Carleton Externs – Sarah’s Final Update

Hello flog, one last time!

Today marks the end of my three weeks here on Team Echinacea, and I’m certainly sad to say goodbye! Nevertheless, it was exciting and rewarding to culminate this externship with a week of data analysis, poster creation, and presentation of findings to the team. While Tris chose to analyze data from Michael’s Echinacea pollen limitation experiment, Julie and I decided to delve into the worlds of Liatris aspera and Solidago speciosa, two other Asteraceae common to prairie ecosystems. Lea has been working with these species for her PhD project over the past few years, studying how timing and location of flowering influences reproductive success, so she was a great help as we commenced our analysis!

After having meticulously cleaned, counted, and classified innumerable Solidago and Liatris flowering heads, Julie and I wondered how the vast differences in head count between these two species may impact each plant’s fecundity (when Liatris plants generally have 10-20 heads, and many Solidago plants have hundreds or even thousands) . Further, knowing that human populations have largely suppressed the occurrence of natural fires in today’s prairies, we were also interested in analyzing the effects of prescribed burns on these common prairie species. We put these two questions together in our data analysis by forming a statistical interaction model–one in which the effect of fire would interact with the effect of flowering head count to influence reproductive success–and fitting it to our Liatris and Solidago data. Interestingly, we did not uncover the same results for these two closely-related plants! For Liatris, the interaction model was highly supported by our data: the head count of plants seemed to have more effect on seed set (a measure of fecundity) in plants that had not been recently burned than in plants that had been recently burned. Yet, for Solidago, this pattern was not present. Our findings suggest that prairie management strategies, of which prescribed burns are an integral part, should carefully consider the species composition of a prairie before burning, because different species may react to burn treatment in different ways. Check out our poster, attached here, for a more detailed analysis, as well as plots of our models!

Before I sign off, I want to send a huge ‘thank you’ to every member of Team Echinacea! This opportunity was incredibly influential for me–this was my first real research experience, and I learned so much about ecology, networking, career paths, data collection, statistics, and more. I had an amazing time, and I hope to see some team members again someday!

Thank you again,


PDF version below:

Soliatris2018 Poster

Carleton Externs – Tris’s Final Update

Hi flog,

Wow! These last three weeks passed by super quickly! While the first two weeks were focused on seed cleaning, seed counting, and x-raying, we spent this past week on our independent projects. But that’s not to say this week was easy! In the past 5 days, I wrote exactly 900 lines of code in R to generate the figures and perform the analyses.

To get at how current pollen limitation affects Echinacea growth and future fitness, I performed analyses testing differences in plant traits between pollen exclusion, pollen addition, and open pollination treatments. I did not find evidence that pollination treatment affected either growth or fitness, which indicates that current pollen limitation will not benefit Echinacea in the future. This could be because Echinacea is not resource limited or because the cost of seed production is negligible.

Many thanks to the members of Team Echinacea who helped guide me through this process and made working in the lab such a pleasure!



Link to Poster

Aphis echinaceae at Carleton’s Fall Poster Symposium

The aphids were a hit at Carleton’s Summer Research Symposium.

At the Carleton College Summer Research Symposium on October 26th, I presented a poster on my work on the aphid addition/exclusion experiment. Over the summer, I administered the aphid addition and exclusion treatments for the experiment and collected data on leaf senescence and herbivory on plants in the study. Since August, I have been developing an aster model in R to analyze differences in fitness between these two experimental groups. Preparing the aster model for my project was quite a bit of work, but I learned more about R, statistical analysis, and plant-herbivore interactions in the process. Interestingly, Aphis echinaceae has not had an impact on plant fitness over the 8 years of the study.

I am excited to see how the experiment progresses in the coming years, and how the addition of data on seed set affects the results of future fitness models. Quite a few visitors to the symposium were also interested in the results of my analysis and my experience working with the aphids. It was a pleasure to represent the Echinacea Project at Carleton and to have a chance to share the fantastic work the team did over the summer.

Riley’s Fall Semester Update

Hello Echinacea folks! After a great summer at the Echinacea Project, I returned to Gustavus to work on the morphological and physiological data I collected at experimental plot 7. In my time at Gustavus so far, I wrote a proposal for my project so I can analyze my data and undertake a senior honors project under familiar Echinacea advisors Pamela Kittelson, Stuart Wagenius, and Sanjive Qazi. I have also worked on a methods section for my final honors paper and made a poster (attached below). In addition to my project, this fall I have been working on a project to implement composting and sustainable practices in Saint Peter restaurants and a project analyzing microRNA-mediated stress response in smooth cordgrass. The next steps for my honors project are to write up an introduction and do statistical analysis over our January-term. I will be performing aster and cluster analyses and am really excited to get back into some R coding! echinaceaPoster1_Thoen

A Farewell to Aphids

This morning the much-diminished Team Echinacea (Stuart, Kristen, Lea, Michael, and I) gathered at the Hjelm house to start the day. Lea went to Staffenson Prairie Preserve to measure the flowering phenology of Liatris and Solidago plants. Michael and Kristen began to prepare experimental plot 8 for management in the coming year. The team will treat rogue Ashe trees and collect and broadcast the seeds of several prairie plant species in this plot. This is part of an ongoing effort to ensure that the plant community within the plot is consistent throughout.

Meanwhile, I assessed the leaf damage and senescence of plants in the aphid addition/exclusion experiment in p1. This was the final component of the fieldwork involved in this experiment for the season, and the last step in my independent project before I begin statistical analysis. The next step is to gauge fitness differences between plants in the aphid addition and exclusion treatments by constructing an aster model. While it was exciting to finish this aspect of the project, I will miss spending time with my Aphis echinaceae friends.

Over lunch the team prepared for inclement weather by sharing our experiences of intense weather events. After that, Kristen presented an update on her master’s project. She shared some intriguing preliminary results about the nesting preferences of native ground-nesting bees. We are all looking forward to the results of her study! Due to the rainy weather, the team was ready to call it a day after Kristen’s presentation. We held a short meeting to plan next week’s schedule and then headed home for the weekend.

Manuscript Submitted (Finally!)

Hi Flog!

I just wanted to give you all a quick update on the heritability of flowering time project I have been working on (for a long time)! We collected data on the phenology of the plants at experimental plot 2 during the summers of 2015 and 2016 and the phenotypes of those individuals to the phenotypes of their parents in 2005. Jennifer Ison began this project as a part of her dissertation in 2006 and I was lucky enough to pick it up when the individuals in experimental plot 2 really began to flower.

Since we collected data in ’15/’16 we have been working on analyses to determine the amount of variation in flowering time that is heritable. We found that there is substantial heritability for both onset of flowering and duration of flowering. Both of these traits are critical in describing the synchrony of an individual compared to the population and for determining the number of mating opportunities an individual will have in a season.

Today we submitted the manuscript that describes these results to Evolution. Drafting this manuscript has been an excellent learning opportunity for me and I have been lucky to work with some amazing scientists and writers. Thank you to my co-authors: Jennifer Ison, Stuart Wagenius, Frank Shaw, and Ruth Shaw.

2017 update: Echinacea pallida flowering phenology

Anna and Will decapitate a plant. It’s Echinacea pallida which is not native to Minnesota.

Echinacea pallida is an Echinacea species that is not native to Minnesota. In July 2017, we identified 100 flowering E. pallida plants with 222 heads that were planted in a restoration at Hegg Lake WMA. Every year for the past several years, we have visited the E. pallida plants, taken phenology data, and chopped off their heads. On July 7, 2017 when we collected the data, the maximum male row was 19, meaning flowering started about 19 days earlier–June 18, 2017. E. angustifolia in the remnants started flowering on June 24, about a week later. 17 of the 222 E. pallida heads were still buds on 7 July, so these plants would have continued flowering for awhile.

We went back to check if we missed any heads on 31 August and found two. They were done flowering, but hadn’t dropped seeds.

Start year: 2011

Location: Hegg Lake WMA restoration

Overlaps with: Echinacea hybrids (exPt6, exPt7, exPt9),  flowering phenology in remnants

Physical specimens: 222 heads were cut from E. pallida plants and likely decomposed. We brought two heads back with us to Chicago.

Data collected: A csv in ~Dropbox/remData/105_assessPhenology/phenology2017 with tag, row number the male florets were at on July 7, 2017 for each head, and initials of the data collector.

GPS points shot: We shot points for the 100 flowering E. pallida plants.

Products: In Fall 2013, Aaron and Grace, externs from Carleton College, investigated hybridization potential by analyzing the phenology and seed set of Echinacea pallida and neighboring Echinacea angustifolia that Dayvis collected in summer 2013. They wrote a report of their study.

Previous team members who have worked on this project include: Nicholas Goldsmith (2011), Shona Sanford-Long (2012), Dayvis Blasini (2013), and Cam Shorb (2014)

You can find more information about Echinacea pallida flowering phenology and links to previous flog posts regarding this experiment at the background page for the experiment.

2017 update: Flowering phenology in experimental plots

This year, the number of flowering plants in our main experimental plot (exPt1) dropped in half compared to last year. This might be due to the lack of a burn in the prior fall or spring. Plot 2 (exPt2) had about the same number of heads in ’16 & ’17.

In exPt1, we kept track of approximately 72 heads. The peak date was July 19th. The first head started flowering on July 2nd and the last head finished up on August 21st. In contrast, we kept track of 1076 heads in exPt2, about 140 more than last year! The peak date for these Echinacea was a bit earlier, July 13th. exPt2 heads also started and ended earlier (June 22 – August 19).

We harvested the heads at the end of the field season and brought them back to the lab, where we will count fruits (achenes) and assess seed set.

Flowering schedules for 2017 in exPt1 and exPt2. Black dots indicate the number of flowering heads on each date. Gray horizontal line segments represent the duration of each head’s flowering and are ordered by start date. The solid vertical line indicates peak flowering, while the dashed lines indicate the dates when 25% and 75% of heads had begun flowering, respectively. Note the difference in y-axes between the two plots. Click to enlarge!

Start year: 2005

Location: Experimental Plots 1 and 2

Overlaps with: Heritability of flowering time, common garden experiment, phenology in the remnants

Physical specimens: Harvested heads from both experimental plots are in the lab at CBG. The ACE protocol for these heads will begin soon.

Data collected: We visit all plants with flowering heads every 2-3 days starting before they flower until they are done flowering to record start and end dates of flowering for all heads. We managed phenology data in R and added it to our long-term dataset. The figures above were generated using package mateable in R. If you want to make figures like this one, download package mateable from CRAN!

You can find more information about phenology in experimental plots and links to previous flog posts regarding this experiment at the background page for the experiment.



2017 update: Ridley’s next generation rescue

geneticRescueSlideIn 2017 Stuart and Lea relocated and measured 19 individuals of the 381 seedlings originally found. These plants had 1-4 leaves; the longest leaf was 32 cm. It should be interesting to see which individuals are hanging on!

Caroline Ridley established this experiment to compare fitness (recruitment and survival) of seeds originating from individuals with parents from three different backgrounds: 1. both from a large remnant population, 2. both from a small remnant population (not rescued), and 3. one from a large population and one from a small population (genetically rescued). Caroline sowed achenes in an experimental plot at Hegg Lake WMA and marked seedlings with colored toothpicks in May 2009.

Start year: 2008

Site: exPt 4 at Hegg Lake WMA

Overlaps with: crossing experiments qGen1, qGen2, qGen3 & recruitment experiment; INB1

You can find more information about Ridley’s next generation rescue and links to previous flog posts regarding this experiment at the background page for this experiment.

2017 Update: Echinacea hybrids — exPt 9

This summer, we measured open-pollinated hybrid Echinacea plants in experimental plot 9 at Hegg Lake. The table below shows the number of plants found alive during each search since the experiment started in 2014. Of the surviving plants in 2017, 90% had fewer than 3 leaves, the mean length of the longest basal leaf was 25 cm, and only six plants had more than one basal rosette. This year we searched for plants once then rechecked every position where we didn’t find a plant during our first search. No plants flowered this year.

Year / Event Number Alive % Original remaining % Of previous year
Planting (2014) 746 100
2014 638 85.5 85.5
2015 521 69.8 81.7
2016 493 66.1 94.6
2017 401 53.8 81.3

This experiment comparing the fitness of Echinacea hybrids with pure-bred E. angustifolia and E. pallida will give insight into the possible consequences of non-native E. pallida being planted in restorations in Minnesota, where E. angustifolia is the only native Echinacea.

Measuring at Hegg Lake

Start year: 2014

Location: Hegg Lake Wildlife Management Area — experimental plot 9

Overlapping experiments: Echinacea hybrids — experimental plot 6Echinacea hybrids — experimental plot 7

Data collected: Rosette number, length of all leaves, herbivory for each plant collected electronically and exported to CGData. Recheck information for plants not found was also collected electronically and stored in CGData.

You can find out more information about experimental plot 9 and flog posts mentioning the experiment on the background page for the experiment.