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Liatris Update

Good news on the Liatris front: all hands-on work, from harvesting to x-raying, is complete! The process began in the summer of 2021 and involved lots of help from the field crew, wise, long-term Team Echinacea members, eager and efficient short-term members, and everyone in between.

Mia V and I were also able to complete data entry and data cleaning today, paving the road forward for analysis.

Now that we’re moving on to computer work, we came up with some primary questions to pursue (and some hypotheses):

  • Is there a significant difference in seed predation rates between burned and unburned and unburned remnants?
    • We suspect that predation will be higher in burned remnants because density of plants will be higher
  • Is there a correlation between seed predation rates and plant density?
    • We hypothesize that higher density will be correlated with higher rates of predation
    • We will use nearest neighbor as our measure of density
  • Is there a correlation between individual plant size and predation rates?
    • We hypothesize that larger plants will receive higher rates of predation
    • We will use number of flowering heads as our measure of plant size.

I’m now in the process of making plots to help us visualize the data we’ve collected, and soon we can begin to seek answers for our questions.

Because none of our questions at the moment directly relate to pollination, we don’t need to quantify seed set, which is the “classify” step. Using the x-rays to count how many achenes contain seeds is our method of determining pollination rates (seed = pollinated, no seed = not pollinated). This step will likely stay low priority for awhile, so don’t fret about the empty bar. All part of the plan.

Huzzah!

Liatris Update

Liatris aspera 2021 progress in the lab is steadily marching on. Thanks to the work of the Carleton externs last winter, we began Northwestern’s spring quarter essentially halfway done (only needing to do some brief back-peddling due to a change in protocol).

With the help of work study Mia V., cleaning, the process of removing the achenes from the flowering heads and gather data on achene-per-head count, is completely finished. Mia has also made excellent progress on randomizing, the step where we select a random sample of achenes to be x-rayed as well as quantify seed predation. We’re on track to finish randomizing later this week or next. Following that, we can x-ray the final batch of 56 liatris, allowing us to quantify seed set, and all the hands-on work for our 234 liatris from 2021 will be complete!

Priorities going forward:

  • Finish randomizing and x-raying for batch D
  • Complete randomization data entry and verification
  • Develop methods of data analysis to compare
    • Burned vs. unburned predation rates
      • In regards to density
      • In regards to number of heads per plant
  • Develop methods of classifying seed set from x-rays (low priority)

2021 Update: Aphid addition and exclusion

Team Echinacea continued the aphid addition and exclusion experiment started in 2011 by Katherine Muller. The original experiment included 100 plants selected from exPt01 which were each assigned to have aphids either added or excluded through multiple years. The intention is to assess the impact of the specialist herbivore Aphis echinaceae on Echinacea fitness.

In 2021, the aphid addition and exclusion project was conducted by Allie Radin with occasional help from other field crew members (often Emma Reineke). They located 26 living exclusion plants and 17 living addition plants. The experiment was conducted from July 9th to July 23rd, with the final visit consisting only of searching for aphids. No aphids were seen or moved in exPt01 this year.

Once again, there were very few aphids (actually, none) in exPt01. This is the second year in a row of missing aphids, raising other questions about where the aphids have gone, let alone their impact on the Echinacea plants. Allie and the team searched the experimental plot thoroughly to make sure no potential aphid hiding spot was left unturned. This included large plants from this year and last year, this year’s flowering plants, and plants which had aphids in previous years. Despite low aphid numbers, other insects such as beetles and thrips were present in the plot.

  • Start year: 2011
  • Location: Experimental Plot 1
  • Overlaps with: Phenology and fitness in P1
  • Data collected: Scanned datasheets are located at ~Dropbox\aphidAddEx\aphids2021
  • Samples collected: NA
  • Products:
    • Andy Hoyt’s poster presented at the Fall 2018 Research Symposium at Carleton College
    • 2016 paper by Katherine Muller and Stuart on aphids and foliar herbivory damage on Echinacea
    • 2015 paper by Ruth Shaw and Stuart on fitness and demographic consequences of aphid loads

You can read more about the aphid addition and exclusion experiment, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.

2021 Update: WCA Environmental Learning Center (ExPt10)

In 2019, Team Echinacea transplanted over 1400 Echinacea angustifolia plants from three local prairies to 12 plots at the West Central Area (WCA) High School, also known as exPt10. Since then, the West Central Area High School instructors and students have collaborated with members of Team Echinacea to gather data and plan the treatments of the plots, anything from burning to assessing plant fitness. In the fall, WCA students do an individual investigation using the Echinacea plots and then create a poster showing the process and conclusion of their investigation.

Having the Echinacea plots located at West Central Area School has provided many opportunities for the students to be involved in relevant research helping the Echinacea Project and doing individual projects. The plots at the school have also been used for additional research by Echinacea Project team members. Specifically, in the summer of 2021, graduate student Drake Mullett started a research project on prairie parasitic plants at exPt10 and will continue for the next few summers. Amy Waananen also continued an ongoing research project on Echinacea plants’ gene flow in exPt10. In May 2021, Team Echinacea conducted a prescribed burn at exPt10. Read more about the burn here.

  • Start year: 2018
  • Location: West Central Area High School’s Environmental Learning Center, Barrett, MN
  • Overlaps with: Gene flow in remnants, exPt10 Pedicularis planting, prescribed fire in plots
  • Data collected: Survival data for seedlings planted in summer 2019 from Amy W’s gene flow experiment, located in the cgdata bitbucket repository along with recheck data. Data from p10 will not be going into the SQL databases
  • Samples collected: None this year
  • Products: High school posters. Contact John Van Kempen for info.

What did we do in summer 2021?

Team Echinacea was busy this summer! Over the last few weeks, we have been posting updates on projects from summer 2021. Here is the complete list.

Experiments with 2021 updates:

2021 Update: Pollinators on roadsides

Tallgrass prairie once covered vast expanses of western Minnesota, but it has been almost entirely converted to agriculture, and only fragmented patches remain, often along roadsides. Insecticide use has also dramatically increased since the early 2000s, especially the use of neonicotinoids. In addition, pollinator populations are declining worldwide, likely due to this loss in habitat quantity and quality. In our study area, student Ben Lee found that pollinator habitat decreased by 6.8 km2 from 2006 to 2014.

More research is needed to understand how pollinator communities are changing in the fragmented prairies of western Minnesota. Native bees are critical for pollinating both native plants and commercial crops, and many plants depend on specialized pollinators, and so the decline of these pollinators may threaten the long-term survival of native plant populations as well as human food systems.

Therefore, the Pollinators on Roadsides study, also known as the Yellow Pan Trap project (YPT), is measuring changes in native bee diversity and abundance from 2004-2019 and investigating how the amount of agricultural land and grassland corresponds to the nearby bee community. One hypothesis is that all bee species are declining in abundance equally. Alternatively, some bee populations may be shrinking while others take advantage of the decreased competition and become more prevalent, which would change the community composition. We hope to find out!

This study is based on the original 2004 experiment by Wagenius and Lyon, who studied the relationship between characteristics of land and the abundance and diversity of pollinators. In 2004, 2017, 2018, and 2019, Team Echinacea set out yellow pan traps at 20-40 locations along roadsides in Solem Township which were surrounded by varying amounts of agricultural land. We collected the bees that fell into the traps and stored them at the Chicago Botanic Garden where patient volunteers pinned all the specimens. Many thanks to all the people who have contributed to this project over the past 18 years!

After a hiatus due to COVID-19, the Yellow Pan Trap project (YPT) is finally back on the road! In December 2021, we completed an inventory of all 1,988 YPT bees and delivered them in 8 cases to Zach Portman at the University of Minnesota. Volunteers Mike Humphrey and Anna Stehlik previously grouped the specimens by genus, and Zach will now identify the bees to species. Mia Stevens is working on a preliminary community analysis, and Alex Carroll is tackling the GIS landscape analysis.

Working with data that has been compiled by many different people over numerous years has been both exciting and challenging. Many thanks to intern Erin Eichenberger for leaving clear documentation from 2020. There are still a few problems that need to be resolved. During inventory, we discovered 9 pairs of duplicate specimen id numbers (SPIDs) from 2017, and the specimen labels will need to be changed. In addition, some of the date and trap numbers on the specimen labels were edited in pencil, and these should be cross-checked with the existing dataset.

  • Start year: 2004, rebooted in 2017
  • Location: Roadsides and ditches around Solem Township, Minnesota. GPS coordinates for each trap are in a Google Map which Stuart Wagenius can share as needed.
  • Overlaps with: Ground nesting bees
  • Data collected: All YPT data can be found in Dropbox/ypt2004in2017.
    • The most up-to-date files are in this folder: Dropbox\ypt2004in2017\yptDataAnalysis2022
    • The inventory list can be found here: Dropbox\ypt2004in2017\yptDataAnalysis2022\masterYptChecklist2021Verified.csv
  • Specimens collected: Eight cases containing 1,988 specimens were delivered to Zach Portman at the University of Minnesota for further identification.
  • Team members involved with this project: Mia Stevens (2020-2022), Alex Carroll (2021-2022), Erin Eichenberger (2019-2020), Anna Stehlik (2020), Shea Issendorf (2019), Mike Humphrey (2018-2021), John Van Kampen (2018-2019), Kristen Manion (2017-2018), Evan Jackson (2018), Alex Hajek (2017), and Steph Pimm Lyon (2004)
  • Products: Stay tuned!

You can read more information about the pollinators on roadsides project here.

2021 update: Pollinator fidelity and prescribed burns

This summer, Team Echinacea investigated whether there was a difference in pollinator fidelity in bees caught in eight burned remnant prairies and eighteen unburned remnant prairies. This experiment used the proportion of Echinacea angustifolia pollen carried by bees as they foraged on an E. angustifolia capitulum as a proxy for fidelity. 

The 2021 bee collectors included the entirety of the team, and bees were collected between June 28th and July 20th. Upon visiting a remnant prairie, we attempted to capture at least three bees of the taxa Augochlorella aurata, Agapostemon virescens, and Halictus spp. We removed the pollen from the body and scopae separately and created microscope slides which were later used to identify the species carried by the bees based on morphology. After wiping them of their pollen, the bees were released back to the sites where they were caught.

  • Start year: 2021
  • Location: 26 remnant prairies
  • Overlaps with: NA
  • Data collected: Each bee was assigned a unique number from 101 to 192, and the scopae or body pollen was differentiated with either a B or an S (ex: 101S and 101B). The site, taxa, Echinacea tag number, date, and time of day were recorded for each bee caught. All heterospecific flower species in bloom at the site on the day it was visited for bee collection were noted on a spreadsheet.
    • The data collected on the bees can be found here: https://www.dropbox.com/scl/fi/tuwkxqj2tau1ov33h7cgd/Dropbox-bee-data.xlsx?dl=0&rlkey=7wf2wxhy3w13qrt5xpk1pamsp
    • The form containing the blooming heterospecific flower species can be found here: https://www.dropbox.com/scl/fi/k94j5vrhhj9m9xtjm69gl/Heterospecific-flowers.xlsx?dl=0&rlkey=drds57bfzj7c2wo9zcy1g2xh0
  • Samples collected: 92 bees were caught and released and 89 were released back to the site where they were caught. 184 microscope slides were created with the pollen collected from the bees. These slides are being stored in Dr. Ison’s lab at the College of Wooster. A sample of each of the heterospecific flowers found at each was collected to create a pollen library. The slides created for the pollen library are also stored in Dr. Ison’s lab at the College of Wooster.
  • Products: Report to be compiled this spring!

2021 Update: Cirsium hillii fire & fitness

We are still monitoring the fate of the lone patch of Hill’s thistle at Hegg Lake WMA. It is the only patch in our study area, as far as we know. On 8 September 2021, Jared & Stuart used a stake file to find corners of the plot that was shot in 2014. We flagged the corners and did not see any flowering rosettes within. We shot coordinates for five basal rosettes. Two rosettes were outside of the plot near the SW corner. We scanned nearby and saw no more rosettes outside the plot. One Asclepias viridiflora plant was flagged within the plot. I regret I took no photos.

  • Start year: 2014
  • Location: Hegg Lake WMA
  • Data collected:
    • GPS coordinates ~Dropbox\geospatialDataBackup2021\convertedTXT2021\CIRSIUM_20210908_DARW.txt
    • notes. see file 2021-09-08notesCirsiumHillii.pdf
  • Samples or specimens collected: none
  • Products: none

You can find more information about our experiment on how fire affects the fitness of Cirsium hillii on previous flog posts regarding this experiment and on the background page for this experiment.

2021 Update: Dykstra’s interpopulation crosses

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:

Amy D with Miyauna and Emma after a successful day of searching for Echinacea
The first flowering plant in Amy Dykstra’s crossing experiment!
  • Start year: 2008
  • Location: Hegg Lake WMA
  • Overlaps with: Dykstra’s local adaptation
  • 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.

2021 Update: Dykstra’s local adaptation experiment

This experiment was designed to quantify how well Echinacea angustifolia populations are adapted to their local environments. In 2008, Amy Dykstra collected achenes from Echinacea populations in western South Dakota, central South Dakota, and Minnesota and then sowed seeds from all three sources into experimental plots near each collection site. Each year, Team Echinacea takes a demographic census at the western South Dakota and Minnesota plots; we abandoned the central South Dakota plot after it was inadvertently sprayed in 2009, killing all the Echinacea.

In 2021, during the annual census of the experimental plots, we found 134 living Echinacea plants, including 121 basal plants and 13 flowering plants. Only one of the flowering plants was in the Minnesota plot; the other 12 were in the South Dakota plot. For more details and graphs, please read this brief report:

  • Start year: 2008
  • Location: Grand River National Grassland (Western South Dakota), Samuel H. Ordway Prairie (Central South Dakota), Staffanson Prairie Preserve (West Central Minnesota), and Hegg Lake WMA (West Central Minnesota).
  • Overlaps with: Dykstra’s interpopulation crosses
  • Data collected: Plant fitness measurements (plant status, number of rosettes, number of leaves, and length of longest leaf)
  • Samples collected: Heads from all flowering plants
  • 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 local adaptation experiment and see a map of the seed source sites on the background page for this experiment.