new radiographs of Echinacea fruits

For our seed addition experiment, we want to know exactly how many seeds we planted in each 1 m transect. Each transect got seeds from one envelope. Before planting, we took xrays of the fruits in the paper envelopes. With minimal processing, the radiographs look good! We have a batch of 251 images to classify. This sounds like a job for Allen Wagner aka “the Count” (of Achene County).

We used the column blower and other techniques to remove empty fruits. We aimed for about 50 seeds per envelope. How many do you count?

space weather

Good grief! As if regular old atmospheric inclement weather wasn’t enough to worry about, now we can worry about inclement ionospheric weather too! The fire season appears to be coming early and strong, which may make it difficult to conduct prescribed burns and work outdoors. The upcoming solar maximum appears to be coming early and strong, which makes it difficult to use our precision GPS machines, which are essential to our fieldwork.

Here’s a MnDOT bulletin from today warning us to expect bad performance of gps due to space weather rocking the satellites.

Read more about the the Solar Cycle 25 peak:

red flag

Red flag warning for our study area and much of Minnesota. What does this portend for the prescribed burning season?

florets and the Fibonacci series

In the lab today we were talking about Fibonacci numbers. Somehow these numbers (1, 1, 2, 3, 5, 8, 13, 21, 34, …) relate to Echinacea flowerheads. The number of ray florets (aka “petals”) on ab Echinacea head are often Finbonacci numbers, like 13 & 21, but they are often not those numbers. This Wikipedia page describes the relationship between Fibonacci series and florets on flowerheads.

Here are some images of Echinacea heads from the summer (top views). Do you see any interesting patterns?

Top view of head of Echinacea angustifolia. How may ray florets? Click image to enlarge to see pattern of disk florets.
Head of Echinacea angustifolia with two bees
Head of Echinacea angustifolia with two bees
Two heads of Echinacea pallida
Two heads of Echinacea pallida. This species is not native to Minnesota, but it was planted by accident in a prairie restoration in our study area
beetle on head of Echinacea angustifolia
beetle on head of Echinacea angustifolia

Is Minnesota getting shorter?

as asserted in Munroe (2023)?

This is going to be the main agenda item for team Echinacea meeting until the snow melts.

  • Is Minnesota getting
    • thinner?
    • narrower?
    • skinnier?
    • shorter?
  • Will we need to gps every single Echinacea plant again?
    • do we need to do demo too?
    • Maybe instead of annually, we can re-map each plant once per decade
  • Do Echinacea plants feel the squeeze?
    • Does the squishiness make Echinacea happy?
  • Are ground-nesting bee nests getting deeper?
  • Why don’t we have any snow?

carbon in the prairie

There are many reasons we don’t want to lose prairie remnants to woody encroachment or conversion to agriculture. One of them is because we don’t want the Carbon in the soil to go to the atmosphere. Here’s a nice visual derived from IPCC data, 2022.

Compare temperate grasslands to temperate forests and croplands. How does a buckthorn thicket compare to any of these?

pollen and nectar = food for thought

Many plants, including Echinacea angustifolia, flower vigorously during the summer after a prescribed burn. We’ve demonstrated that the benefits of fire for seed production, in many circumstances, are bigger than just the increase in flowering. The additional boost to seed production results from better pollination after fires compared to other times. Now we are trying to figure out what’s going on with pollination–why is it better after a fire? It might be related to pollen or nectar, which are foods for the bees that pollinate Echinacea. Here are two possibilities: 1) after a fire, plants produce more or better pollen or nectar which draws in bees from farther away, so the plants get more visits and better pollination, presumably the bees are happier with abundant & healthy food. 2) after a fire, plants produce less or lower quality pollen or nectar which means bees need to fly to more plants to get a decent meal, so the plants get more visits, and the bees are probably frustrated with skimpier meals and bad food. The third possibility is that plants produce the same quality and quantity of pollen & nectar regardless of fires.

Over the summer we systematically collected pollen and nectar from many Echinacea plants in many populations (19) over many days. Our goal is to evaluate how fires affects the quality and quantity of pollen & nectar produced by Echinacea plants. We are getting close to wrapping up data-entry for our field collection of pollen and nectar from Echinacea angustifolia. Here’s a summary of data-entry progress so far…

[1] "11 sites of data entered twice & verified"

[1] "138 pages of data entered twice & verified"

     site tagCt pageCt 
1      aa     6     11 
2  cg-p01     5     14 
3    eelr     5     13 
4   hulze     6     17 
5   hulzw     5     13 
6  hutche     5     13 
7  hutchw     5      9 
8      kj     6     11 
9   koons     5      9 
10    p02     5     13 
11 p08-tp     5     15 

Each “tagCt” is the number of Echinacea plants we sampled at each site. We will keep you posted!

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

Habitat fragmentation decouples fire-stimulated flowering from plant reproductive fitness

This page has information about the Echinacea Project paper that was published in PNAS on 18 Sept 2023.

Updated 2 October 2023.

A flowering head of the narrow-leaved purple coneflower (Echinacea angustifolia). Credit: Jared Beck
A prescribed burn of a prairie restoration. Credit: Stuart Wagenius.

Weather for burning

Reliable forecasts and accurate assessments of current conditions are critical for conducting prescribed burns. We are fortunate to have many weather resources. Here are the sources I use for planning and conducting prescribed burns.

2021 Update: Cirsium hillii fire & fitness

We are still monitoring the fate of the lone patch of Hill’s thistle at Hegg Lake WMA. It is the only patch in our study area, as far as we know. On 8 September 2021, Jared & Stuart used a stake file to find corners of the plot that was shot in 2014. We flagged the corners and did not see any flowering rosettes within. We shot coordinates for five basal rosettes. Two rosettes were outside of the plot near the SW corner. We scanned nearby and saw no more rosettes outside the plot. One Asclepias viridiflora plant was flagged within the plot. I regret I took no photos.

  • Start year: 2014
  • Location: Hegg Lake WMA
  • Data collected:
    • GPS coordinates ~Dropbox\geospatialDataBackup2021\convertedTXT2021\CIRSIUM_20210908_DARW.txt
    • notes. see file 2021-09-08notesCirsiumHillii.pdf
  • Samples or specimens collected: none
  • Products: none

You can find more information about our experiment on how fire affects the fitness of Cirsium hillii on previous flog posts regarding this experiment and on the background page for this experiment.