So far this year, we have sadly not been able to have volunteers in the lab due to the continuing threat of COVID-19. However, over the last few months, we made quite a bit of progress on the remnant Echinacea harvests from 2020 and 2021. In the fall, we had help from volunteers, students from Lake Forest College, and externs from Carleton College. Thanks for your help! In January, Sophia finished cleaning the last head from 2021, which was an exciting accomplishment.
To track our progress in the lab, I created an R script to visualize the various steps of the ACE process for each batch of Echinacea. The figures for rem2020 and rem2021 are included here. Hopefully, this method will work for the cg harvests as well.
Click on the figures to enlarge
The ACE stages are listed along the x-axis, and the number of Echinacea heads are on the y-axis. The light blue shows how much we have completed, and the dark blue shows what remains to be done. The small numbers on each bar indicate the corresponding number of heads, and the width of the bars is roughly proportional to the amount of time each step takes. Along the top, the dates indicate the last day that the totals for each stage were updated.
The script to create these graphs can be found here: echinaceasandbox/oop/trackAceProgressTest.R
As part of the Echinacea Project’s long-term efforts to monitor reproductive fitness in the remnant populations, Team Echinacea harvested 383 seeds heads from 29 remnants during summer 2021. We randomly selected 15 heads from each population to harvest. If a population had less than 15 flowering plants, we harvested a randomly selected head from all flowering plants. In the fragmented populations we study, flowering plants often fail to produce viable seed due to limited mating opportunities. By harvesting seed heads and quantifying seed set, we can better understand how the spatial location and flowering phenology of Echinacea contribute to reproductive fitness. We are keenly interested in understanding how fire influences reproductive outcomes in fragmented prairies. To this end, we harvested seed heads from 8 populations experimentally burned during spring 2021. We will examine how fire influences mating opportunities and seed set across different populations ranging in size.
These heads we harvested are currently in the CBG lab being cleaned by volunteers and interns. We have even started scanning and counting achenes! Soon the new x-ray will be up and running, and we will begin to answer the burning questions we have about Echinacea reproduction in fragmented prairie remnants.
Stuart and Mia playing a game “harvest now?” to get independent assessments of whether Echinacea heads are ready to harvest
Start year: 1996
Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN
Data/Materials collected: 383 seed heads were collected; these are currently at the Chicago Botanic Garden. Data sheets and other materials can be found here: ~Dropbox/remData
Products: We will compile seed set data from 2021 into a dataset with seed set data from previous years.
You can read more about reproductive fitness in remnants, as well as links to previous flog entries mentioning the experiment, on the background page for this experiment.
After wrapping up our first remnant burn of the season at east riley, the crew ventured into the wild western prairies of Grant County. Earlier in the day, Mia mowed burn breaks at yellow orchid hill east. This roadside patch had considerably more fuel than east riley and NW winds remained stiff when we arrived. Once water buckets had been staged and the crew briefed, we ignited a test fire in the southeast corner. This fire backed beautifully against the wind, moving steadily and burning fuel completely. One of my takeaways from burns this spring is that prescribed burns in a little lower relative humidity (RH = 25-30) and a little higher winds (12-18 mph sustained) seem to produce great results in burn units where brome is the primary fuel.
A nice sequence of photos illustrating how the burn at yoh.e progressed. We started with a test fire and observed that small fire before proceeding to burn the entire unit. We decided to ignite the downwind edge of the burn unit and allow that fire to back against the stiff wind. Looking at the fourth and fifth photos, you can see the wind push smoke to the south as the fire backs slowly against the wind moving north.
We decided to let the fire back against the wind across the entire burn unit. Once sufficient black had been established in the southeast corner of the unit, we ignited a backing fire along the entire southern edge of the unit along Wennersborg Rd. After fire lines were secured, Gretel grabbed the push power and finished mowing burn breaks at yellow orchid hill west while Jared, Stuart, and Mia extinguished any remaining hotspots. 30 minutes after ignition, we were left with an almost entirely blackened burn unit. Beautiful, predictable prescribed burn!
Temperature – 53 F Relative humidity – 30% Wind speed (max gusts) – 18 (21) mph wind direction – NNW Ignition time – 3:44 PM End time – 4:14 PM Burn crew: Jared, Stuart, Gretel, Mia
Before and after photos looking east along Wennersborg Rd
Before and after photos looking west along Wennersborg Rd
After 5 months of preparation, we officially applied the first experimental treatments for our NSF proposal to study prescribed fire effects on prairie plant reproduction and population dynamics.
Weather conditions Tuesday afternoon were favorable for burning but wind forecasts were at the upper end of our burn prescription. Given our success burning p8 in similar conditions just a week earlier, we decided to proceed cautiously by starting with a prescribed burn on the north side of east riley. Here light and discontinuous fuel (mostly brome), a gravel road for a firebreak on the south side, and agricultural fields downwind mitigated our concerns about gusty winds. Earlier in the day, Mia mowed fire breaks along the east and west end of the burn unit. We ate lunch, loaded up our equipment, and drove down to east riley. Along the way, the crew got a great look at a western kingbird perched along Sandy Hill Road.
Once at the site, we reviewed the burn plan and staged equipment. We ignited a test fire in the southeast corner of the burn unit. Despite a slow start to the test fire and stiff NW winds that kept extinguishing the drip torch, the backing fire burned well through brome and scattered warm season grasses. With scattered poison ivy in the eastern third of east riley, we were cautious to stay upwind of smoke by lighting small strips perpendicular to the wind. Once sufficient black (burned area downwind) had been established, we proceeded to ignite the southern edge of the unit along Mellow Ln and wrap around the western end of the unit to ignite a head fire along the northern edge of the burn unit.
While somewhat patchy, we considered the burn a success. The fire behaved predictably and we felt comfortable that we could continue burning other units with more fuel. After the burn, Stuart shared the observation that the fire did not carry well in areas where fuel was covered by a film of silt/gravel. We packed up and drove a short distance into Grant County for our next set of burn units…
Temperature – 52 F Relative humidity – 34% Wind speed (max gusts) – 13 (22) mph wind direction – NNW Ignition time – 2:22 PM End time – 2:58 PM Burn crew: Jared, Stuart, Gretel, Mia
Before and after comparison looking west along Mellow Ln.
Monitoring reproductive fitness in the remnant populations is a staple Team Echinacea summer activity. 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 the summer of 2020, we harvested 304 seeds heads from 29 populations (AAN, AAS, ALF-E, ALF-W, BTG, DOG, EELR, ERI, ETH, GC, LCE, LCW, NESS, NNWLF, NRRX, NWLF, ON27, RIN, RIS, RRX, SAP, SGC, TH, TOWER, WAA, YOH). These are the same populations where we measured flowering phenology. We randomly selected 15 heads from each population, if a population did not have 15 heads, we harvested all of the heads. We harvested heads from the following populations.
These heads are currently in the CBG lab and soon we will start the process of removing the achenes and assessing seed set. We are unsure how exactly we will assess seed set because the x-ray at the Chicago Botanic Garden isn’t working now. We may weigh the seeds.
Mia Stevens heading out to harvest
A harvested head
In the spring, we plan on burning some of these remnants and also collecting heads next fall. Estimates of seed set from these heads will serve as a baseline for comparing seed set before and after a burn. We will learn how fire affects reproductive success in small prairie remnants.
Start year: 1996
Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN
Data/Materials collected: 304 seed heads were collected, these are currently at The Chicago Botanic Garden along with the paper data sheets. These data sheets need to be scanned, double-entered, and checked.
Products: We will compile seed set data from 2020 into a dataset with seed set data from previous years.
You can read more about reproductive fitness in remnants, as well as links to previous flog entries mentioning the experiment, on the background page for this experiment.
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.
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
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.
Successful pollination leads to full achenes and higher fitness later in the season!
This summer we counted shriveled and non-shriveled rows of styles three times per week for every Echinacea head in 8 of the 28 remnant populations. We also harvested 121 Echinacea heads to be analyzed for seedset data. This year we selected heads for harvest based on their position within randomly selected plots where Tracie Hayes and Lea Richardson collected vegetation data. In every randomly selected vegetation plot, all species were identified and we recorded their abundance. We marked any Echinacea head within a vegetation plot for harvest. Harvested heads are ready to be processed by citizen scientists at the Chicago Botanic Garden. In the lab, heads will be cleaned so that all achenes can be counted and x-rayed to determine seedset.
Measuring the reproductive success of an Echinacea angustifolia head gives insight into the fitness of the individual. In remnant populations, we measure reproductive success using two methods: style persistence and seedset. Seedset is the proportion of all seeds that are viable in an Echinacea head, and is measured in the lab after heads have been harvested. Style persistence is a fitness measure that can be taken during the field season. Styles, the showy female reproductive structures that emerge from every floret in an Echinacea head, shrivel within 24 hours if they receive compatible pollen. Keeping track of how many styles shrivel and how many persist can give us a sense of the reproductive success of that head without any lab work.
Year: 1996
Location: Roadsides, railroads and rights of way, and nature preserves in and near Solem Township, Minnesota.
One of many visits to each flowering plant in prairie remnants.
Assessing fitness is a key part of understanding change in any population. The Echinacea Project has focused on two quantifiable components of reproductive fitness of Echinacea angustifolia: style persistence and seed set. Styles shrivel when they receive compatible pollen, and thus persistence of styles reflects pollen limitation. A floret sets a seeds only when it has been successfully pollinated. Together, these two indicators can be used to predict how effectively individual plants produce viable offspring, giving insights into the persistence of remnant populations.
This year, we counted shriveled and non-shriveled rows of styles on each flowering head of every plant in 28 remnants three times per week. Well after the flowering season, we harvested 104 heads at a subset of these sites. The harvested heads will have their achenes removed, counted, and x-rayed by citizen science volunteers to estimate how many seeds they produced. There were several concurrent projects this summer and in the lab that use these measures, including Amy Waananen’s compatibility study and James Eckhardt’s study of edge effects.
Year: 1996
Location: Roadsides, railroads and rights of way, and nature preserves in and near Solem Township, Minnesota.
So it begins! Two new externs have joined Team Echinacea from Carleton College. We (Mikaela and Emma) will be here every day for the next three weeks, and are excited to discover new revelations for the Asynchrony, Isolation and Incompatibility experiment.
So far, most of what we’ve discovered is that cleaning Echinacea seed heads is tedious. Two days in, we have cleaned 36 seed heads; scanning them was a nice relief from the monotony. We think we could get through all 110 by the end of this week.
Although yesterday was quiet, there was a little bit of commotion: Mikaela’s second seed head had a rare deformity. Many of the achenes were uninformative. This means they were aborted part of the way through formation, so it cannot be determined whether they were fertilized. After minutes of puzzled deliberation, Stuart, Amy and Scott decided to keep them in the sample.
Four uninformative achenes compared to one normal, small-to-mid-size achene. Because of their immaturity, the florets are still firmly attached.
In contrast to yesterday, today there were quite a few volunteers and a couple of students who we got to meet. It was nice to talk to other people who were involved in and excited about this project. We also got to hear about other experiments going on in the lab besides our own.
Today’s seed cleaning also presented an exciting moment: just moments after Amy told us about last year’s larval discoveries, we each found a live larva residing in the heads we were cleaning. We’re thinking about raising these mystery larva so we can finally learn just what they are. Hopefully we’ll have more success than last year’s effort!
Our two larva. Emma’s is the tiny brown one on the right, and Mikaela’s is the pink one hanging out on a makeshift habitat of chaff.
We are grateful for this opportunity to contribute to and learn from the project, and are looking forward to the next three weeks!
