Small remnant Echinacea populations may suffer from inbreeding depression. To assess whether gene flow (in the form of pollen) from another population could “rescue” these populations from inbreeding depression, we hand-pollinated Echinacea from six different prairie remnants with pollen from a large prairie remnant (Staffanson Prairie) and from a relatively small population (Northwest Landfill) in 2008. We also performed within-population crosses as a control. Amy Dykstra planted the achenes (seeds) that resulted from these crosses in an experimental plot at Hegg Lake WMA.
We sowed a total of 15,491 achenes in 2008. 449 of these achenes germinated and emerged as seedlings. Each summer, we census the surviving plants and measure them.
In 2021, Amy Dykstra and Team Echinacea found 33 basal plants and 2 flowering plants (1 with vertical development only and 1 with one head). These were the first plants to flower in this experiment! The plant with one head grew from an achene produced by a between-population cross between a Steven’s Approach maternal plant and a Northwest Landfill pollen donor. The plant with vertical development grew from an achene produced by a within-population cross between a maternal plant from Aanenson and an Aanenson pollen donor.
For more details and graphs, see this brief report:
Data collected: Plant fitness measurements (plant status, number of rosettes, number of leaves, and length of longest leaf), and notes about herbivory. Contact Amy Dykstra to access this data.
Samples collected: NA
Products: Dykstra, A. B. 2013. Seedling recruitment in fragmented populations of Echinacea angustifolia. Ph.D. Dissertation. University of Minnesota. PDF
You can read more about Dykstra’s interpopulation crosses, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.
In summer 2021, Amy Waananen continued the interremnant crosses experiment to understand how the distance between plants in space and in their timing of flowering influences the fitness of their offspring. This experiment builds on Amy’s study of gene flow and pollen movement in the remnants, asking the question of how pollen movement patterns affect offspring establishment and fitness. If plants that are located close together or flower at the same time are closely related, their offspring might be more closely related and inbred, and have lower fitness than plants that are far apart and/or flower more asynchronously. In other words, if distance in space or time is correlated with relatedness, we’d expect mating between more distant or asynchronous individuals to result in more fit offspring.
To test this hypothesis, Amy performed crosses between plants across a range of spatial isolation (within the same population, in adjacent populations, and in far-apart populations) in 2020. With the team’s help, she also kept track of the individuals’ flowering time to assess whether reproductive synchrony is associated with reduced offspring fitness, suggesting that individuals that flower at the same time are more closely related.
In 2021, Amy repeated the same hand crossing methods to assess the fitness consequences of outcrossing, this year on 44 focal plants.
To learn more about Amy’s project, check out this video created by RET participant Alex Wicker.
Amy collects pollen from Echinacea anthers
Start year: 2020
Location: On27, SGC, GC, NGC, EELR, KJ, NNWLF, NWLF, LF
Data/Materials collected: Style shriveling and seed set and weight from crosses, start and end date of flowering, coordinates of all individuals in the populations listed above
Another busy day for Team Echinacea! I started field work late this morning due to giving a talk at the virtual Evolution conference. Everything was pre-recorded, so it was great to enjoy listening to all the other talks in my session and learn about some new ideas related to gene flow. The title of my talk was “Outcrossing distance in space and time affects fitness in a long-lived perennial” — I’m planning to post the video on the Team Echinacea YouTube channel sometime soon so you can watch it anytime. While I was watching talks, the team was busy at work, doing phenology, shooting points, and nearly finishing flowering demo at all of the sites.
At lunch, we discussed team norms. Stuart floated the idea of turning the team norms into a blood pact sort of thing, but there was not much enthusiasm for the idea. It’s okay because one of our norms is that we want our work environment to be a “soft space” where everyone feels welcome to share their ideas, even if others don’t share the same opinion!
After lunch was the inaugural meeting of Team Dust. This is an exciting new initiative to investigate the effects of road dust on Echinacea. How much dust from gravel roads winds up landing on the plants on roadsides? Does this dust affect pollination or seed set? We intend to find out!
Here is a picture of several color-coordinated members of Team Dust.
Finally, we had our second official social gathering of the season. We ate bean burgers, air-fried fries, and (my personal favorite) Jean’s famous brownies! Delicious. We also drank and discussed several flavors of iced tea. Some of the words used to describe one of the teas included “turpentine”, “pine-sol”, “earthy”, and “savory”. Can you guess which one?
North winds and dry conditions persisted Monday (May 10) giving us an opportunity to conduct prescribed burns at p10, our experimental plot at West Central Area High School. In addition to being a home to 1400 coneflower plants and Amy W.’s gene flow experiment, these plots serve as an excellent educational resources for John VanKempen, high school science teacher at WCA and long-time member of Team Echinacea. John established an experiment in which each of the twelve 8 x 10 m plots is burned during spring, fall, or not at all. This will help us understand how fire affects the survival of Echinacea seedlings. John also uses these plots as a teaching resource for high school students at WCA.
Because this burn was conducted within Barrett city limits, John needed to get special permission from the mayor and fire chief. Plus members of the volunteer fire department needed to be present. So we met up with Jenny and DJ (from Barrett’s volunteer fire department) as well as TJ and Braeden (from Hoffman’s volunteer fire department). Before burning, Stuart, John, and I chatted with members of the volunteer fire department (who included several of John’s former students!). It was a great opportunity for us to learn from community members about their experiences with prescribed burns and their knowledge of prairies. For example, DJ owns a parcel of prairie just a little outside Barrett that was passed down from his father. TJ works for the DNR’s roving burn crew based in Elbow Lake. Talking with members of the fire department also gave us an opportunity to share a little more about the science behind why we conduct prescribed burns. We also shared information about the Echinacea Project’s research in west central Minnesota investigating how fire benefits native prairie plants as well as the diversity of insects, birds, and other species that call Minnesota’s tallgrass prairie home.
Oh and of course we partnered up with these local firefighters to burn 8 prairie plots! With dry fuel conditions and pretty heavy fuel in spots, we laid down wet lines and ignited a backing fire that moved slowly against the wind. In plots with primarily warm-season grasses, we secured the downwind (south) break and ignited down the east and west flanks before lighting a head fires that went screaming across the dry big bluestem. For plots with few warm season grasses and lots of brome, we chose to use exclusively backing fire in hopes of setting back the brome and achieving a consistent black across the entire plot. This technique worked well to achieve the desired result.
The final burn unit encompassed 3 adjacent experimental plots. The northernmost of these plots had dense big bluestem. We expected the fuel in this plot and gentle slope would produce quite a head fire. The plot did not disappoint. Members of local volunteer fire departments and the Echinacea Project worked together to secure the downwind fire break and blacken the downwind third of the burn unit consisting of three adjacent experimental plots. Once we had sufficient black and the east and west flanks of the unit were secured, we ignited a spectacular head fire that burned through the dense stand of big bluestem in less than a minute.
Thanks to Jenny and DJ from the Barrett volunteer fire department as well as TJ and Braeden from the Hoffman fire department for helping us conduct prescribed burns at the high school and sharing their experiences about fire and prairies in western Minnesota!
Temperature: 52 F Relative Humidity: 24% Wind Speed: 10 mph Wind Direction: NE Ignition time: 4:50 PM End time: 6:12 PM Burn Crew: Jared, Stuart, John, Jenny, DJ, TJ, Braeden
This summer I started a new experiment to understand how the distance between plants in space and in their timing of flowering influences the fitness of their offspring. This experiment builds on my study of gene flow and pollen movement in the remnants, asking the question of how pollen movement patterns affect offspring establishment and fitness. If plants that are located close together or flower at the same time are closely related, their offspring might be more closely related and inbred, and have lower fitness than plants that are far apart and/or flower more asynchronously. In other words, if distance in space or time is correlated with relatedness, we’d expect mating between more distant or asynchronous individuals to result in more fit offspring.
To test this hypothesis, I performed crosses between plants across a range of spatial isolation (within the same population, in adjacent populations, and in far-apart populations). With the team’s help, I also kept track of the individuals flowering time so that I can assess whether reproductive synchrony is associated with reduced offspring fitness, suggesting that individuals that flower at the same time are more closely related.
I ended up using 42 focal plants (two of which were mowed before I could harvest them) and a total of 167 sires. I planted 359 offspring from these crosses in November. Next spring and summer, I will measure the seedlings to collect data on emergence and growth. Seed set was lower than I wanted it to be (only ~20%, when I would have expected 60-70% based on compatibility rates in the remnants), so I will also likely perform more crosses in summer 2021 to shore up my sample size.
Crossing at scenic On 27
Start year: 2020
Location: On27, SGC, GC, NGC, EELR, KJ, NNWLF, NWLF, LF
Data/Materials collected: 40 seedheads, style shriveling and seed set and weight from crosses, start and end date of flowering, coordinates of all individuals in the populations listed above
Products: I planted the seeds from the crosses in a plot adjacent to P1 in November, as detailed in this flog post.
Monitoring
reproductive fitness in the remnant populations is a staple of Team Echinacea’s
summer activities. Understanding the reproductive success of plants in remnant
populations provides insight to a vital demographic rate contributing to the
persistence (or decline) of remnant populations in fragmented environments.
In summer
2019, we harvested 40 seedheads to study patterns of reproductive fitness in 8
remnant Echinacea populations (ALF, EELR, KJ, NWLF, GC, NGC, SGC, NNWLF) (the
same populations used where I studied phenology and gene flow). I randomly selected 1/3 of
flowering heads at each remnant to harvest. In addition, I collected all seedheads
from especially small or isolated remnants (specifically, GC, KJ, and the
cluster of plants just north of EELR).
In early
January, I dissected the seedheads. I extracted the achenes by row so that I
will be able to observe temporal variation in seed set within heads. Ideally,
next I will x-ray the achenes and assess seed set by observing the proportion
of achenes that contain embryos. However, the x-ray machine at the Chicago
Botanic Garden is currently out of service, so instead I may need to weigh or
germinate the achenes to see if viable embryos are inside.
Extracting achenes by row, so that I know which achenes resulted from florets that flowered early (i.e., at the bottom of the seedhead) or late (i.e., at the top of the seedhead). Tedious but possible!
Start
year: 1996
Location: Roadsides,
railroad rights of way, and nature preserves in and around Solem Township, MN
You can
read more about reproductive fitness in remnants, as well as links to prior
flog entries mentioning the experiment, on the background page for this experiment.
Small remnant Echinacea populations may suffer from
inbreeding depression. To assess whether gene flow (in the form of pollen) from
another population could “rescue” these populations from inbreeding depression,
we hand pollinated Echinacea from six different prairie remnants with pollen
from a large prairie remnant (Staffanson Prairie) and from a relatively small
population that we call “Northwest Landfill.” We also performed
within-population crosses as a control. Amy Dykstra planted achenes (seeds)
that resulted from these crosses in an experimental plot at Hegg Lake WMA.
Plants in the crossing plots were originally found as seedlings like this one
We sowed a total of 15,491 achenes in 2008. 449 of these
achenes germinated and emerged as seedlings. Each summer we census the
surviving plants and measure them. This summer we found 48 surviving plants.
None of these plants has flowered, but we think some of them are close! The
largest plant we measured had 4 leaves, the longest of which was 35 cm.
You can read more about the interpopulation crosses, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.
Start year: 2008
Location: Hegg
Lake WMA
Data collected: Plant
fitness measurements (plant status, number of rosettes, number of leaves, and
length of longest leaf), and notes about herbivory. Contact Amy Dykstra to
access this data.
Products: Dykstra, A. B. 2013. Seedling recruitment in fragmented populations of Echinacea angustifolia. Ph.D. Dissertation. University of Minnesota. PDF
In the fall of 2018, the Echinacea Project scientists came to West Central Area Schools (WCA) and mapped out twelve plots to transplant E. angustifolia into the following summer. The WCA Environmental Learning Center has 35 acres of restored prairie, making it a perfect place to plant experimental plot 10. During the summer of 2019, Team Echinacea planted over 1400 E. angustifolia seedlings into the 12 subplots. Three plantings were performed: the first was a planting organized by Michael and had offspring from exPt1, the second consisted of plants from Amy W’s gene flow experiment, and the third planting had offspring from the Big Event. All plants originate from Grant or Douglas County, MN. To test how different fire regimes affect fitness in Echinacea, folks from West Central Area will apply a fall burn treatment to four plots, a spring burn treatment to four other plots, and the remaining four plots will not be burned.
The team after planting the original cohort of Echinacea in experimental plot 10. It was a long day!
During science classes with John VanKempen, WCA high school students will assess the effects of differential burning regimes on the fitness of E. angustifolia. For the first time this fall, juniors in VanKempen’s classes used data they collected on plants to answer their own scientific inquiries. Students developed hypotheses, then measured various morphological traits on surviving Echinacea in the 12 plots. The students used the data they collected to create graphs based on their data. VanKempen plans to continually integrate these Echinacea experimental plots into his classroom lessons and hopes other teachers at WCA will utilize the experimental plots for student science projects.
Start
year: 2018
Location: West Central Area High School’s Environmental Learning Center, Barrett, MN.
Data collected: Planting and survival data for seedlings planted in summer 2019. GPS points taken for plots. Planting data is available in the Echinacea Project ~Dropbox/CGData/195_plant/. Contact John VanKempen for survival data taken by his students. GPS points are available here: ~Dropbox\geospatialDataBackup2019\planting2019\nailStakeWCA.csv
Products: High School Posters. Contact John
VanKempen for info.
Long time no see! I am a grad student at the University of Colorado now, but thankfully I have still had plenty of time to work on some Echinacea work. Last week I got to present at Botany in beautiful Tucson, Arizona 🌵.
First I presented a poster about fire and Echinacea demography. This is something we started in Chicago and Stuart, Amy Dykstra and I have been working on since. We used demap, the seedling search dataset, and the seedling recruitment experiment dataset to estimate vital rates (survival, flowering, and recruitment) within several Echinacea populations. We then estimated how these vital rates varied with fire. To see how these changes in vital rates affected actual population dynamics, we then constructed matrix models to estimate the average growth rates of several remnant populations under various fire frequencies. Finally, to see which demographic pathway was primarily responsible for changes in population growth, we decomposed the changes in population growth rates under different fire regimes into contributions from each vital rate’s response to fire. We used Bayesian modeling to estimate the vital rates. Stuart, Amy D. and I are putting the finishing touches on a manuscript for this project, so keep your eyes open!
I got some good questions from people at the conference. One is: would seed addition help bolster growth rates? Very interesting question – I think it probably would in populations with high juvenile survival, given that under these circumstances higher recruitment has the largest contribution to population growth. Another person asked about climate change and whether I thought the Echinacea range was likely to move north with warmer temperatures. I can’t answer that question but we did use climate data in our models; climate was warmer and wetter in our observation period than they were in the 100 years prior, and these covariates were featured in some of our models. It would be fun to incorporate climate change into estimates of vital rates and population growth.
I also gave a three-minute lightning talk to briefly present an idea I have had since I was in Chicago in 2017. Amy, Jennifer, Gretel, and Stuart have done some prior work looking at synchrony, mating opportunity, and mating success in Echinacea. I have been curious about whether populations exhibit nested structure in their flowering schedules, i.e., whether or not individuals which flower less often flower in the same years as plants which flower most often. There are some interesting potential consequences of deviation from non-nested structure. Hopefully I have time to study this in Colorado.
Also of note: Jennifer gave an awesome talk synthesizing a lot of the pollinator work done in the Echinacea system the last several years. It was great to see so many facets of Echinacea pollination discussed together. One of the most interesting parts of this talk was Mia’s poster, looking at the diversity of male pollen donors on bees, and how they varied by pollinator species. I remember when Laura was collecting this data in 2016. She was so good at wiping! Very cool to see final results for this project!
Otherwise, there were some great talks and posters. A couple of good ones: Joseph Braasch from Katrina Dluglosch’s lab at the University of Arizona talking about community shift with climate change and Jessa Finch (from CBG) talking about how gene flow affects early life stages of milkweeds. Maybe the best talk I saw came from a student in Julie Etterson’s lab at UM Duluth talking about how seed collections for restorations is artificially selecting for traits. Very cool question!
I’m glad I was able to make it out to the conference. Huge thanks to my advisors Brett Melbourne and Kendi Davies for allowing me to work on this project for the last two years. Also thanks to the BioFrontiers Institute at CU Boulder for providing me funding while I worked on this project, the United Government of Grad Students at CU Boulder for funding my trip to the conference, and friends at CU Boulder and Colorado State who allowed me to drive down with them and crash in their hotel rooms in Tucson. Hope to see everybody at ESA in Louisville, KY later this month, where I will have a poster about some of the non-Echinacea work I am doing in Colorado.
Dining in Tucson: Mexican food, no, waffles, yes!Ipomopsis longiflora I spotted on the drive back outside Taos, NM. The CO crew identified this plant with a key while I tried to find a gas station.
PhD Student, Ecology, Evolution, and Behavior, University of Minnesota
Research Interests
I’m interested conservation biology, especially as it relates to pollination, phenology, movement ecology, and population genetics. For my dissertation, I’m studying pollinator-mediated gene flow and trying to figure out under what conditions pollinators maintain connectivity between plant populations in fragmented environments. I think a lot about how the processes that drive how species respond to habitat fragmentation vary among spatial and temporal scales.
Statement
I grew up in a suburb of the Twin Cities and currently live in the silver city of St. Paul. I started working with the Echinacea Project as an intern in 2015. In my free time, I like to spend time outside, read, garden, and go on walks with my dog Gooseberry!
