Echinacea angustifolia, the titular study species of the Echinacea Project, is the only species of purple coneflower native to Minnesota. But these days, it’s not alone. Multiple other species of Echinacea, including Echinacea pallida, have been introduced to Minnesota, whether as ornamental plants in horticultural settings or as E. angustifolia substitutes in prairie restorations (pallida seed is significantly cheaper than angustifolia seed). One such restoration is located within Hegg Lake Wildlife Management Area, a key study site for the Echinacea Project.
These two species of Echinacea are visibly different, with E. pallida typically having taller flowering heads and longer, skinnier rays than E. angustifolia. E. pallida also has white pollen, while E. angustifolia has yellow pollen. E. angustifolia is found throughout the western half of Minnesota, while E. pallida is native to Iowa, Illinois, and other more southern states. But why does this matter? Non-native plants like E. pallida can be aesthetically pleasing, and may even provide some of the same ecological benefits as their native counterparts. However, non-native plants can also outcompete native plants, and if hybridization occurs, may dilute locally adapted native gene pools. Experimental plots 7 and 9 (ExPt07 and ExPt09) were designed to determine if E. pallida can produce viable hybrid offspring with E. angustifolia, and to monitor the fitness of these hybrids.
One of our jobs this year was to measure all of the surviving plants in ExPt07 and ExPt09. We used different protocols for the two plots, but both went by mostly without a hitch. Compared to ExPt01, these plots had far more flowering plants: 37 flowering individuals were found in ExPt07 (29% of searched positions) and 106 were found in ExPt09 (44% of searched positions). The plants that were flowering also seemed to have, on average, more flowering heads (one plant had 18!). E. pallida generally produces more flowering heads, so seeing this pattern in its hybrid offspring made sense.
The legendary “tri-butt”Stuart, marking the boundaries of ExPt07
While we observed many healthy flowering heads, we also noticed lots of failed attempts at flowering (i.e. vertical developments), unsuccessful buds, and even “mutant” flowers (see the “tri-butt”, above). Whether this is an effect of hybridization or simply a result of the larger sample size of flower heads is unclear. If hybridization does increase the rate of unsuccessful flowering attempts, reducing fitness, it presents an immediate threat to populations of E. angustifolia within pollination distance of E. pallida restorations. Which brings us back to the restoration at Hegg Lake WMA…
After counting heads and identifying unique tag numbers for all of the flowering E. pallida plants in the Hegg Lake restoration, we took matters into our own hands. To prevent genetic swamping of nearby wild E. angustifolia, we beheaded every E. pallida plant in the restoration. Guillotined them. Total decapitation. If it sounds violent, that’s because it was. Robespierre would have been proud of us.
Say what you will about our methods, but Echinacea pallida won’t be showing it’s face at Hegg Lake WMA for a long, long time.
Reproduction in plants can be limited by access to pollen and resources. We previously found that Echinacea plants in the remnants are pollen limited, meaning that if they had access to more pollen, they would produce more seeds. However, the long-term effects of pollen limitation are unknown. Do plants that are super pollen saturated and have high amounts of pollen have a higher lifetime fitness than plants that are pollen limited? Also, we know that the plants in the remnants are pollen limited, but are the plants in the common garden environment also pollen limited? To answer these questions and more, 14 years ago Gretel randomly selected 39 plants from p1; half of these plants were randomly assigned to the pollen addition group, and the others were assigned to pollen exclusion. Every year, plants in the pollen exclusion have their heads bagged and they are not pollinated, while we hand cross every style in the pollen addition group.
In the summer of 2026, NONE of the original 39 addition/exclusion plants were flowering. If any had been flowering, the exclusion treatment plants would be covered with exclusion bags to prevent pollination, and the addition plants would be hand-pollinated multiple times throughout the summer. Of the 25 plants that were identified as alive last year, 24 were successfully found again this year.
Our 2026 field season kicked off on Monday, June 29th! Stuart, Aaron, Maria, Yavonne, and I (Max) met at the Hjelm house in the morning for a brief but comprehensive introduction to the project before heading out in Stuart’s truck to see some of the study sites.
We started at Staffanson Prairie, where Stuart gave us the lay of the land and introduced us to some prairie plants while a swarm of ravenous mosquitos introduced us to some prairie insects. Then an unexpected storm cloud rolled through to introduce us to some prairie weather and we hopped back into Stuart’s truck. The rest of the tour was given through the truck windows, except for a brief stop at Hegg Lake (where I promptly lost my sunglasses).
Stuart, Aaron, Yavonne, and Maria at StaffansonA bee hiding out from the sudden downpour under an Echinacea head
Tuesday was our introduction to experimental plot #1 (exPt01). After a quick demonstration of Visor data entry, we were set free to measure inbreeding experiment 1 (INB1). We would be recording plant status (Basal/Flowering/Can’t Find), counting basal and flowering rosettes, and counting basal leaves. For flowering plants, we would also be twist-tying and recording flowering head information. This task was daunting at first, but we quickly figured out how to identify individual rosettes and sort through a thick layer of duff to count leaves. It helped that we had Aaron, who had already worked with the Echinacea Project for a full summer last year, to answer our questions.
By the end of the day on Thursday, we had finished our measurements in INB1 and INB2. Between the two experiments, we searched 381 positions for plants. We were unable to find 66 plants (we’ll return to these later in the summer to search again), and recorded 310 plants. These numbers are roughly on par with what was expected, given last year’s plant count (329) and a year’s worth of mortality. What surprised us was the frequency of flowering plants: while last year’s team found 92 flowering plants between the two experiments, we encountered only four!
Why this discrepancy? It probably has to do with fire. ExPt01 was burned last year, and we know from the past three decades of research that fire enhances Echinacea angustifolia flower and seed production. Maybe the Echinacea plants in INB1 and INB2 are still rebounding from last year’s flowering event? Maybe the somewhat cool start to the summer delayed flowering phenology? Maybe we made an outrageous counting mistake and missed 80+ flowering plants? All of these explanations are plausible. Only time and future flog posts will reveal the truth. Stay tuned!
For the past several years we have been investigating effects of prescribed fire on native ground-nesting bees in remnant prairies and restorations across our fragmented prairie landscape. We have a paper about effects of fire on the abundance and diversity of nesting bees in prep for a peer-reviewed journal. We are posting recommendations from this investigation now as a one-page non-technical document.
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR) and by the National Science Foundation.
For the past few years we have been studying effects of prescribed fire on pollination, pollinators, and plants across our fragmented prairie landscape. We have a paper about effects of fire on pollen that we are preparing to submit to a peer-reviewed journal. We are posting recommendations from this investigation now as a one-page non-technical document.
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR) and by the National Science Foundation.
For the past few years we have been studying effects of prescribed fire on pollination, pollinators, and plants across our fragmented prairie landscape. We have three papers we are preparing for submission to peer-reviewed journals. From each, we have recommendations for land managers interested in conserving native prairie bees and plants. We are posting these recommendations now in a one-page non-technical format.
The first paper is about prescribed fire effects on pollination and pollinator visitation. Read the recommendations that are based on the paper.
Expect two more one-pagers tomorrow.
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR) and by the National Science Foundation.
Last week I trekked out to Landfill to see if I could acquire some aphids and I was successful! The most successful way of harvesting them in the past which was using a paintbrush that had a small amount of bristles. However, I found most successful for preparing the Aphids to move is slightly blowing on them. This provoked them enough to retract their styles so I could sweep them using a larger paintbrush. After a drive back, I put them back onto the leaves of the addition plants in ExPt01.
This week I was met with some pretty unfortunate news after visiting the addition plants in ExPt01, they were no longer present. So to remedy this, I will venture back out to landfill and harvest more aphids and check back in with them tomorrow afternoon to make sure that they are thriving on their respective plants.
The Echinacea Project, and its principal investigator Stuart Wagenius, is responsible for the foundation of one of the most comprehensive and long-running studies of prairie plants. Experimental plots use a common garden design and include experiments involving inbreeding, aphid addition and exclusion, flowering phenology, pollen addition and exclusion, and more. The Echinacea angustifolia in experimental plot 1 were planted as far back as 1996; while they have experienced mortality over the years, many of these plants are still alive. Team Echinacea, most of which are younger than the plants we work with, have been hard at work collecting measurements to add to the ever-expanding dataset. We take data on things like the number of rosettes, leaves, and flowering heads a plant has, as well as insect activity and disease spread, to help determine the fitness of the plants in various treatments.
A common wood-nymph being thwarted by our pollinator-exclusion bagsAn Agapostemon virescens visiting echinacea in ExPt01A fungus commonly found growing in ExPt01A jumping spider on the hunt, likely preying on floral visitorsDragonflies, abundant in ExPt08Aaron, having a standoff with a grasshopper
As of August 1, 2025, we have measured approximately 60% of experimental plot 1, which has over 11,000 planted positions. Having accomplished so much, we plan on beginning harvesting soon next week. After the heads are harvested, the achenes will be sent to the Chicago Botanic garden, where interns and volunteers will work to determine the flowers’ seed set. Throughout the rest of the field season, Team Echinacea will continue measuring in ExPt01, and begin on ExPt08, ExPt09, ExPt07, and ExPt02.
This is a map of measuring progress in ExPt01, where the blue segments have been completed and the white, unfilled sections are soon to be measured. We measure by experiment, concluding one before we move to another. We have completed the inbreeding 1 cohort, the inbreeding 2 cohort, and the first generation of the heritability of fitness experiment. Currently, we are working on the 99 main garden, a series of rows planted by Stuart in 1999.
The aphid addition and exclusion experiment was started in 2011 by Katherine Muller. The original experiment included 100 plants selected from exPt01 that were each assigned to have aphids either added or excluded across multiple years. The intention is to assess the impact of the specialist herbivore Aphis Echinaceae on Echinacea fitness.
In 2025, 32 of the original 100 plants were alive, 12 addition and 20 exclusion plants. Unfortunately, no aphids were found in exP01 but many aphids were found in other remnant plots this year. As soon as I can I will transfer aphids from the plants out in remnants to plants in exP01 to get this experiment on the move.
Plant status (basal, flowering, not present), aphids present, ants present, herbivory (number of leaves significantly chewed on), and the number of aphids added/removed (depending on specific treatment)
Protocols and datasheets are located at ~Dropbox\aphidAddEx\aphids2025
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
Team Echinacea has begun the annual census of Echinacea plants. Each year we census all flowering plants at over 30 prairie sites. Each plant gets a digital census record, a flag, and a tag. Most plants already have a tag, so we don’t give them a new one. But some have lost their tag or are flowering for the first time, so they need a new tag. New tags this year are numbered starting at 30,001. Plants get neon flags and we will come back and survey them so we can make a map of the location of every plant. Once they get surveyed, we replace the neon flag. All of these efforts help build a long-term dataset about the survival and reproduction of these very long-lived plants. These plants face many challenges living in small prairie patches, but they are tough.
Below is a summary of the number of census records taken so far at nine sites
site rawSite demo.id
1 other 1
2 alf around landfill 11
3 cg common garden 23
4 eelr east elk lake road 19
5 lfe landfill east 118
6 lfw landfill west 99
7 lce loeffler corner east 78
8 lcw loeffler corner west 81
9 rrxx railroad crossing 36
