2020 Update: ExPt 10 and Gene Flow in the Remnants

During the summer of 2019, Team Echinacea planted over 1400 E. angustifolia seedlings into 12 plots in a prairie restoration at West Central Area High School in Barrett, MN. We planted seedlings from three sources: (1) offspring from exPt1, (2) plants from my gene flow experiment, and (3) offspring from the Big Event. To test how different fire regimes affect fitness in Echinacea, folks from West Central Area plan to apply regular fall burn treatments to four plots, regular spring burn treatments to four other plots, and the remaining four plots will not be burned. I’m not sure if they were able to perform these burns as planned in Fall 2020 given COVID restrictions this spring and fall, but John Van Kempen would be the man to ask about that. I believe they were able to do the burns in the spring.

This summer, the team measured the 1-year old seedlings from my gene flow study in exPt10, as well as a few seedlings from the other plantings within the plot. The seedlings from my gene flow experiment are the offspring of open-pollinated Echinacea in 9 populations in the study area. I am assessing the paternity of these seedlings to understand contemporary pollen movement patterns within and among the remnants. In summer 2018, I mapped and collected leaf tissue from all Echinacea individuals within 800m of the study areas and harvested seedheads from a sample of these individuals (see Reproductive Fitness in Remnants). In spring 2019, I germinated and grew up a sample of the seeds that I harvested to obtain leaf tissue for genotyping.

Then, with the team’s help, I planted these seedlings in exPt10 in June 2019. I also collected seeds and leaf tissue in summer 2019 to repeat this process, but I did not germinate the achenes in the following spring because I was not able to assess seed set due to the broken x-ray machine at the CBG and then COVID-related restrictions. I hope to germinate those this spring and plant in summer 2021. I am working on extracting the DNA from the leaf tissue samples I have, which I will use to match up the genotypes of the offspring (i.e., the seeds) with their most likely father (i.e., the pollen source).

Here are some fun facts about the seedlings we found in exPt 10:

The longest leaf we saw was 19 cm! Most were much smaller (see below).

A histogram of seedling leaf lengths, ranging from 1 to 19 cm

The leafiest plant we saw had 4 leaves (though one had been munched)

A histogram of leaf counts per plant, which ranged from 1 to 4

Overall we found 424 seedlings alive of the 598 that we searched for, or 71%. The ones we didn’t find are probably dead, but we’ll look for them again next year to make sure we didn’t just miss them.

I’m looking forward to seeing these friends again next year.