weighed additional achenes and assessed our methods of judging whether an achene is full or empty (click here to read her results ). Most recently, Jill Pastick (Lakeforest College) finished extracting achenes and helped organize the collection.

These steps (extracting and weighing achenes) allow us to draw a relationship between flowering time and seed set (i.e. the proportion of full vs. empty achenes). The next step of this study will be to germinate the achenes and plant them in the field. Unfortunately, that will have to wait until next year. In the meantime, the collection of weighed and organized achenes will be stored in the freezer.

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On Thursday, 23 May 2013, Brad Dykstra and I (Amy Dykstra) helped Stuart and his parents burn the common garden (C1). The burn was slow and thorough. Some photos follow.
P5232408.JPGWe started at the south end of the plot.

P5232414.JPGAt times, the fire was quite smokey.

P5232428.JPGHere, Stuart lights vegetation in the ditch along the west side of C1.

P5232451.JPGWe also burned the '99 South plot.

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Throughout the past semester, I have been interning in Dr. Stuarts lab, working with Echinacea angustifolia. I performed two experiments during my time there. One comparing the differences in growth for two pre-germination methods. For this experiment, I measured the hight of the plant on three separate dates in order to determine the plant success for five cohorts.

No analysis was performed on Cohorts 4 and 5 because there was no growth for any of these plants. All plants with a height of 0 at the last day of measurement were considered dead.

We performed an ANOVA using R to compare the mean heights of Cohorts 1 and 2 at each age at which they were measured. After performing analysis for Cohorts 1 and 2, we found that there was no significant difference in the heights of the plants germinated using the Blotter method than those plants germinated using the Agar method. These results were similar for each of the three ages at which the plants were measured: 14, 28, and 35.

In addition to the three measurements performed on each of the plants, I also chose a single day in which to measure all of the plants. On March 19, I measured each of the 418 plants. We performed an ANOVA analysis on the mean heights of living plants on this single day in order to see if there was a cohort effect on the measurements. We found that there was no difference in measurements of the plants among treatments, but that height does differ among cohorts 1 and 2, according to a linear model, which we had expected.

There is much more analysis which can be done with the data collected and which we hope to do in the future, including comparisons for rate of emergence, timing of emergence, and survival of individual plants.


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This image shows a dish of achenes pre-germinated using the blotter method.

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This image shows a dish of achenes pre-germinated using the agar method.

I will also be working on the analysis of my second experiment throughout the summer, involving the comparisons of plant growth and plant morphology for four crosses between Echinacea angustifolia and Echinacea pallida. So keep an eye out for updates!

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Last week I gave a public presentation describing my M.S. thesis with the Echinacea Project. After two summers of field work and eight months of data analysis and writing, I managed to succeed in passing my defense. I have included a link to my presentation slides. They do not include much in the way of explanatory text, but they have an abundance of pictures and graphs along with a dash of poetry.

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ThesisPresentationFinal.pdf

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