Today we explored two prairie sites, one which had been burned recently and one which had not. It was startling to see the dramatic difference in the plants inhabiting each site, and the mosaicism that shows in the landscape of the burned site.

ALF West, the site that hadn’t been burned, was overwhelmingly dominated by non-native brome grass, while at the site that had burned, ALF East, we observed more diversity in grass species, as well as a very noticeable absence of the brome grass where it looked like the site had burned. We also noticed the impact of the fire on shrubs and trees in ALF East, and compared that to the new saplings coming up in ALF West. There were two Echinacea angustifolia plants that we observed in ALF West, growing in the gravel on the side of the road.

Red flag warning for our study area and much of Minnesota. What does this portend for the prescribed burning season?

https://www.dnr.state.mn.us/forestry/fire/firerating_restrictions.html

as asserted in Munroe (2023)?

This is going to be the main agenda item for team Echinacea meeting until the snow melts.

• Is Minnesota getting
  • thinner?
  • narrower?
  • skinnier?
  • shorter?
• Will we need to gps every single Echinacea plant again?
  • do we need to do demo too?
  • Maybe instead of annually, we can re-map each plant once per decade
• Do Echinacea plants feel the squeeze?
  • Does the squishiness make Echinacea happy?
• Are ground-nesting bee nests getting deeper?
• Why don’t we have any snow?

Echinacea Project 2023

Undeclared, Carleton College, 2026

Pronouns: He/him

Research Interests

I want to study biology and learn more about plant science.

Statement

I am from Houston, Texas.

In my spare time I like to play the trumpet and play games.

Echinacea Research Project

Introduction

The goal of my externship was a research project about Echinacea where I asked two questions and then conducted a study. The first question is does having taller head height increase pollination rates by insects in Echinacea. My second question is does having more heads increase or decrease pollination by insects in Echinacea.

Background

Echinacea is insect-pollinated mainly by bees and other studies I found have shown that in plants like C. behrii and V. thapsus taller heads are more likely to be pollinated because they are more visible to pollinators. Since we don’t know if head height plays a similar role in Echinacea I am conducting this study to see if there is any correlation between head height and pollination rates in Echinacea.

Another study I found saw more heads leading to greater pollination rates. However, Echinacea is self-incompatible, meaning it can not pollinate itself, unlike the plants in that study so its possible that if an insect stays at a single Echinacea plant with more heads instead of moving on to other plants it could actually hurt its pollination rate. This led me to my second research question to determine if there is a correlation between number of heads and pollination rates in echinacea.

Methods

I used data from a sample of about 229 heads that were put through a data collection process aimed at separated and analyzing the achenes in Echinacea heads. Achenes are the fruit that contain seeds in Echinacea heads so by analyzing if they contain seeds or not we can gather pollination data for this experiment. In the first step of the process we cleaned the heads for achenes. Then we rechecked our first count for accuracy and scanned the achenes into the computer for counting. Lastly, we randomized our achenes, separated them to be x-rayed, and classified them to see which achenes contained seeds giving us our pollination rates.

Question 1

After the data collection process the data was compiled into spreadsheets that were uploaded into R. I put the data on a scatterplot with head height vs pollination rate to create a regression line that had a positive correlation but was also very scattered. To see if that correlation was significant I conducted a linear regression analysis and found that it was significant so taller head height does seem to be related to higher pollination rates.

Question 2

I used boxplots to visualize this data with number of heads for an individual Echinacea plant vs average pollination rate and the pollination rate seems to go up as number of heads increase, the opposite of what I was expecting with self-incompatibility. I then conducted an ANOVA test and found that the difference in average pollination rate by number of heads was not significant so number of heads does not seem to have an effect on pollination rates.

Conclusion

My results gave a positive correlation between head height and pollination rate and no correlation between number of heads and average pollination rate. However, a big limitation to my study was the sample size, especially for question two. Only having one data point for the 5 and 7 heads categories could have a large effect on the data. Lastly, since this was an observational study we can only infer correlation not causation so someone conducting an actual experiment would be a good direction to go in the future.

Acknowledgements and Bibliography

Bibliography-

• Dickson, C.R., Petit, S. Effect of individual height and labellum colour on the pollination of Caladenia (syn. Arachnorchis) behrii (Orchidaceae) in the northern Adelaide region, South Australia. Plant Syst. Evol. 262, 65–74 (2006). https://doi.org/10.1007/s00606-006-0472-3
• LORTIE, Christopher J., and Lonnie W. AARSSEN. “The Advantage of Being Tall: Higher Flowers Receive More Pollen in Verbascum Thapsus L. (Scrophulariaceae).” Écoscience 6, no. 1 (1999): 68–71. http://www.jstor.org/stable/42901102.
• Ohashi K, Yahara T. Effects of variation in flower number on pollinator visits in Cirsium purpuratum (Asteraceae). Am J Bot. 1998 Feb;85(2):219. PMID: 21684905.
• Wagenius S, Lyon SP. Reproduction of Echinacea angustjfolia in fragmented prairie is pollen-limited but not pollinator-limited. Ecology. 2010 Mar;91(3):733-42. doi: 10.1890/08-1375.1. PMID: 20426332.

Thanks to Wyatt and Abby for helping me with data collection, Stuart for helping me develop ABTs and to the National Science Foundation for providing funding.

Materials that were used for my project can be found in the filepath: ~/Dropbox/ccExterns2023/conlanRamirez

Presentation

Members of team Echinacea went back to Minnesota to do some final field work and winterization of our field station. We had fantastic weather for field work but northerly winds brought chilly temps by the end of the week and reminded us that winter is near . Here are some updates from all we got done these past few days!

Seed Add

 We added seeds to 84 experimental transects at 36 sites for our seed addition experiment, which measures the effects of prescribed fire on seedling germination and emergence in Echinacea. We made quick work and were able to get this done in just 1 day plus an extra morning!

Prescribed Burning and Broadcasting Seed

We got two solid days of good burn weather– more than any of us predicted! Over this window we burned six units, including the production plot, a few oak litter areas, Jean’s prairie garden, and the southeast hill. After all this burning, we broadcasted native seed collected by the team this summer. We’re excited to see what happens in these units next year!

Return Achenes to Remnants

Every summer we harvest a subset of Echinacea heads from remnant sites to assess fitness. In order to ensure that we are not disrupting these populations, we later return the achenes to their maternal plants in a way that mimics natural dispersal. On this trip, we visited many small sites, where this process is essential as well as a few bigger ones.

Woody Encroachment Pilot

I tested out methods for my research project looking at the effects of Sumac encroachment on Echinacea fitness and mortality. I collected height and spatial location information on Sumac plants in order to quantify encroachment. In an encroached site like Tower, this process was no walk in the park…

Post- Summer Sleuthing

When mistakes during summer data collection happen, it takes some investigating to figure out where we went wrong. On this trip, we revisited plants with issues from demographic data collection AND we found a P02 plant that was never harvested during the summer!