Good news! We managed to get through randomizing the first batch! Now we are working our way through the second batch, and so far, things have been going pretty well in terms of pace and efficiency for both cleaning and randomization. Overall, we have seen a considerably wide range of head counts in the Liatris plants, but predation rates have been relatively low compared to what was observed in 2021’s data. Who knows what we will find in the next several batches, but I am pretty excited about the progress made so far and the results we may see. Hopefully, we will complete the next batch within the next few weeks, if not sooner.
So far, things are going well in the randomization step, but there is still quite a ways to go to complete the first batch of Liatris plants. However, we have counted a considerable number of achenes that have been eaten, and we are starting to get a rough estimate of the predation rate per Liatris plant. We are finding that there are, on average, 1 to 3 achenes eaten per plant out of a total of at least 30 randomly selected achenes. This equals approximately a 3 to 10 percent range for what has been found, but we have also found a few that have had either none or many achenes eaten. In light of these findings, I think we are heading in the right direction with the project, but hopefully, we will need to get much more work done to get through all five batches. Hopefully, we will have all the plants cleaned and randomized before the burning season (which starts in April), but it will take a lot to get to that goal within a little over a month’s worth of time. However, the good news is whether or not we meet our goal, there will be more than enough data to work with, and ultimately we can come to conclusions at the end.
In lab today, I started the process of randomization. This step in the project does take some time and patience, but all of it is worthwhile toward reducing bias and collecting achenes that can be x-rayed or identified as eaten. Similar to the randomization of achenes from Echinacea plants, sheets of randomization and counting grids are used. In addition, we also use plastic bags, white envelopes, stickers, tweezers, and a magnifying glass for this procedure. The first step involves pouring the achenes evenly across the randomization grid and ensuring all the achenes are placed in a specific square on the grid without being on the lines. Then using a randomized list of grid coordinates, we go down the list until we hit a coordinate (an example would be “B2”) with achenes present. We then examined each achene in the selected coordinate to see if there was any predation. If less than 30 achenes were counted in the coordinate, we randomly selected another one going down the randomization list. Once we categorized 30 achenes as either eaten or eligible for x-ray, we took our white envelope and plastic bag and put stickers on them. The envelope will store the eaten achenes while the plastic bag will contain the achenes ready to be x-rayed. On the envelope, we write the date, initials, and the quantities of achenes eaten, not eaten, and uninformative. After putting the achenes in their respective containers, we put them in a pile marked “randomized,” and we move on to the next one. As of today, we managed to get through a little over one third of our first batch, so we still have much work to do before proceeding onward.
After cleaning Liatris plants for a week, I am happy to say that the first of five batches are now finished. Now that the first batch is completed, the project’s next step is ready to begin. The process of randomization will be the next step in the project. This step will involve the random selection of achenes from each plant to avoid bias and separation of achenes that are either qualified for being x-rayed or not. Luckily, both groupings will have a role in the project’s studies. X-rayed achenes will inform us about pollination and reproductive outcomes for each head of a Liatris plant. On the other hand, non-x-rayed achenes can be assessed for why they cannot be x-rayed, including what types of damage the achenes have and if any predation occurred toward those achenes. My research question will focus specifically on seed predation, so using the non-x-rayed achenes will be essential. I am still working on a finalized research question relating to seed predation, but seeing the progress made so far has me excited about what will come next in the project and toward finalizing my research question.
I am happy to say that the Liatris Project is off to a good start. After taking inventory of all the Liatris plants this past week, I got to start the cleaning process. A total of 293 Liatris plants have been counted in the inventory, and all have been sorted randomly into 5 different batches. Today, I got to start cleaning the ones in the 1st batch, and while cleaning, I noticed several similarities and differences compared to cleaning Echinacea plants. Overall, I found that Liatris achenes were much easier to extract from the plant than Echinacea achenes, but counting them proved much more challenging. To make things easier, random selection sheets of different numerical ranges were arranged that listed random numbers from left to right down the sheets. Using these sheets, I could randomly pick out a flower head and count the number of achenes associated with that head. I also had to observe if any achenes were missing from each head on a Liatris plant. I recorded the total number of heads per plant and the number of heads with no achenes, some achenes, or all achenes missing. After taking these recordings, I removed all the other achenes present on the Liatris plants and sorted them into an envelope. Any chaff leftover got put into a separate envelope labeled as “chaff.” So far, a handful of plants have been cleaned, but there is still a long way to go.
Today will mark the beginning of a new project that I will conduct analyzing Liatris aspera (Rough Blazing Star). Like with the Echinacea Project, this project will look at reproductive quantities of Liatris and the potential factors for influencing plant reproduction. At the moment, a specific research question is still in the works and the actual project requires some introductory steps that need to be completed. In the lab, I conducted inventory checks for the Liatris plants that have been harvested and made sure their were not any errors in what was taken into inventory. While doing the checking, I had Leah help me make sure everything was accounted for. Trying to do this alone would have been frustrating so I send my absolute thanks for helping me out with this part. As for the next steps in the project, I hope to begin cleaning the Liatris plants next week and start to come up with a potential research question in the near future. Very exciting things to come!
Beginning in summer 2021, we have been studying fire effects on Liatris aspera across patches of remnant prairie in Solem Township, MN. Six of these remnants burned in spring of 2021, and five remnants burned in spring 2022. During 2022, we expanded our efforts and collected data at five additional (smaller sites). The (absurdly) high density of flowering Liatris during summer 2022 led us to establish 1 meter wide, randomly placed transects in many sites. Despite our efforts and stated goal of not mapping as many Liatris as we did in summer 2021 (when we mapped 2400+ flowering plants across 23 remnant patches), we managed to overshoot our 2021 counts by at least 33%. Yes, we mapped well over 3200 flowering Liatris during summer 2022 with but a single functioning GPS… We harvested seed from 291 randomly selected Liatris.
Start year: 2021
Location: 28 patches of remnant prairie in and around Solem Township, MN
Overlaps with: Foolishness and shenanigans
Data collected: Demographic and spatial data housed in the remla Bitbucket repo
Samples or specimens collected: Harvested seed heads have been dried and are located in Jared’s office. These need to be inventoried, cleaned, randomized, scored for seed predation, X-rayed, and classified.
Products: Stay tuned!
You can read more about the Liatris fire and flowering project, as well as links to prior flog entries about this experiment, on the background page for this experiment.
Good news on the Liatris front: all hands-on work, from harvesting to x-raying, is complete! The process began in the summer of 2021 and involved lots of help from the field crew, wise, long-term Team Echinacea members, eager and efficient short-term members, and everyone in between.
Mia V and I were also able to complete data entry and data cleaning today, paving the road forward for analysis.
Now that we’re moving on to computer work, we came up with some primary questions to pursue (and some hypotheses):
Is there a significant difference in seed predation rates between burned and unburned and unburned remnants?
We suspect that predation will be higher in burned remnants because density of plants will be higher
Is there a correlation between seed predation rates and plant density?
We hypothesize that higher density will be correlated with higher rates of predation
We will use nearest neighbor as our measure of density
Is there a correlation between individual plant size and predation rates?
We hypothesize that larger plants will receive higher rates of predation
We will use number of flowering heads as our measure of plant size.
I’m now in the process of making plots to help us visualize the data we’ve collected, and soon we can begin to seek answers for our questions.
Because none of our questions at the moment directly relate to pollination, we don’t need to quantify seed set, which is the “classify” step. Using the x-rays to count how many achenes contain seeds is our method of determining pollination rates (seed = pollinated, no seed = not pollinated). This step will likely stay low priority for awhile, so don’t fret about the empty bar. All part of the plan.
Liatrisaspera 2021 progress in the lab is steadily marching on. Thanks to the work of the Carleton externs last winter, we began Northwestern’s spring quarter essentially halfway done (only needing to do some brief back-peddling due to a change in protocol).
With the help of work study Mia V., cleaning, the process of removing the achenes from the flowering heads and gather data on achene-per-head count, is completely finished. Mia has also made excellent progress on randomizing, the step where we select a random sample of achenes to be x-rayed as well as quantify seed predation. We’re on track to finish randomizing later this week or next. Following that, we can x-ray the final batch of 56 liatris, allowing us to quantify seed set, and all the hands-on work for our 234 liatris from 2021 will be complete!
Mia and Wyatt cleaning Liatris aspera in the lab
Priorities going forward:
Finish randomizing and x-raying for batch D
Complete randomization data entry and verification
Develop methods of data analysis to compare
Burned vs. unburned predation rates
In regards to density
In regards to number of heads per plant
Develop methods of classifying seed set from x-rays (low priority)
As a part of our research looking into the role fire plays on plant reproduction and population dynamics, we collected geospatial and flowering data on Liatris aspera at 22 prairie remnants in and near Solem Township, MN. Six of these remnants burned in spring of 2021. During the growing season, we collected data on the position, inflorescence count, and number of flowering heads for over 2400 individuals (exact number is unknown still because some individuals were shot twice with the GPS due to calibration errors).
We also randomly selected 234 Liatris as focal plants, which we harvested once they had gone to seed and brought back to the lab for cleaning. We hope to be able to use the inflorescences we collected to quantify seed set and compare density effects between burned and unburned remnants.
Over the summer, Team Echinacea spent 5955 minutes (99 person-hours) shooting Liatris GPS points and 2235 minutes (37 person-hours) harvesting the focal Liatris plants.
Collecting data on a small Liatris
Start year: 2021
Location: 22 prairie remnant sites in and around Solem Township, MN
It's great to see another dissertation chapter published by @lealiatris! This paper uses aster models to disentangle resource- and pollen-limitation of reproductive fitness. https://t.co/RPm7E84quQ
We have a full house in the @chicagobotanic lab today. One side of the table is cleaning Liatris heads, and the other side is cleaning and counting Echinacea. It's been a very productive morning! #communitysciencehttps://t.co/wWREBDQeo2
