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In the summer or 2018, Lea collected data for the third year of her observational study quantifying
 Flowering Liatris flowering phenology and reproductive success (seed set) for Liatris aspera and Solidago speciosa plants located along a transect at Staffanson Prairie Preserve. Staffanson is divided into east and west units. The west unit of Staffanson was burned Spring 2016. In 2016, Lea looked for differences in phenology and reproduction of east vs. west Liatris and Solidago plants. In 2017, neither unit was burned. In 2018, the east unit burned. Data collected this year combined with data collected in 2016 and 2017 will enable us to to see if burns influence phenology or reproduction. To assess phenology, Lea visited plants three times a week and recorded if they were flowering. She took GPS data for each plant included in the study. She also mapped the seven nearest neighbors of all flowering plants within her transect in 2018. Additionally, Lea visited all plants in the 2016 and 2017 datasets to see if they were still present and if they were flowering. To assess reproduction (seed set), plants were harvested and brought back to the Chicago Botanic Garden so that seeds could be removed from the plant and x-rayed. This study helps us understand how fire, phenology, and reproduction are linked in species that are related to Echinacea angustifolia.
Start year: 2016
Location: Staffanson Prairie Preserve
Overlaps with: Fire and fitness of EA, Flowering phenology in remnants
Physical specimens:
- ~80 harvested Liatris aspera specimens from summer 2018, located at the CBG
- ~80 harvested Solidago speciosa specimens from summer 2018, located at the CBG
Data collected: Phenology data was taken on the visors every Monday, Wednesday, and Friday through the growing season. Paper harvest data sheets were used and brought back to CBG.
GPS points shot: ~543 GPS points were visited or shot, one point was visited for each plant monitored in summer 2016 and 2017, and points were shot for each plant in the 2018 dataset along with its seven nearest neighbors.
 Michael adds pollen to one of the “addition” plants using a toothpick and a vial of collected pollen. Does receiving the maximum amount of pollination vs. no pollen at all affect a plant’s longevity or likelihood of flowering in subsequent years? Since 2012, we have been either adding or excluding pollen from the same plants’ heads to test what role pollen plays in ongoing survival and flowering. Unlike the previous two years, many plants in this experiment flowered this year, and analyzing them will likely reveal interesting results.
This summer, 14 of the 26 plants remaining in the pollen addition and exclusion experiment flowered, for a total of 25 heads. This is the most heads the pollen addition and exclusion project has had since 2013. We continued experimental treatments on these flowering plants and recorded the survival and flowering status of all plants in the experiment. Of the original 38 plants in this experiment, 12 of the exclusion plants and 14 of the pollen addition plants are still alive.
In this experiment, we assess the long-term effects of pollen addition and exclusion on plant fitness. In 2012 and 2013 we identified flowering E. angustifolia plants in experimental plot 1 and randomly assigned one of two treatments to each: pollen addition or pollen exclusion. When plants flower in subsequent years they receive the same treatment they were originally assigned. The increase in flowering rates this year will allow us to move forward with analyzing this data set, to potentially answer this 7-year question.
Start year: 2012
Location: Experimental plot 1
Physical specimens: We harvested 25 flowering heads from this experiment that will be pulled from the normal ACE processing and pushed through faster. This is so we can more quickly determine achene count and proportion of full achenes.
Data collected: Plants survival and flowering data was recorded as part of our annual surveys in P1 and can be found with the rest of the P1 data. Data on when heads had pollen added can be found in CGData/115_pollenLimitation, particularly dailyPollenAddition for the year 2018.
You can find more information about the pollen addition and exclusion experiment and links to previous flog posts regarding this experiment at the background page for the experiment.
This summer Team Echinacea continued adding and excluding aphids to plants in the experiment that Katherine Muller started in 2011. Katherine Muller randomly designated a sample of 100 Echinacea plants in experimental plot 1 for either aphid addition or removal.
Andy managed the project for the team in 2018, making sure that aphids were removed from the exclusion plants, and added to the addition plants. Twice a week, Andy (and occasionally Morgan) visited every plant in the study, recording the number of aphids, ants, and leaves infested. There remain 54 plants in the aphid study, 26 from the aphid addition plants and 28 from the exclusion plants. The data for this year will be added to the ongoing dataset.
Aphis echinaceae is a specialist aphid that is found only on Echinacea angustifolia. Read more about this experiment.
That’s a lot of aphids! Start year: 2011
Location: Experimental Plot 1
Overlaps with: Phenology and fitness in P1
Data collected: All sheets describing the addition and removal of aphids from echinacea are stored in two places. All physical sheets are in Stuart’s manila folder titled “Aphid Add/Ex 2018.” Additionally, all data from the sheets are present in the aphidAdd2018Master and aphidEx2018Master. The exact path of this file may change but is currently ~\Dropbox\teamEchinacea2018\andyHoyt\aphidAddEx2018\aphidDataAllYears
Physical specimens: We harvested 25 flowering heads from this experiment that will be pulled from the normal ACE processing and pushed through faster. This is so we can more quickly determine achene counts and proportions of full achenes.
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 previous flog entries mentioning the experiment, on the background page for this experiment.
Over 90% of flowering plants rely on insect pollinators for sexual reproduction. Pollination biologists often quantify pollinator effectiveness by counting the number of pollen grains a pollinator deposits on a plant’s stigma in a single visit. However, flowers in the Asteraceae, like Echinacea, are uniovulate, meaning that a there is just one ovule per style. Therefore, it theoretically only takes one viable pollen grain to fully set seed in an Echinacea ovary, which means the standard method of quantifying pollinator effectiveness may not be appropriate for Echinacea and other members of the Asteraceae. In this study, we wanted to estimate how many pollen grains are really necessary to set a seed in Echinacea angustifolia. We performed 60 hand crosses with varying levels of pollen deposited. Each cross consisted of nine total styles of which three were removed before the cross to get estimates of self-pollen deposition, and six styles were crossed with pollen from other flowering individuals. We then collected styles and stained them using fuchsin gel and to count the number of pollen grains using a compound microscope. We x-rayed the achenes, fruits, from the crosses to determine if a seed was present. Preliminary data shows that seed set varies with the pollen grains deposited. These data will advance our understanding of pollinator effectiveness in this uniovulate plant. By increasing our understanding of pollinator efficiency in the Asteraceae we can better predict the consequences of pollinator declines in fragmented habitats, such as the North American tallgrass prairie.
 Mia doing one of her many, many crosses Start year: 2018
Location: exPt2
Overlaps with: The Big Event, Bees Remove and Deposit Pollen
Physical specimens: 183 Echinacea heads were dissected at the College of Wooster in fall 2018. They are currently being processed at CBG.
Data collected: Contact Dr. Jennifer Ison or Mia Stevens for data related to this experiment
Team members who have worked on this project include: Mia Stevens (2018) is the lead on this project.
In plant populations where reproduction is mate-limited, the potential exists for selection on floral traits through both male and female function (seed production and siring success). Selection could be strong because of high variation in both male and female fitness. Additionally, most plants rely on a number of generalist insect pollinators, each of which is likely imposing selection on plant traits associated with reproduction. In many plant species, these generalist pollinators are native solitary bees. However, pollination research mainly focuses on large social bees—bumblebees and the non-native honeybee.
The main objective of this research project is to quantify how four generalist solitary bee taxa contribute to male and female fitness in the mate-limited prairie perennial, Echinacea angustifolia. To accomplish this objective, 15 researchers worked together to monitor the complete pollinator visitation in a prairie community with over 200 flowering Echinacea individuals during five days in July 2018. Through this effort, we recorded over 700 individual bee visits to a flowering Echinacea plant. To assess seed set, we removed achenes from Echinacea seedheads produced during the five observations day and xrayed the achenes for viable embryos.
Currently, we are germinating the resulting seeds and taking leaf samples. This summer, we will extract DNA from the leaf samples and genotype each sample at 11 previously optimized Echinacea-specific microsatellite loci. We will use a full paternity maximum likelihood analysis to quantify siring success mediated by the different generalist bee taxa. Our results will advance our understanding of relationships between male, female, and total fitness in plant populations. Our results will also reveal how different pollinators may cause variation in fitness. These results can help us predict the effects of changing pollinator communities for fragmented plant populations.
 Everyone in exPt2 looking for bees Start year: 2018
Location: exPt2
Overlaps with: Bees Remove and Deposit Pollen, Pollen to Seed
Physical specimens: 183 Echinacea Heads are currently being processed at CBG
Data collected: Contact Dr. Jennifer Ison for data related to this experiment
Team members who have worked on this project include: Everyone in 2018! The big event was just that- a few very big events
In summer 2018, I harvested 80 seedheads from 12 remnant Echinacea populations (ALF, EELR, KJ, NWLF, GC, NGC, SGC, NNWLF, LC, RRX, NRRX, YOH) to study patterns of reproductive fitness. I sampled heads in two ways – (1) I randomly selected 20% of the individuals at each site (43 individuals) and (2) I randomly sampled up to 5 individuals from full factorial combinations of high, medium, and low spatial isolation and early, peak, and late flowering time (i.e., high spatial isolation/early flowering, high spatial isolation/peak flowering, etc.) across all sites (37 individuals).
In January 2019, I dissected seedheads that I collected from the NW sites (ALF, EELR, KJ, NWLF, GC, SGC, NGC, KJ, NNWLF). I extracted the achenes by row to observe temporal variation in seed set within heads. I x-rayed the achenes and assessed seed set in January.
 Xray images that show whether achenes contain embryos or not Start year: 1996
Location: Remnant prairies in central Minnesota
Overlaps with: Phenology in the Remnants, Gene Flow in Remnants
Products: Check back with the flog for preliminary results and annual reports.
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.
In summer 2018, I began a project to look at pollen movement within and among the remnant populations. To do this, I chose two focal areas, the NW sites in the study area (populations: ALF, EELR, KJ, NWLF, GC, SGC, NGC, KJ, NNWLF) and the SW sites (populations: LC, NRRX, RRX, YOH, and two large populations in between these sites). I mapped and collected leaf tissue from all individuals in the study areas and harvested seedheads from a subset of these individuals (see Reproductive Fitness in Remnants). I am currently extracting the DNA from the leaf tissue samples and a subset of the seeds I collected, and will use the microsatellite markers that Jennifer Ison developed in her dissertation to match up the genotypes of the offspring (i.e., the seeds) with their most likely father (i.e., the pollen source).
 An Echinacea that has had today’s load of pollen fully removed by pollinators Start year: 2018
Location: Remnant prairies in central Minnesota
Overlaps with: Reproductive Fitness in Remnants, Phenology in the Remnants
Products: Check back with the flog for preliminary results and annual reports.
Team members who worked on this project include: Amy Waananen
In 2018, we checked 80* focal plants at 12 remnants for nearby seedlings found in previous years. We found 97 out of the original 955 seedlings (26 fewer than the 123 found last summer). Although challenging to obtain, information about the early stages of E. angustifolia in remnants is critical to understanding the demography of these remnant populations. With still no flowering plants, it is plain to see how long it takes for Echinacea to begin flowering.
Between the summers of 2007 and 2013, team Echinacea observed the recruitment of Echinacea angustifolia seedlings around focal plants at 13 different prairie remnants. The locations of these seedlings were mapped relative to each focal plant and the seedlings (now former seedlings) are revisited each year. For each of these former seedlings, we make a record each year updating its status (e.g., basal, not found), rosette count, and leaf lengths. We also try to update the maps, which are kept on paper and passed down through the years, each person using a different color ink. As you can imagine, they are quite colorful & marked up by now.
It can be tough to find small plants like this one! Year started: 2007
Location: East Elk Lake Road, East Riley, East of Town Hall, KJ’s, Loeffler’s Corner, Landfill, Nessman, Riley, Steven’s Approach, South of Golf Course remnants and Staffanson Prairie Preserve.
Overlaps with: Demographic census in remnants
Data collected:
- Electronic records of status, leaf measurements, rosette count, and 12-cm neighbors for each seedling. Currently in Pendragon database
- Updated paper maps with status of searched-for plants and helpful landmarks
Products: Amy Dykstra used seedling survival data from 2010 and 2011 to model population growth rates as a part of her dissertation.
You can read more about the seedling establishment experiment and links to previous flog entries about the experiment on the background page for this experiment.
* This number originally read 119, which is incorrect according to the sling master datasheet from 2018. EE edited this on 8 Jan 2020 while writing the PSR for 2019. I encourage someone to correct this number if it is now incorrect but to the best of my knowledge 80 is the number of maternal plants/circles visited.
This year in experimental plot 2, we measured pollinator visitation rates, per visit pollen removal, and per visit pollen deposition across common pollinator taxa to provide insight into pollination failure in Echinacea. We collected male and female phase floret samples from 183 Echinacea head observations conducted from July 9th to the July 31st, 2018. The pollinator taxa included in analysis were Andrena (N=18), Augochlorella (N=9), male Melissodes (N=53), small black bees (N=59), and unvisited heads used as environmental controls (N=30). Using light microscopy, we then quantified the number of pollen grains in these samples to determine how much pollen an individual of each taxon removes and deposits per visit. We found that the composite specialist Andrena rudbeckiae removes more grains of pollen per visit than the other common pollinator taxa in the study area; namely, male Melissodes sp., Augochlorella sp., and ‘small black bees,’ a wide taxonomic group comprising a variety of species mostly in the Halictidae. Pollen limitation in the population could be driven by frequent male Melissodes sp. visitation late in the season; based on the per visit removal of male Melissodes sp. and number of visits observed in this study. These results combine to contribute to our understanding of pollination failure and pollen limitation in small fragmented flowering plant populations.
 Mean pollen count of male phase floret samples after visitation compared across pollinator taxa Start year: (Official Experiment) 2018
Location: Experimental plot 2 at Hegg Lake WMA
Overlaps with: ExPt2
Physical specimens: 183 Echinacea heads in egg cartons
Data collected: Contact ZZ, EJ, or JLI for access to their data
Product (to come): Zeke Zelman’s Senior Thesis at Wooster College, 2019
Team members who worked on this project include: Zeke Zelman, Evan Jackson, and Jennifer Ison (2018)
In summer 2018, we searched experimental plot 7 for Echinacea plants that are crosses between and within E. angustifolia and E. pallida. Of the 294 plants originally planted, we found 169. However, for the first time in the history of experimental plot 7, we found a flowering plant (an E. pallida x pallida cross)! The table below shows the counts of Echinacea plant in the summer of 2018. In addition to the lowest survivorship, the native E. angustifolia also has been the smallest (above-ground) over the five experimental years. Uh oh!
Riley with the first ever flowering head in exPt7!
| Status 2018 |
ang x ang |
ang x pal |
pal x ang |
pal x pal |
| not found |
52 |
12 |
26 |
35 |
| found |
22 |
16 |
59 |
72 |
Start year: Crossing in 2012, Planting in 2013
Location: Hegg Lake Wildlife Management Area – Experimental Plot 7
Overlaps with: Echinacea hybrids: exPt6; Echinacea hybrids: exPt9
Data collected: Rosette number, leaf number, length of longest leaf, herbivory for each plant collected electronically and exported to CGData. Recheck information for plants not found was also collected electronically and stored in CGData. In 2018, Riley also used a Li-Cor 6400 to analyze ecophysiological traits of Echinacea in expt7. This included photosynthetic rate and water use efficiency. Riley has this data and we’ll make it available after he’s done with his thesis.
Products: Riley’s 2018-19 Biology Honors Project at Gustavus. Riley found that within-species Echinacea angustifolia crosses have lower survivorship, above-ground biomass, and ecophysiological traits than other cross types. Riley made a poster, is writing his thesis, and will defend it in May.
You can read more about rexPt7, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.
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