A cold, wet spring put an early damper on our 2022 burn season but we got a great start this week with an efficient two-day trip to Minnesota. The weather looked sufficiently warm and dry to justify the trip from CBG. Our goal was to prep burn units in anticipation of better burn weather. Stuart and I thought there was an outside chance we might be able to burn P1 or the Andropogon pilot plot on Friday but conditions were far better than anticipated. Fuels were dry and steady south winds brought drier air. We focused our efforts Thursday on preparing burn units. Alex and I mowed/raked breaks at waa and mapp in the morning. Stuart joined us after lunch to scout lcw, mark the burn unit boundary at lfw, and remove a handful of pine and cedar trees within the unit. Alex and I finished the day by mowing breaks at nwlf and cutting breaks at sgc.
Pasqueflowers, prairie skies, and fresh ash at Staffanson Prairie.
The weather conditions that materialized Friday were ideal for prescribed burns: steady southeast wind, high temperatures in the mid 60s, relative humidity dipping to 30-35 percent, and good smoke dispersal. We were able to burn six experimental units and one bonus prairie garden between 11 AM and 6 PM. The Echinacea Project was not alone. TNC burned the western half of Staffanson on Friday and USFWS burned several WPAs. It was a very successful and efficient trip. Stay tuned to the flog for more detailed information about each experimental burn.
Burning Jean’s prairie garden at the end of the day. Thanks to Alex C. for the photos.
This summer we harvested seed pods from 25 Green Milkweed (Asclepias viridiflora) plants in the study area. Green Milkweed is uncommon and seems to be declining in our study area. This species prefers similar habitat to Echinacea. Plants tend to be sporadically distributed across dry prairies on steep hillsides, sandy soils, and well-drained gravelly areas. Our experience has been that flowering plants often fail to produce seed. We rarely find more than a handful of plants that produce pods in a given year.
Flowering Green Milkweed with bumblebee visitor at Staffanson.
Green Milkweed with three pods at Landfill East.
After harvesting and drying seeds, Jared cleaned seed by removing their fluffy coma. Jared then counted all the seeds and randomly selected a minimum of 30 seeds for x-raying. X-rays revealed variation. Some ovules lacked an embryo , others had whole, intact embryos. Many ovlues fell somewhere in between. They contained embryos that were undersized, shriveled, or fragmented. There was no external evidence of seed predation. The proportion of full ovules ranged from 0 to 100 percent. We are not sure whether “partials” reflect resource limitation and seed abortion, a form of late-acting self-incompatibility, or something else entirely. We are doing some research to help us interpret the biology underlying these patterns.
X-ray image of Green Milkweed seeds. Note the variation in embryo size, shape, and integrity in the x-ray image.
Scanned image of the same Green Milkweed seeds.
After cleaning, counting, and classifying, Jared prepared a subset of Green Milkweed seed for germination. CBG’s production greenhouse will germinate and grow 392 milkweed seedlings representing 15 maternal lines. We will plant these seedlings in an area south of P8. Although these plants grow slowly, our hope is that they will be an excellent resource for investigating milkweed pollination in a couple years. We also hope to harvest seed from these plants and include Green Milkweed in our seed mixes for restoration!
In summer 2020, Team Echinacea established two plots south of experimental plot 8 for a pilot experiment examining fire effects on Big bluestem (Andropogon gerardii) reproduction. Neither plot was burned during 2020. During spring 2021, we randomly selected the western plot to be burned.
Within each rectangular plot, we selected 30 random points. We then counted the number of flowering Andropogon culms within circular 1m2 subplot centered on each random point (within 56.4 cm). After excluding random points that overlapped with the plot boundary or other random points, we were left with 24 usable random points in the eastern plot and 23 usable random points in the western plot.
Stakefile for random plot locations: ~Dropbox/geospatialDataBackup2021/stakeFiles2021/stakeAndroPilot2021.csv
Scanned data sheets: ~Dropbox/burnRems/pilotAndro/androPilot2021
Samples or specimens collected: Seed heads collected from 2020 and 2021 are currently stored in Jared’s office. These have been dried and will be cleaned / x-rayed to quantify seed set.
Products: Stay tuned!
You can read more about the Andropogon fire and flowering in exPt08 experiment, as well as links to prior flog entries about this experiment, on the background page for this experiment.
In 2021, Team Echinacea established 76 transects (each 4 m long) across 32 patches of remnant prairie in the study area. 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.
Map of 76 transects
Start year: 2021
Location: 32 patches of remnant prairie in and around Solem Township, MN
Data collected: locations for seed addition transects: ~echinaceagis/remSeedAdditionExpt/remSeedExptTransectLocations.csv
Samples or specimens collected: NA
Products: Stay tuned!
You can read more about the seed addition transects in remnants, as well as links to prior flog entries about this experiment, on the background page for this experiment.
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. 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. Seeds were sowed in groups of 50 (either one or two packets of 50 per segment planted). All seeds were derived from the 2016 heads harvested in p2.
Foggy transect at the hulz hills
Start year: 2021
Location: 32 patches of remnant prairie in and around Solem Township, MN
Data collected: All data related to planting can be found here: ~Dropbox/burnRems/seedExp
Samples or specimens collected: Seed packets to be planted in fall 2022 are stored in see-through glass cabinets in the population biology lab at CBG.
Products: Stay tuned!
You can read more about the fire and seedling fitness in remnants experiment, as well as links to prior flog entries about this experiment, on the background page for this experiment.
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.
In 2021, Team Echinacea established 378 random points across 27 prairie remnants in western Minnesota. After delineating the boundaries of remnant prairie patches of interest, we established between 6 and 24 random points within each patch (number of points roughly proportional to patch area). These points serve as sampling locations to help Team Echinacea characterize fire effects on the reproduction of plant species like Hesperostipa spartea and Andropogon gerardii. These points may also serve as infrastructure for future research projects.
Map of 378 random point locations.
Start year: 2021
Location: Roadsides, railroad rights of way, and nature preserves in and around Solem Township, MN
Data collected: stakefile with 378 random point locations can be found: ~Dropbox/geospatialDataBackup2021/stakeFiles2021/randomPointsInRems/stakeRandomPointsInRems2021.csv
Samples or specimens collected: NA
Products: NA
You can read more about Random points in remnants, as well as links to prior flog entries about this experiment, on the background page for this experiment.
In summer 2021, Team Echinacea searched for and mapped 71 Green Milkweed (Asclepias viridiflora) plants across 8 patches of remnant prairie in our study area in western MN. This denizen of dry prairies is tough to spot and appears to be declining across its range. Our goal is to monitor Green Milkweed individuals in the study area to better understand their demography, responses to prescribed fire, and reproduction. We located and mapped 70 Green Milkweed plants, 59 of which flowered. Of the plants that flowered, 31 produced pods. We harvested pods from 22 plants for further study in the lab and (hopefully) growing some plants from seed.
Flowering Green Milkweed at Staffanson with a pod! Note the patent-pending rubberband technique that we used to prevent pods from releasing seeds before harvest.
Start year: 2021
Location: Remnant patches of prairie in and around Solem Township, MN
Overlaps with: NA
Data collected: demographic data: ~Dropbox/burnRems/remAv/data2021/ascvir2021.csv
Samples or specimens collected: Pods/seed collected during summer 2021 currently reside in Jared’s office. These seeds need to be inventoried, cleaned, counted, and x-rayed.
Products: Stay tuned!
You can read more about the Asclepias viridiflora demography project, as well as links to prior flog entries about this experiment, on the background page for this experiment.
During late summer 2021, we began collecting data in remnant patches of prairie to quantify fire effects on the reproduction of Porcupine grass (Hesperostipa spartea). We visited 209 random points established during the summer across 17 remnant patches and counted the number of flowering Hesperostipa culms rooted within 1 m of the random point. Across the 209 plots, we counted 1159 culms. The highest density we observed was 101 culms in one plot at Landfill East. In addition to counting culms, we also counted the number of fruits produced by culms in each plot. The plot with 101 culms at Landfill East also held the record for fruit count at 523!
Mia collecting data on Hesperostipa reproduction in remnants.
Start year: 2021
Location: Remnant patches of prairie in and around Solem Township, MN
Data collected: ~Dropbox/burnRems/remStipa/data2021/remStipa2021Data.csv
Samples or specimens collected: Seeds collected and counted during June 2021 were broadcast in exPt08
Products: Stay tuned!
You can read more about the Hesperostipa fire and flowering in remnants experiment, as well as links to prior flog entries about this experiment, on the background page for this experiment.
During late summer 2021, we began collecting data in remnant patches of prairie to quantify fire effects on the reproduction of Big bluestem (Andropogon gerardii). We visited 376 random points established during the summer across 27 remnant patches and counted the number of flowering Andropogon culms rooted within 1 m of the random point. Across the 376 plots, we counted 1450 culms. The highest density we observed was 163 culms in one plot at KJs. We also collected seed heads from all culms within 1 m of the random points to x-ray and quantify seed set.
Jared searching in vain for Andropogon culms at Staffanson.
Start year: 2021
Location: Patches of remnant prairie in and around Solem Township, MN
Data collected: ~Dropbox/burnRems/remAndro/fieldData2021/remAndro2021DataVerified.csv
Samples or specimens collected: Seed heads collected during summer 2021 have been dried and currently reside in Jared’s office. These samples will be cleaned, processed, and x-rayed to quantify seed set.
Products: Stay tuned!
You can read more about the Andropogon fire and flowering in remnants experiment, as well as links to prior flog entries about this experiment, on the background page for this experiment.
