Establishing seed addition transects

As part of the 2020 NSF grant to study fire effects on plant reproduction and population dynamics, we are implementing a seed addition experiment in numerous remnants. From previous studies, we know that fire can improve recruitment which is important for population growth. However, our previous observations of recruitment in remnants conflate the amount of seed entering the seed bank and the seedlings emerging from the seed bank. The goal of this seed addition experiment is to help us directly quantify the effects of fire on seedling emergence and early seedling fitness. We will use these data to parameterize demographic models for Echinacea.

For the seed addition experiment, we established 76 transects distributed across 32 prairie remnants with Echinacea. Transect locations were determined by generating an ordered list of random points (random integers corresponding with MN state plane coordinate system) within each remnant and selecting the first 2-4 random points that were located within ~5m of an adult Echinacea but avoided dense patches of flowering plants where we may have difficulty distinguishing experimental seedlings from natural recruits. Each transect originating at a random point is 4-m long and contains four 1-m segments. Most transects extend North from the random point but some extend East (in sites where North-South transects may span an entire ditch). One segment per transect was chosen at random to be planted in fall 2021 and one transect chosen at random to be planted during fall 2022. The study includes 9 sites burned during spring 2021 as well as 7 sites slated to burn during spring 2022.

Over the past week, I have been using a GPS unit to stake the transect locations. I marked the start and end point of each transect using a blue pin flag and installed nails at 1-m intervals using measuring tape (this will facilitate the use of meter sticks and/or measuring tapes in the field). We used 4 inch galvanized common nails. Pro tip: these nails were considerably less expensive at Fleet Farm than other vendors. I plan to finish setting up transects either this afternoon or tomorrow afternoon. Our goal is to begin sowing seeds later this week.

Days growing shorter and colder

After a balmy stretch of weather (at least balmy for Minnesota in October), colder temperatures and shorter days have descended upon western MN. We experienced a killing frost Saturday (Oct 16) morning. Dwight and Jean reported that their tomatoes and other frost-sensitive garden plants are done for the year. I also awoke to frost this morning after a cold and rainy Wednesday (Oct 20).

During two of the next three nights, overnight lows are predicted to dip below 30 F. The forecast is also calling for a chance of snow (mixed with rain) Sunday morning. We had hoped for a dry, sunny stretch of weather this fall favorable for burning but the next week looks iffy.

Seed Addition Experiment: Achene Selection Process

For the seed addition experiment, we used achenes from p2 in 2016, which were selected for the batch’s particularly high seed set. The achenes were originally in 160 envelopes sorted by flowering head so that we knew which maternal plants were contributing to the experiment. The envelopes were selected mostly randomly, though some that appeared upon visual inspection to have non-viable achenes were excluded to ensure maximum viability in the achenes used for the experiment.

We combined the achenes from all 160 envelopes into one pile in order to make a homogenized mixture. Using a column blower set to 5/8″, we segregated the “rich” achenes (containing a seed) from the “thin” achenes (seedless). Achenes were considered rich if their mass was above 2 mg. We measured a sample of achenes from the final rich batch to ensure exclusion of thin achenes, finding that only about 1/30 achenes was <2 mg, and acceptable margin of error.

This collection of isolated rich achenes would became our source of seeds for the seed addition experiment. In order to divide achenes equally for use along different transects, we counted by hand achenes from the rich pile and placed them into envelopes, with each envelope containing 50 achenes. During this process, we removed achenes that appeared to be visually severely damaged to ensure that only viable achenes will be used for the experiment.

The end result of the achene selection process was 250 envelopes each containing 50 achenes, all of which were taken from a homogenized mixture of achenes whose maternal plants flowered in p2 in 2016.

Cupcakes and cleaning

On Monday, we welcomed back our second volunteer of the season, Marty. Marty is an expert on the scanner and x-ray, but since the new x-ray machine hasn’t arrived yet, she and Allen have been our rockstar head cleaners. So far, it has taken 22 person hours to clean 85 echinacea heads.  Based on these numbers, it will take an additional 56 hours to finish cleaning the 216 remaining heads in the 2020 burn rem batch that we’re currently working on.  If the volunteers continue to work at this rate, cleaning this batch would be completed by next Tuesday, October 26. In preparation for future head cleaning, we emptied out the seed dryer and refilled it with gbags from the 2021 harvest.

To celebrate several birthdays this month, Mia baked cupcakes for us! They were very chocolatey and delicious. We even made some new friends in the Plant Conservation Science Building by offering them cupcakes.

The Echinacea Project heads south

Last week, we wrapped up the last of the fieldwork in Minnesota, although four Liatris plants are taking their sweet time and weren’t ready to harvest on Friday. The remaining members of Team Echinacea packed their bags and headed to the Chicago Botanic Garden, with the exception of Jared, who is staying to monitor the stubborn Liatris. Previously, I had never been to the Garden before, so it’s been a fun place to explore. I’ve also enjoyed the elaborate Halloween decorations in the neighborhood.

This week at the Botanic Garden, we welcomed back Allen, our first volunteer since the beginning of the pandemic. It will be terrific to have some experienced volunteers to process the backlog of echinacea heads from the past several years.

At the lab, we’re also preparing for the seed addition experiment. Today, Wyatt trained us on the seed blower, a contraption that separates light achenes from heavy ones. The heavy (rich) achenes should contain seeds, and we will next randomize the rich achenes for planting this fall. We need 12,800 seeds for the experiment, and after several trials with the seed blower, we estimate that we should have enough.

Summer was fun and fall will be too!

Wyatt here,

I had a blast being a part of Team Echinacea this summer. In my 14 weeks with the project, I spent my days in beautiful prairies, gained lots of sciency skills, made many friends (both people and plants) and enemies (mainly ground squirrels), and overall had a lovely experience.

This flog post is to reminisce about all the fun I had this summer and to commemorate the fact that I will be staying on the team through the fall and for the foreseeable future! Because the Chicago Botanic Garden is so close to Northwestern, I’m able to travel there by bus to work in the lab. Better yet, Stuart was able to set up the position so that I would be able to receive work study funding from the school.

Here’s to an echinacea-filled autumn!

Experimental plot ten Pedicularis planting

To experimentally test hypotheses about how much Pedicularis canadensis, a native hemiparasite, affects the demographic rates (survival, growth, and reproduction) of other species, we planted plugs of P. canadensis in the center of a circle (with a radius of 20 cm) that contains 8 species. These eight common native prairie plant species are Echinacea angustifolia, Liatris ligulistylis, Solidago speciosa, Dalea purpurea, Pediomelum argophyllum, Sporobolus heterolepis, Koeleria macrantha, and Hesperostipa spartea. For all but Echinacea, seed was collected last year from local sources. Echinacea is the focal species of other experiments and had been planted previously. Echinacea plants served as a reference point when establishing our circles and were always directly west of P.canadensis. Circles are planted in 6 rows that were randomly selected from within the existing experimental plot 10. Rows 315, 436, 443, 643, 656, and 785 were selected. Rows contain 11 circles each, starting at 1m and going to 11m, evenly distributed 1m apart.

All circles were planted on July 29th, 2021.Plants were planted as plugs. Plugs were grown by Chicago Botanic Garden production staff before being transported to Minnesota and transplanted. Pedicularis served as the treatment and had 3 factor levels (0, 1, or 2 Pedicularis plants). Treatments were randomly assigned to circles and Pedicularis were planted in the center of each circle between August 9th and 13th, 2021. Plants in the circles were measured between August 16th and 20th, 2021.Traits measured were size and reproductive status.

Start year: 2021

Location: Grant County, Minnesota; exPt 10

Overlaps with: Experimental plot management,

Experimental plot one parasite planting update

Over the last two years I designed and planted an experiment in an already established prairie restoration (exPt01) to test hypotheses about the effects of parasite inclusion in restorations. This experimental planting of hemiparasites has three factors (Comandra umbellata, Pedicularis canadensis, and soil plugs), each with two levels (presence or absence), but three factor-level combinations are impossible because the presence of parasites is confounded with presence of soil. This translates to me having 216 row x position combinations in which I randomly assigned Comandra umbellata, Pedicularis canadensis, and soil plugs. However, roots trap soil and therefore soil is always carried in with parasites, the two treatments are confounded and so we used soil transplants to account for this.

In June, I went out and assessed the realized design of my experimental planting of hemiparasites. I assessed presence or absence of Comandra umbellata and Pedicularis canadensis at each of my 216 row x position combinations. I found only one Comandra but I found 30/72 or 42% of all Pedicularis.

In late August through early September, I planted 1 plug of Liatris ligulistylis and one plug of Solidago speciosa at each of my 216 locations.  These plants were then measured. I added these plugs to serve as response variables to my three-factored experiment.

Last year, at all 216 locations I distributed seeds from 32 native plant species. In September, I went out and assessed seedlings present. I recorded the number and photographed the seedling to identify later in the laboratory.

In late October I intend to harvest 216 strips (0.1m x 1.0m) of dried biomass (1/6th of the dried biomass) from my 216 locations as I have also done in the last 2 years.

Start year: 2019

Location: Douglas County, Minnesota; exPt 1

Overlaps with: Experimental plot management, Hesperostipa common garden experiment

Materials collected: 216 .1 x 1m strips of dried biomass are stored at the Chicago Botanic Garden.

The end of summer

As summer’s vibrant greens give way to fall’s golden glow, Team Echinacea remains hard at work in western MN. A skeleton crew is diligently wrapping up the field season. Our most important task is harvesting seed from study species so that we can quantify fire effects on plant reproduction in remnant prairies. Here is a brief update on progress for our focal species:

Echinacea angustifolia harvest: 383/383 plants harvested

Andropogon gerardii harvest: 370/370 plots measured and harvested

Liatris aspera harvest: 202/231 plants harvested

Lilium philadelphicum harvest: 79/80 plants harvested

Asclepias viridiflora: all plants harvested (~30, Jared forgot to check harvest data sheet…)

In addition to wrapping up the harvest, we are beginning to make preparations for fall burns and getting materials organized to implement a seed addition experiment designed to assess fire effects on seedling emergence and survival.

Roadkill Birthday

Hi Flog

Yesterday was my birthday, this is the second birthday that I have celebrated out here in Western Minnesota. The work day started with some sling (seedling re-finds), Alex and I did sling at Steven’s Approach and then we set off to Nessman. We quickly discovered that part of the site was mowed, and we had to go back to Hjelm to get the GPS to re-find the circles we needed to visit. We were driving away from Nessman at the corner of Dairy drive and 27 I saw something on the road. I asked Alex what it was, and she peeked out the passenger side window and said, “it’s a zucchini!” As we drove back to get the GPS, we contemplated whether we should rescue the zucchini or not. Once we saw the zucchini again, we knew we had to rescue it. After we finished at Nessman, we set of to procure our roadkill! We decided that it was most likely fell of a truck and then was run over. We scooped it up and removed the ant and millipede then buckled it into the back seat.

We then set off to Staffanson to visit two more sling circles, the two circles are on complete opposite ends of the prairie preserve. Neither circle was fairly straight forward so after we finished the last circle Alex flopped down onto the ground, I quickly joined her, and we just laid there for 10 minutes staring up at the sky taking it all in. We eventually decided that we should probably head back for lunch, and after a bit of a hike back to the car we were shocked to see the zucchini since we had forgotten all about it.

After lunch I set of two experimental plot 1 to try and sort out some issues with the measuring data. Alex and Jared worked on sorting out some demo problems. It got up to 84 degrees Fahrenheit which might be the record high for September 28th (or at least it is based on my working memory).

For dinner Jared made spring rolls, he even had ripe avocados! Spring rolls have been a staple/highlight of the summer meals. After a yummy dinner Alex and I set out to turn our roadkill into cake. We quickly determined that the zucchini was in fact not zucchini but some other sort of squash. We decided out of impatience to not peel the squash. After making the cake and very patiently waiting for it to cool, we tasted it and it was surprisingly slightly crunchy. Overall it was a wonderful day, spent in a great place, with good friends, and good food.

Moral of the story: Always peel the roadkill